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br-parser-tools
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1 Commits
master ... tokens

Author SHA1 Message Date
Matthew Butterick 2d5d7ecaaf make it possible to use "start" and "atok" as literal tokens 6 years ago
61 changed files with 5061 additions and 4550 deletions
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45
.github/workflows/ci.yml vendored
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name: CI
on: [push, pull_request]
jobs:
run:
name: "Build using Racket '${{ matrix.racket-version }}' (${{ matrix.racket-variant }})"
runs-on: ubuntu-latest
strategy:
fail-fast: false
matrix:
racket-version: ["6.6", "6.7", "6.8", "6.9", "6.10.1", "6.11", "6.12", "7.0", "7.1", "7.2", "7.3", "7.4", "7.5", "7.6", "7.7", "7.8", "7.9", "current"]
racket-variant: ["BC", "CS"]
# CS builds are only provided for versions 7.4 and up so avoid
# running the job for prior versions.
exclude:
- {racket-version: "6.6", racket-variant: "CS"}
- {racket-version: "6.7", racket-variant: "CS"}
- {racket-version: "6.8", racket-variant: "CS"}
- {racket-version: "6.9", racket-variant: "CS"}
- {racket-version: "6.10.1", racket-variant: "CS"}
- {racket-version: "6.11", racket-variant: "CS"}
- {racket-version: "6.12", racket-variant: "CS"}
- {racket-version: "7.0", racket-variant: "CS"}
- {racket-version: "7.1", racket-variant: "CS"}
- {racket-version: "7.2", racket-variant: "CS"}
- {racket-version: "7.3", racket-variant: "CS"}
steps:
- name: Checkout
uses: actions/checkout@master
- uses: Bogdanp/setup-racket@v0.11
with:
distribution: 'full'
version: ${{ matrix.racket-version }}
variant: ${{ matrix.racket-variant }}
- name: Install BR parser tools
run: raco pkg install --deps search-auto https://github.com/mbutterick/br-parser-tools.git?path=br-parser-tools-lib
- name: Run the br-parser-tools tests
run: xvfb-run raco test -p br-parser-tools-lib

10
README.md
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## br-parser-tools ![Build Status](https://github.com/mbutterick/br-parser-tools/workflows/CI/badge.svg)
## Docs
https://docs.racket-lang.org/br-parser-tools/
## Project status
Complete. This project exists only to support the [`brag`](https://git.matthewbutterick.com/mbutterick/brag) library. Probably a lot of the improvements I made could be merged into the main [`parser-tools`](https://github.com/racket/parser-tools) library, but it is old and delicate. Still, if you want to build a dependency into your project, I suggest you use `parser-tools` (because it’s maintained by the Racket team), not this one.

3
br-parser-tools-doc/br-parser-tools/info.rkt
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#lang info
(define scribblings '(("br-parser-tools.scrbl" (multi-page) (parsing-library))))

240
br-parser-tools-lib/br-parser-tools/examples/read.rkt
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#lang racket/base
;; This implements the equivalent of racket's read-syntax for R5RS scheme.
;; It has not been thoroughly tested. Also it will read an entire file into a
;; list of syntax objects, instead of returning one syntax object at a time
(require (for-syntax racket/base)
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre)
br-parser-tools/yacc
syntax/readerr)
(define-tokens data (DATUM))
(define-empty-tokens delim (OP CP HASHOP QUOTE QUASIQUOTE UNQUOTE UNQUOTE-SPLICING DOT EOF))
(define scheme-lexer
(lexer-src-pos
;; Skip comments, without accumulating extra position information
[(:or scheme-whitespace comment) (return-without-pos (scheme-lexer input-port))]
["#t" (token-DATUM #t)]
["#f" (token-DATUM #f)]
[(:: "#\\" any-char) (token-DATUM (caddr (string->list lexeme)))]
["#\\space" (token-DATUM #\space)]
["#\\newline" (token-DATUM #\newline)]
[(:or (:: initial (:* subsequent)) "+" "-" "...") (token-DATUM (string->symbol lexeme))]
[#\" (token-DATUM (list->string (get-string-token input-port)))]
[#\( 'OP]
[#\) 'CP]
[#\[ 'OP]
[#\] 'CP]
["#(" 'HASHOP]
[num2 (token-DATUM (string->number lexeme 2))]
[num8 (token-DATUM (string->number lexeme 8))]
[num10 (token-DATUM (string->number lexeme 10))]
[num16 (token-DATUM (string->number lexeme 16))]
["'" 'QUOTE]
["`" 'QUASIQUOTE]
["," 'UNQUOTE]
[",@" 'UNQUOTE-SPLICING]
["." 'DOT]
[(eof) 'EOF]))
(define get-string-token
(lexer
[(:~ #\" #\\) (cons (car (string->list lexeme))
(get-string-token input-port))]
[(:: #\\ #\\) (cons #\\ (get-string-token input-port))]
[(:: #\\ #\") (cons #\" (get-string-token input-port))]
[#\" null]))
(define-lex-abbrevs
[letter (:or (:/ "a" "z") (:/ #\A #\Z))]
[digit (:/ #\0 #\9)]
[scheme-whitespace (:or #\newline #\return #\tab #\space #\vtab)]
[initial (:or letter (char-set "!$%&*/:<=>?^_~@"))]
[subsequent (:or initial digit (char-set "+-.@"))]
[comment (:: #\; (:* (:~ #\newline)) #\newline)]
;; See ${PLTHOME}/collects/syntax-color/racket-lexer.rkt for an example of
;; using regexp macros to avoid the cut and paste.
; [numR (:: prefixR complexR)]
; [complexR (:or realR
; (:: realR "@" realR)
; (:: realR "+" urealR "i")
; (:: realR "-" urealR "i")
; (:: realR "+i")
; (:: realR "-i")
; (:: "+" urealR "i")
; (:: "-" urealR "i")
; (:: "+i")
; (:: "-i"))]
; [realR (:: sign urealR)]
; [urealR (:or uintegerR (:: uintegerR "/" uintegerR) decimalR)]
; [uintegerR (:: (:+ digitR) (:* #\#))]
; [prefixR (:or (:: radixR exactness)
; (:: exactness radixR))]
[num2 (:: prefix2 complex2)]
[complex2 (:or real2
(:: real2 "@" real2)
(:: real2 "+" ureal2 "i")
(:: real2 "-" ureal2 "i")
(:: real2 "+i")
(:: real2 "-i")
(:: "+" ureal2 "i")
(:: "-" ureal2 "i")
(:: "+i")
(:: "-i"))]
[real2 (:: sign ureal2)]
[ureal2 (:or uinteger2 (:: uinteger2 "/" uinteger2))]
[uinteger2 (:: (:+ digit2) (:* #\#))]
[prefix2 (:or (:: radix2 exactness)
(:: exactness radix2))]
[radix2 "#b"]
[digit2 (:or "0" "1")]
[num8 (:: prefix8 complex8)]
[complex8 (:or real8
(:: real8 "@" real8)
(:: real8 "+" ureal8 "i")
(:: real8 "-" ureal8 "i")
(:: real8 "+i")
(:: real8 "-i")
(:: "+" ureal8 "i")
(:: "-" ureal8 "i")
(:: "+i")
(:: "-i"))]
[real8 (:: sign ureal8)]
[ureal8 (:or uinteger8 (:: uinteger8 "/" uinteger8))]
[uinteger8 (:: (:+ digit8) (:* #\#))]
[prefix8 (:or (:: radix8 exactness)
(:: exactness radix8))]
[radix8 "#o"]
[digit8 (:/ "0" "7")]
[num10 (:: prefix10 complex10)]
[complex10 (:or real10
(:: real10 "@" real10)
(:: real10 "+" ureal10 "i")
(:: real10 "-" ureal10 "i")
(:: real10 "+i")
(:: real10 "-i")
(:: "+" ureal10 "i")
(:: "-" ureal10 "i")
(:: "+i")
(:: "-i"))]
[real10 (:: sign ureal10)]
[ureal10 (:or uinteger10 (:: uinteger10 "/" uinteger10) decimal10)]
[uinteger10 (:: (:+ digit10) (:* #\#))]
[prefix10 (:or (:: radix10 exactness)
(:: exactness radix10))]
[radix10 (:? "#d")]
[digit10 digit]
[decimal10 (:or (:: uinteger10 suffix)
(:: #\. (:+ digit10) (:* #\#) suffix)
(:: (:+ digit10) #\. (:* digit10) (:* #\#) suffix)
(:: (:+ digit10) (:+ #\#) #\. (:* #\#) suffix))]
[num16 (:: prefix16 complex16)]
[complex16 (:or real16
(:: real16 "@" real16)
(:: real16 "+" ureal16 "i")
(:: real16 "-" ureal16 "i")
(:: real16 "+i")
(:: real16 "-i")
(:: "+" ureal16 "i")
(:: "-" ureal16 "i")
"+i"
"-i")]
[real16 (:: sign ureal16)]
[ureal16 (:or uinteger16 (:: uinteger16 "/" uinteger16))]
[uinteger16 (:: (:+ digit16) (:* #\#))]
[prefix16 (:or (:: radix16 exactness)
(:: exactness radix16))]
[radix16 "#x"]
[digit16 (:or digit (:/ #\a #\f) (:/ #\A #\F))]
[suffix (:or "" (:: exponent-marker sign (:+ digit10)))]
[exponent-marker (:or "e" "s" "f" "d" "l")]
[sign (:or "" "+" "-")]
[exactness (:or "" "#i" "#e")])
(define stx-for-original-property (read-syntax #f (open-input-string "original")))
;; A macro to build the syntax object
(define-syntax (build-so stx)
(syntax-case stx ()
((_ value start end)
(with-syntax ((start-pos (datum->syntax
#'end
(string->symbol
(format "$~a-start-pos"
(syntax->datum #'start)))))
(end-pos (datum->syntax
#'end
(string->symbol
(format "$~a-end-pos"
(syntax->datum #'end)))))
(source (datum->syntax
#'end
'source-name)))
(syntax
(datum->syntax
#f
value
(list source
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos)
(position-offset start-pos)))
stx-for-original-property))))))
(define (scheme-parser source-name)
(parser
(src-pos)
(start s)
(end EOF)
(error (lambda (a name val start end)
(raise-read-error
"read-error"
source-name
(position-line start)
(position-col start)
(position-offset start)
(- (position-offset end)
(position-offset start)))))
(tokens data delim)
(grammar
(s [(sexp-list) (reverse $1)])
(sexp [(DATUM) (build-so $1 1 1)]
[(OP sexp-list CP) (build-so (reverse $2) 1 3)]
[(HASHOP sexp-list CP) (build-so (list->vector (reverse $2)) 1 3)]
[(QUOTE sexp) (build-so (list 'quote $2) 1 2)]
[(QUASIQUOTE sexp) (build-so (list 'quasiquote $2) 1 2)]
[(UNQUOTE sexp) (build-so (list 'unquote $2) 1 2)]
[(UNQUOTE-SPLICING sexp) (build-so (list 'unquote-splicing $2) 1 2)]
[(OP sexp-list DOT sexp CP) (build-so (append (reverse $2) $4) 1 5)])
(sexp-list [() null]
[(sexp-list sexp) (cons $2 $1)]))))
(define (rs sn ip)
(port-count-lines! ip)
((scheme-parser sn) (lambda () (scheme-lexer ip))))
(define readsyntax
(case-lambda ((sn) (rs sn (current-input-port)))
((sn ip) (rs sn ip))))
(provide (rename-out [readsyntax read-syntax]))

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br-parser-tools-lib/br-parser-tools/lex-plt-v200.rkt
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#lang racket/base
(require (for-syntax racket/base)
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre))
(provide epsilon ~
(rename-out [:* *]
[:+ +]
[:? ?]
[:or :]
[:& &]
[:: @]
[:~ ^]
[:/ -]))
(define-lex-trans (epsilon stx)
(syntax-case stx ()
[(_) #'""]))
(define-lex-trans (~ stx)
(syntax-case stx ()
[(_ RE) #'(complement RE)]))

103
br-parser-tools-lib/br-parser-tools/lex-sre.rkt
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#lang racket/base
(require (for-syntax racket/base)
br-parser-tools/lex)
(provide (rename-out [sre-* *]
[sre-+ +]
[sre-= =]
[sre->= >=]
[sre-or or]
[sre-- -]
[sre-/ /])
? ** : seq & ~ /-only-chars)
(define-lex-trans (sre-* stx)
(syntax-case stx ()
[(_ RE ...)
#'(repetition 0 +inf.0 (union RE ...))]))
(define-lex-trans (sre-+ stx)
(syntax-case stx ()
[(_ RE ...)
#'(repetition 1 +inf.0 (union RE ...))]))
(define-lex-trans (? stx)
(syntax-case stx ()
[(_ RE ...)
#'(repetition 0 1 (union RE ...))]))
(define-lex-trans (sre-= stx)
(syntax-case stx ()
[(_ N RE ...)
#'(repetition N N (union RE ...))]))
(define-lex-trans (sre->= stx)
(syntax-case stx ()
[(_ N RE ...)
#'(repetition N +inf.0 (union RE ...))]))
(define-lex-trans (** stx)
(syntax-case stx ()
[(_ LOW #f RE ...)
#'(** LOW +inf.0 RE ...)]
[(_ LOW HIGH RE ...)
#'(repetition LOW HIGH (union RE ...))]))
(define-lex-trans (sre-or stx)
(syntax-case stx ()
[(_ RE ...)
#'(union RE ...)]))
(define-lex-trans (: stx)
(syntax-case stx ()
[(_ RE ...)
#'(concatenation RE ...)]))
(define-lex-trans (seq stx)
(syntax-case stx ()
[(_ RE ...)
#'(concatenation RE ...)]))
(define-lex-trans (& stx)
(syntax-case stx ()
[(_ RE ...)
#'(intersection RE ...)]))
(define-lex-trans (~ stx)
(syntax-case stx ()
[(_ RE ...)
#'(char-complement (union RE ...))]))
;; set difference
(define-lex-trans (sre-- stx)
(syntax-case stx ()
[(_)
(raise-syntax-error #f
"must have at least one argument"
stx)]
[(_ BIG-RE RE ...)
#'(& BIG-RE (complement (union RE ...)))]))
(define-lex-trans (sre-/ stx)
(syntax-case stx ()
[(_ RANGE ...)
(let ([chars
(apply append (for/list ([r (in-list (syntax->list #'(RANGE ...)))])
(let ([x (syntax-e r)])
(cond
[(char? x) (list x)]
[(string? x) (string->list x)]
[else
(raise-syntax-error #f "not a char or string" stx r)]))))])
(unless (even? (length chars))
(raise-syntax-error #f "not given an even number of characters" stx))
#`(/-only-chars #,@chars))]))
(define-lex-trans (/-only-chars stx)
(syntax-case stx ()
[(_ C1 C2)
#'(char-range C1 C2)]
[(_ C1 C2 C ...)
#'(union (char-range C1 C2) (/-only-chars C ...))]))

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br-parser-tools-lib/br-parser-tools/lex.rkt
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#lang racket/base
;; Provides the syntax used to create lexers and the functions needed to
;; create and use the buffer that the lexer reads from. See docs.
(require (for-syntax racket/list
racket/syntax
syntax/stx
syntax/define
syntax/boundmap
"private-lex/util.rkt"
"private-lex/actions.rkt"
"private-lex/front.rkt"
"private-lex/unicode-chars.rkt"
racket/base
racket/promise))
(require racket/stxparam
syntax/readerr
"private-lex/token.rkt")
(provide lexer lexer-src-pos lexer-srcloc define-lex-abbrev define-lex-abbrevs define-lex-trans
;; Dealing with tokens and related structures
define-tokens define-empty-tokens token-name token-value token?
(struct-out position)
(struct-out position-token)
(struct-out srcloc-token)
;; File path for highlighting errors while lexing
file-path
lexer-file-path ;; alternate name
;; Lex abbrevs for unicode char sets.
any-char any-string nothing alphabetic lower-case upper-case title-case
numeric symbolic punctuation graphic whitespace blank iso-control
;; A regular expression operator
char-set)
;; wrap-action: syntax-object src-pos? -> syntax-object
(define-for-syntax (wrap-action action src-loc-style)
(with-syntax ([action-stx
(cond
[(eq? src-loc-style 'lexer-src-pos)
#`(let/ec ret
(syntax-parameterize
([return-without-pos (make-rename-transformer #'ret)])
(make-position-token #,action start-pos end-pos)))]
[(eq? src-loc-style 'lexer-srcloc)
#`(let/ec ret
(syntax-parameterize
([return-without-srcloc (make-rename-transformer #'ret)])
(make-srcloc-token #,action lexeme-srcloc)))]
[else action])])
(syntax/loc action
(λ (start-pos-p end-pos-p lexeme-p input-port-p)
(define lexeme-srcloc-p (make-srcloc (object-name input-port-p)
(position-line start-pos-p)
(position-col start-pos-p)
(position-offset start-pos-p)
(and (number? (position-offset end-pos-p))
(number? (position-offset start-pos-p))
(- (position-offset end-pos-p)
(position-offset start-pos-p)))))
(syntax-parameterize
([start-pos (make-rename-transformer #'start-pos-p)]
[end-pos (make-rename-transformer #'end-pos-p)]
[lexeme (make-rename-transformer #'lexeme-p)]
[input-port (make-rename-transformer #'input-port-p)]
[lexeme-srcloc (make-rename-transformer #'lexeme-srcloc-p)])
action-stx)))))
(define-for-syntax (make-lexer-macro caller src-loc-style)
(λ (stx)
(syntax-case stx ()
[(_ . RE+ACTS)
(with-disappeared-uses
(let ()
(define spec/re-acts (syntax->list #'RE+ACTS))
(for/and ([x (in-list spec/re-acts)])
(syntax-case x ()
[(RE ACT) #t]
[else (raise-syntax-error caller "not a regular expression / action pair" stx x)]))
(define eof-act (get-special-action spec/re-acts #'eof (case src-loc-style
[(lexer-src-pos) #'(return-without-pos eof)]
[(lexer-srcloc) #'(return-without-srcloc eof)]
[else #'eof])))
(define spec-act (get-special-action spec/re-acts #'special #'(void)))
(define spec-comment-act (get-special-action spec/re-acts #'special-comment #'#f))
(define ids (list #'special #'special-comment #'eof))
(define re-acts (filter (λ (spec/re-act)
(syntax-case spec/re-act ()
[((special) act)
(not (ormap
(λ (x)
(and (identifier? #'special)
(module-or-top-identifier=? #'special x)))
ids))]
[_ #t])) spec/re-acts))
(define names (map (λ (x) (datum->syntax #f (gensym))) re-acts))
(define acts (map (λ (x) (stx-car (stx-cdr x))) re-acts))
(define re-actnames (map (λ (re-act name) (list (stx-car re-act) name)) re-acts names))
(when (null? spec/re-acts)
(raise-syntax-error caller "expected at least one action" stx))
(define-values (trans start action-names no-look) (build-lexer re-actnames))
(when (vector-ref action-names start) ;; Start state is final
(unless (and
;; All the successor states are final
(vector? (vector-ref trans start))
(andmap (λ (x) (vector-ref action-names (vector-ref x 2)))
(vector->list (vector-ref trans start)))
;; Each character has a successor state
(let loop ([check 0]
[nexts (vector->list (vector-ref trans start))])
(cond
[(null? nexts) #f]
[else
(let ([next (car nexts)])
(and (= (vector-ref next 0) check)
(let ([next-check (vector-ref next 1)])
(or (>= next-check max-char-num)
(loop (add1 next-check) (cdr nexts))))))])))
(eprintf "warning: lexer at ~a can accept the empty string\n" stx)))
(with-syntax ([START-STATE-STX start]
[TRANS-TABLE-STX trans]
[NO-LOOKAHEAD-STX no-look]
[(NAME ...) names]
[(ACT ...) (map (λ (a) (wrap-action a src-loc-style)) acts)]
[(ACT-NAME ...) (vector->list action-names)]
[SPEC-ACT-STX (wrap-action spec-act src-loc-style)]
[HAS-COMMENT-ACT?-STX (if (syntax-e spec-comment-act) #t #f)]
[SPEC-COMMENT-ACT-STX (wrap-action spec-comment-act src-loc-style)]
[EOF-ACT-STX (wrap-action eof-act src-loc-style)])
(syntax/loc stx (let ([NAME ACT] ...)
(let ([proc (lexer-body START-STATE-STX
TRANS-TABLE-STX
(vector ACT-NAME ...)
NO-LOOKAHEAD-STX
SPEC-ACT-STX
HAS-COMMENT-ACT?-STX
SPEC-COMMENT-ACT-STX
EOF-ACT-STX)])
;; reverse eta to get named procedures:
(λ (port) (proc port))))))))])))
(define-syntax lexer (make-lexer-macro 'lexer #f))
(define-syntax lexer-src-pos (make-lexer-macro 'lexer-src-pos 'lexer-src-pos))
(define-syntax lexer-srcloc (make-lexer-macro 'lexer-srcloc 'lexer-srcloc))
(define-syntax (define-lex-abbrev stx)
(syntax-case stx ()
[(_ NAME RE) (identifier? #'NAME)
(syntax/loc stx
(define-syntax NAME
(make-lex-abbrev (λ () (quote-syntax RE)))))]
[_ (raise-syntax-error 'define-lex-abbrev "form should be (define-lex-abbrev name re)" stx)]))
(define-syntax (define-lex-abbrevs stx)
(syntax-case stx ()
[(_ . XS)
(with-syntax ([(ABBREV ...) (map
(λ (a)
(syntax-case a ()
[(NAME RE) (identifier? #'NAME)
(syntax/loc a (define-lex-abbrev NAME RE))]
[_ (raise-syntax-error
#f
"form should be (define-lex-abbrevs (name re) ...)"
stx
a)]))
(syntax->list #'XS))])
(syntax/loc stx (begin ABBREV ...)))]
[_ (raise-syntax-error #f "form should be (define-lex-abbrevs (name re) ...)" stx)]))
(define-syntax (define-lex-trans stx)
(syntax-case stx ()
[(_ name-form body-form)
(let-values (((name body)
(normalize-definition #'(define-syntax name-form body-form) #'λ)))
#`(define-syntax #,name
(let ((func #,body))
(unless (procedure? func)
(raise-syntax-error 'define-lex-trans "expected a procedure as the transformer, got ~e" func))
(unless (procedure-arity-includes? func 1)
(raise-syntax-error 'define-lex-trans "expected a procedure that accepts 1 argument as the transformer, got ~e" func))
(make-lex-trans func))))]
[_
(raise-syntax-error
#f
"form should be (define-lex-trans name transformer)"
stx)]))
(define (get-next-state-helper char min max table)
(cond
[(>= min max) #f]
[else
(define try (quotient (+ min max) 2))
(define el (vector-ref table try))
(define r1 (vector-ref el 0))
(define r2 (vector-ref el 1))
(cond
[(and (>= char r1) (<= char r2)) (vector-ref el 2)]
[(< char r1) (get-next-state-helper char min try table)]
[else (get-next-state-helper char (add1 try) max table)])]))
(define (get-next-state char table)
(and table (get-next-state-helper char 0 (vector-length table) table)))
(define ((lexer-body start-state trans-table actions no-lookahead special-action
has-special-comment-action? special-comment-action eof-action) ip)
(define (lexer ip)
(define first-pos (get-position ip))
(define first-char (peek-char-or-special ip 0))
;(printf "(peek-char-or-special port 0) = ~e\n" first-char)
(cond
[(eof-object? first-char)
(do-match ip first-pos eof-action (read-char-or-special ip))]
[(special-comment? first-char)
(read-char-or-special ip)
(cond
(has-special-comment-action?
(do-match ip first-pos special-comment-action #f))
(else (lexer ip)))]
[(not (char? first-char))
(do-match ip first-pos special-action (read-char-or-special ip))]
[else
(let lexer-loop (
;; current-state
[state start-state]
;; the character to transition on
[char first-char]
;; action for the longest match seen thus far
;; including a match at the current state
[longest-match-action
(vector-ref actions start-state)]
;; how many bytes precede char
[length-bytes 0]
;; how many characters have been read
;; including the one just read
[length-chars 1]
;; how many characters are in the longest match
[longest-match-length 0])
(define next-state
(cond
[(not (char? char)) #f]
[else (get-next-state (char->integer char)
(vector-ref trans-table state))]))
(cond
[(not next-state)
(check-match ip first-pos longest-match-length
length-chars longest-match-action)]
[(vector-ref no-lookahead next-state)
(define act (vector-ref actions next-state))
(check-match ip
first-pos
(if act length-chars longest-match-length)
length-chars
(if act act longest-match-action))]
[else
(define act (vector-ref actions next-state))
(define next-length-bytes (+ (char-utf-8-length char) length-bytes))
(define next-char (peek-char-or-special ip next-length-bytes))
#;(printf "(peek-char-or-special port ~e) = ~e\n"
next-length-bytes next-char)
(lexer-loop next-state
next-char
(if act
act
longest-match-action)
next-length-bytes
(add1 length-chars)
(if act
length-chars
longest-match-length))]))]))
(unless (input-port? ip)
(raise-argument-error 'lexer "input-port?" 0 ip))
(lexer ip))
(define (check-match lb first-pos longest-match-length length longest-match-action)
(unless longest-match-action
(define match (read-string length lb))
(define end-pos (get-position lb))
(raise-read-error
(format "lexer: No match found in input starting with: ~v" match)
(file-path)
(position-line first-pos)
(position-col first-pos)
(position-offset first-pos)
(- (position-offset end-pos) (position-offset first-pos))))
(define match (read-string longest-match-length lb))
;(printf "(read-string ~e port) = ~e\n" longest-match-length match)
(do-match lb first-pos longest-match-action match))
(define file-path (make-parameter #f))
(define lexer-file-path file-path)
(define (do-match ip first-pos action value)
#;(printf "(action ~a ~a ~a ~a)\n"
(position-offset first-pos) (position-offset (get-position ip)) value ip)
(action first-pos (get-position ip) value ip))
(define (get-position ip)
(define-values (line col off) (port-next-location ip))
(make-position off line col))
(define-syntax (create-unicode-abbrevs stx)
(syntax-case stx ()
[(_ CTXT)
(with-syntax ([(RANGES ...) (for/list ([range (in-list (list (force alphabetic-ranges)
(force lower-case-ranges)
(force upper-case-ranges)
(force title-case-ranges)
(force numeric-ranges)
(force symbolic-ranges)
(force punctuation-ranges)
(force graphic-ranges)
(force whitespace-ranges)
(force blank-ranges)
(force iso-control-ranges)))])
`(union ,@(map (λ (x)
`(char-range ,(integer->char (car x))
,(integer->char (cdr x))))
range)))]
[(NAMES ...) (for/list ([sym (in-list '(alphabetic
lower-case
upper-case
title-case
numeric
symbolic
punctuation
graphic
whitespace
blank
iso-control))])
(datum->syntax #'CTXT sym #f))])
#'(define-lex-abbrevs (NAMES RANGES) ...))]))
(define-lex-abbrev any-char (char-complement (union)))
(define-lex-abbrev any-string (intersection))
(define-lex-abbrev nothing (union))
(create-unicode-abbrevs #'here)
(define-lex-trans (char-set stx)
(syntax-case stx ()
[(_ STR)
(string? (syntax-e #'STR))
(with-syntax ([(CHAR ...) (string->list (syntax-e #'STR))])
#'(union CHAR ...))]))
(define-syntax provide-lex-keyword
(syntax-rules ()
[(_ ID ...)
(begin
(define-syntax-parameter ID
(make-set!-transformer
(λ (stx)
(raise-syntax-error
'provide-lex-keyword
(format "use of a lexer keyword (~a) is not in an appropriate lexer action" 'ID)
stx))))
...
(provide ID ...))]))
(provide-lex-keyword start-pos end-pos lexeme lexeme-srcloc input-port return-without-pos return-without-srcloc)

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br-parser-tools-lib/br-parser-tools/private-lex/deriv.rkt
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#lang racket/base
(require racket/list
(prefix-in is: data/integer-set)
"re.rkt"
"util.rkt")
(provide build-dfa print-dfa (struct-out dfa))
(define e (build-epsilon))
(define z (build-zero))
;; Don't do anything with this one but extract the chars
(define all-chars (->re `(char-complement (union)) (make-cache)))
;; get-char-groups : re bool -> (list-of char-setR?)
;; Collects the char-setRs in r that could be used in
;; taking the derivative of r.
(define (get-char-groups r found-negation)
(cond
[(or (eq? r e) (eq? r z)) null]
[(char-setR? r) (list r)]
[(concatR? r)
(if (re-nullable? (concatR-re1 r))
(append (get-char-groups (concatR-re1 r) found-negation)
(get-char-groups (concatR-re2 r) found-negation))
(get-char-groups (concatR-re1 r) found-negation))]
[(repeatR? r)
(get-char-groups (repeatR-re r) found-negation)]
[(orR? r)
(apply append (map (λ (x) (get-char-groups x found-negation)) (orR-res r)))]
[(andR? r)
(apply append (map (λ (x) (get-char-groups x found-negation)) (andR-res r)))]
[(negR? r)
(if found-negation
(get-char-groups (negR-re r) #t)
(cons all-chars (get-char-groups (negR-re r) #t)))]))
(test-block ((c (make-cache))
(r1 (->re #\1 c))
(r2 (->re #\2 c)))
((get-char-groups e #f) null)
((get-char-groups z #f) null)
((get-char-groups r1 #f) (list r1))
((get-char-groups (->re `(concatenation ,r1 ,r2) c) #f)
(list r1))
((get-char-groups (->re `(concatenation ,e ,r2) c) #f)
(list r2))
((get-char-groups (->re `(concatenation (repetition 0 +inf.0 ,r1) ,r2) c) #f)
(list r1 r2))
((get-char-groups (->re `(repetition 0 +inf.0 ,r1) c) #f)
(list r1))
((get-char-groups
(->re `(union (repetition 0 +inf.0 ,r1)
(concatenation (repetition 0 +inf.0 ,r2) "3") "4") c) #f)
(list r1 r2 (->re "3" c) (->re "4" c)))
((get-char-groups (->re `(complement ,r1) c) #f)
(list all-chars r1))
((get-char-groups
(->re `(intersection (repetition 0 +inf.0 ,r1)
(concatenation (repetition 0 +inf.0 ,r2) "3") "4") c) #f)
(list r1 r2 (->re "3" c) (->re "4" c)))
)
(define loc:member? is:member?)
;; deriveR : re char cache -> re
(define (deriveR r c cache)
(cond
[(or (eq? r e) (eq? r z)) z]
[(char-setR? r)
(if (loc:member? c (char-setR-chars r)) e z)]
[(concatR? r)
(define r1 (concatR-re1 r))
(define r2 (concatR-re2 r))
(define d (build-concat (deriveR r1 c cache) r2 cache))
(if (re-nullable? r1)
(build-or (list d (deriveR r2 c cache)) cache)
d)]
[(repeatR? r)
(build-concat (deriveR (repeatR-re r) c cache)
(build-repeat (sub1 (repeatR-low r))
(sub1 (repeatR-high r))
(repeatR-re r) cache)
cache)]
[(orR? r)
(build-or (map (λ (x) (deriveR x c cache))
(orR-res r))
cache)]
[(andR? r)
(build-and (map (λ (x) (deriveR x c cache))
(andR-res r))
cache)]
[(negR? r)
(build-neg (deriveR (negR-re r) c cache) cache)]))
(test-block ((c (make-cache))
(a (char->integer #\a))
(b (char->integer #\b))
(r1 (->re #\a c))
(r2 (->re `(repetition 0 +inf.0 #\a) c))
(r3 (->re `(repetition 0 +inf.0 ,r2) c))
(r4 (->re `(concatenation #\a ,r2) c))
(r5 (->re `(repetition 0 +inf.0 ,r4) c))
(r6 (->re `(union ,r5 #\a) c))
(r7 (->re `(concatenation ,r2 ,r2) c))
(r8 (->re `(complement ,r4) c))
(r9 (->re `(intersection ,r2 ,r4) c)))
((deriveR e a c) z)
((deriveR z a c) z)
((deriveR r1 b c) z)
((deriveR r1 a c) e)
((deriveR r2 a c) r2)
((deriveR r2 b c) z)
((deriveR r3 a c) r2)
((deriveR r3 b c) z)
((deriveR r4 a c) r2)
((deriveR r4 b c) z)
((deriveR r5 a c) (->re `(concatenation ,r2 ,r5) c))
((deriveR r5 b c) z)
((deriveR r6 a c) (->re `(union (concatenation ,r2 ,r5) "") c))
((deriveR r6 b c) z)
((deriveR r7 a c) (->re `(union (concatenation ,r2 ,r2) ,r2) c))
((deriveR r7 b c) z)
((deriveR r8 a c) (->re `(complement, r2) c))
((deriveR r8 b c) (->re `(complement ,z) c))
((deriveR r9 a c) r2)
((deriveR r9 b c) z)
((deriveR (->re `(repetition 1 2 "ab") c) a c)
(->re `(concatenation "b" (repetition 0 1 "ab")) c)))
;; An re-action is (cons re action)
;; derive : (list-of re-action) char cache -> (union (list-of re-action) #f)
;; applies deriveR to all the re-actions's re parts.
;; Returns #f if the derived state is equivalent to z.
(define (derive r c cache)
(define new-r (for/list ([ra (in-list r)])
(cons (deriveR (car ra) c cache) (cdr ra))))
(if (andmap (λ (x) (eq? z (car x))) new-r)
#f
new-r))
(test-block ((c (make-cache))
(r1 (->re #\1 c))
(r2 (->re #\2 c)))
((derive null (char->integer #\1) c) #f)
((derive (list (cons r1 1) (cons r2 2)) (char->integer #\1) c)
(list (cons e 1) (cons z 2)))
((derive (list (cons r1 1) (cons r2 2)) (char->integer #\3) c) #f))
;; get-final : (list-of re-action) -> (union #f syntax-object)
;; An re that accepts e represents a final state. Return the
;; action from the first final state or #f if there is none.
(define (get-final res)
(cond
[(null? res) #f]
[(re-nullable? (caar res)) (cdar res)]
[else (get-final (cdr res))]))
(test-block ((c->i char->integer)
(c (make-cache))
(r1 (->re #\a c))
(r2 (->re #\b c))
(b (list (cons z 1) (cons z 2) (cons z 3) (cons e 4) (cons z 5)))
(a (list (cons r1 1) (cons r2 2))))
((derive null (c->i #\a) c) #f)
((derive a (c->i #\a) c) (list (cons e 1) (cons z 2)))
((derive a (c->i #\b) c) (list (cons z 1) (cons e 2)))
((derive a (c->i #\c) c) #f)
((derive (list (cons (->re `(union " " "\n" ",") c) 1)
(cons (->re `(concatenation (repetition 0 1 "-")
(repetition 1 +inf.0 (char-range "0" "9"))) c) 2)
(cons (->re `(concatenation "-" (repetition 1 +inf.0 "-")) c) 3)
(cons (->re "[" c) 4)
(cons (->re "]" c) 5)) (c->i #\[) c)
b)
((get-final a) #f)
((get-final (list (cons e 1) (cons e 2))) 1)
((get-final b) 4))
;; A state is (make-state (list-of re-action) nat)
(define-struct state (spec index))
;; get->key : re-action -> (list-of nat)
;; states are indexed by the list of indexes of their res
(define (get-key s)
(map (λ (x) (re-index (car x))) s))
(define loc:partition is:partition)
;; compute-chars : (list-of state) -> (list-of char-set)
;; Computed the sets of equivalent characters for taking the
;; derivative of the car of st. Only one derivative per set need to be taken.
(define (compute-chars st)
(cond
[(null? st) null]
[else
(loc:partition (map char-setR-chars
(apply append (map (λ (x) (get-char-groups (car x) #f))
(state-spec (car st))))))]))
(test-block ((c (make-cache))
(c->i char->integer)
(r1 (->re `(char-range #\1 #\4) c))
(r2 (->re `(char-range #\2 #\3) c)))
((compute-chars null) null)
((compute-chars (list (make-state null 1))) null)
((map is:integer-set-contents
(compute-chars (list (make-state (list (cons r1 1) (cons r2 2)) 2))))
(list (is:integer-set-contents (is:make-range (c->i #\2) (c->i #\3)))
(is:integer-set-contents (is:union (is:make-range (c->i #\1))
(is:make-range (c->i #\4)))))))
;; A dfa is (make-dfa int int
;; (list-of (cons int syntax-object))
;; (list-of (cons int (list-of (cons char-set int)))))
;; Each transitions is a state and a list of chars with the state to transition to.
;; The finals and transitions are sorted by state number, and duplicate free.
(define-struct dfa (num-states start-state final-states/actions transitions) #:inspector (make-inspector))
(define loc:get-integer is:get-integer)
;; build-dfa : (list-of re-action) cache -> dfa
(define (build-dfa rs cache)
(let* ([transitions (make-hash)]
[get-state-number (make-counter)]
[start (make-state rs (get-state-number))])
(cache (cons 'state (get-key rs)) (λ () start))
(let loop ([old-states (list start)]
[new-states null]
[all-states (list start)]
[cs (compute-chars (list start))])
(cond
[(and (null? old-states) (null? new-states))
(make-dfa (get-state-number) (state-index start)
(sort (for*/list ([state (in-list all-states)]
[val (in-value (cons (state-index state) (get-final (state-spec state))))]
#:when (cdr val))
val)
< #:key car)
(sort (hash-map transitions
(λ (state trans)
(cons (state-index state)
(for/list ([t (in-list trans)])
(cons (car t)
(state-index (cdr t)))))))
< #:key car))]
[(null? old-states)
(loop new-states null all-states (compute-chars new-states))]
[(null? cs)
(loop (cdr old-states) new-states all-states (compute-chars (cdr old-states)))]
[else
(define state (car old-states))
(define c (car cs))
(define new-re (derive (state-spec state) (loc:get-integer c) cache))
(cond
[new-re
(let* ([new-state? #f]
[new-state (cache (cons 'state (get-key new-re))
(λ ()
(set! new-state? #t)
(make-state new-re (get-state-number))))]
[new-all-states (if new-state? (cons new-state all-states) all-states)])
(hash-set! transitions
state
(cons (cons c new-state)
(hash-ref transitions state
(λ () null))))
(cond
[new-state?
(loop old-states (cons new-state new-states) new-all-states (cdr cs))]
[else
(loop old-states new-states new-all-states (cdr cs))]))]
[else (loop old-states new-states all-states (cdr cs))])]))))
(define (print-dfa x)
(printf "number of states: ~a\n" (dfa-num-states x))
(printf "start state: ~a\n" (dfa-start-state x))
(printf "final states: ~a\n" (map car (dfa-final-states/actions x)))
(for-each (λ (trans)
(printf "state: ~a\n" (car trans))
(for-each (λ (rule)
(printf " -~a-> ~a\n"
(is:integer-set-contents (car rule))
(cdr rule)))
(cdr trans)))
(dfa-transitions x)))
(define (build-test-dfa rs)
(define c (make-cache))
(build-dfa (map (λ (x) (cons (->re x c) 'action)) rs) c))
#|
(define t1 (build-test-dfa null))
(define t2 (build-test-dfa `(#\a)))
(define t3 (build-test-dfa `(#\a #\b)))
(define t4 (build-test-dfa `((repetition 0 +inf.0 #\a)
(repetition 0 +inf.0 (concatenation #\a #\b)))))
(define t5 (build-test-dfa `((concatenation (repetition 0 +inf.0 (union #\0 #\1)) #\1))))
(define t6 (build-test-dfa `((repetition 0 +inf.0 (repetition 0 +inf.0 #\a))
(repetition 0 +inf.0 (concatenation #\b (repetition 1 +inf.0 #\b))))))
(define t7 (build-test-dfa `((concatenation (repetition 0 +inf.0 #\a) (repetition 0 +inf.0 #\b)
(repetition 0 +inf.0 #\c) (repetition 0 +inf.0 #\d)
(repetition 0 +inf.0 #\e)))))
(define t8
(build-test-dfa `((concatenation (repetition 0 +inf.0 (union #\a #\b)) #\a (union #\a #\b)
(union #\a #\b) (union #\a #\b) (union #\a #\b)))))
(define t9 (build-test-dfa `((concatenation "/*"
(complement (concatenation (intersection) "*/" (intersection)))
"*/"))))
(define t11 (build-test-dfa `((complement "1"))))
(define t12 (build-test-dfa `((concatenation (intersection (concatenation (repetition 0 +inf.0 "a") "b")
(concatenation "a" (repetition 0 +inf.0 "b")))
"ab"))))
(define x (build-test-dfa `((union " " "\n" ",")
(concatenation (repetition 0 1 "-") (repetition 1 +inf.0 (char-range "0" "9")))
(concatenation "-" (repetition 1 +inf.0 "-"))
"["
"]")))
(define y (build-test-dfa
`((repetition 1 +inf.0
(union (concatenation "|" (repetition 0 +inf.0 (char-complement "|")) "|")
(concatenation "|" (repetition 0 +inf.0 (char-complement "|"))))))))
(define t13 (build-test-dfa `((intersection (concatenation (intersection) "111" (intersection))
(complement (union (concatenation (intersection) "01")
(repetition 1 +inf.0 "1")))))))
(define t14 (build-test-dfa `((complement "1")))))
|#

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br-parser-tools-lib/br-parser-tools/private-lex/front.rkt
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#lang racket/base
(require racket/base
racket/match
(prefix-in is: data/integer-set)
racket/list
syntax/stx
"util.rkt"
"stx.rkt"
"re.rkt"
"deriv.rkt")
(provide build-lexer)
(define-syntax time-label
(syntax-rules ()
((_ l e ...)
(begin
(printf "~a: " l)
(time (begin e ...))))))
;; A table is either
;; - (vector-of (union #f nat))
;; - (vector-of (vector-of (vector nat nat nat)))
(define loc:integer-set-contents is:integer-set-contents)
;; dfa->1d-table : dfa -> (same as build-lexer)
(define (dfa->1d-table dfa)
(define state-table (make-vector (dfa-num-states dfa) #f))
(define transition-cache (make-hasheq))
(for ([trans (in-list (dfa-transitions dfa))])
(match-define (cons from-state all-chars/to) trans)
(define flat-all-chars/to
(sort
(for*/list ([chars/to (in-list all-chars/to)]
[char-ranges (in-value (loc:integer-set-contents (car chars/to)))]
[to (in-value (cdr chars/to))]
[char-range (in-list char-ranges)])
(define entry (vector (car char-range) (cdr char-range) to))
(hash-ref transition-cache entry (λ ()
(hash-set! transition-cache
entry
entry)
entry)))
< #:key (λ (v) (vector-ref v 0))))
(vector-set! state-table from-state (list->vector flat-all-chars/to)))
state-table)
(define loc:foldr is:foldr)
;; dfa->2d-table : dfa -> (same as build-lexer)
(define (dfa->2d-table dfa)
;; char-table : (vector-of (union #f nat))
;; The lexer table, one entry per state per char.
;; Each entry specifies a state to transition to.
;; #f indicates no transition
(define char-table (make-vector (* 256 (dfa-num-states dfa)) #f))
;; Fill the char-table vector
(for* ([trans (in-list (dfa-transitions dfa))]
[chars/to (in-list (cdr trans))])
(define from-state (car trans))
(define to-state (cdr chars/to))
(loc:foldr (λ (char _)
(vector-set! char-table
(bitwise-ior
char
(arithmetic-shift from-state 8))
to-state))
(void)
(car chars/to)))
char-table)
;; dfa->actions : dfa -> (vector-of (union #f syntax-object))
;; The action for each final state, #f if the state isn't final
(define (dfa->actions dfa)
(define actions (make-vector (dfa-num-states dfa) #f))
(for ([state/action (in-list (dfa-final-states/actions dfa))])
(vector-set! actions (car state/action) (cdr state/action)))
actions)
;; dfa->no-look : dfa -> (vector-of bool)
;; For each state whether the lexer can ignore the next input.
;; It can do this only if there are no transitions out of the
;; current state.
(define (dfa->no-look dfa)
(define no-look (make-vector (dfa-num-states dfa) #t))
(for ([trans (in-list (dfa-transitions dfa))])
(vector-set! no-look (car trans) #f))
no-look)
(test-block ((d1 (make-dfa 1 1 (list) (list)))
(d2 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3))))))
(d3 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 100 200) 0)
(cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3)))))))
((dfa->2d-table d1) (make-vector 256 #f))
((dfa->2d-table d2) (let ((v (make-vector 1024 #f)))
(vector-set! v 305 1)
(vector-set! v 306 1)
(vector-set! v 307 2)
(vector-set! v 561 3)
v))
((dfa->1d-table d1) (make-vector 1 #f))
((dfa->1d-table d2) #(#f
#(#(49 50 1) #(51 51 2))
#(#(49 49 3))
#f))
((dfa->1d-table d3) #(#f
#(#(49 50 1) #(51 51 2) #(100 200 0))
#(#(49 49 3))
#f))
((dfa->actions d1) (vector #f))
((dfa->actions d2) (vector #f #f 2 3))
((dfa->no-look d1) (vector #t))
((dfa->no-look d2) (vector #t #f #f #t)))
;; build-lexer : syntax-object list ->
;; (values table nat (vector-of (union #f syntax-object)) (vector-of bool) (list-of syntax-object))
;; each syntax object has the form (re action)
(define (build-lexer sos)
(define s-re-acts (for/list ([so (in-list sos)])
(cons (parse (stx-car so))
(stx-car (stx-cdr so)))))
(define cache (make-cache))
(define re-acts (for/list ([s-re-act (in-list s-re-acts)])
(cons (->re (car s-re-act) cache)
(cdr s-re-act))))
(define dfa (build-dfa re-acts cache))
(define table (dfa->1d-table dfa))
;(print-dfa dfa)
#;(let ((num-states (vector-length table))
(num-vectors (length (filter values (vector->list table))))
(num-entries (apply + (map
(λ (x) (if x (vector-length x) 0))
(vector->list table))))
(num-different-entries
(let ((ht (make-hash)))
(for-each
(λ (x)
(when x
(for-each
(λ (y)
(hash-set! ht y #t))
(vector->list x))))
(vector->list table))
(length (hash-table-map ht cons)))))
(printf "~a states, ~aKB\n"
num-states
(/ (* 4.0 (+ 2 num-states (* 2 num-vectors) num-entries
(* 5 num-different-entries))) 1024)))
(values table (dfa-start-state dfa) (dfa->actions dfa) (dfa->no-look dfa)))

384
br-parser-tools-lib/br-parser-tools/private-lex/re.rkt
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@ -1,384 +0,0 @@
#lang racket/base
(require racket/list
racket/match
(prefix-in is: data/integer-set)
"util.rkt")
(provide ->re build-epsilon build-zero build-char-set build-concat
build-repeat build-or build-and build-neg
epsilonR? zeroR? char-setR? concatR? repeatR? orR? andR? negR?
char-setR-chars concatR-re1 concatR-re2 repeatR-re repeatR-low repeatR-high
orR-res andR-res negR-re
re-nullable? re-index)
;; get-index : -> nat
(define get-index (make-counter))
;; An re is either
;; - (make-epsilonR bool nat)
;; - (make-zeroR bool nat)
;; - (make-char-setR bool nat char-set)
;; - (make-concatR bool nat re re)
;; - (make-repeatR bool nat nat nat-or-+inf.0 re)
;; - (make-orR bool nat (list-of re)) Must not directly contain any orRs
;; - (make-andR bool nat (list-of re)) Must not directly contain any andRs
;; - (make-negR bool nat re)
;;
;; Every re must have an index field globally different from all
;; other re index fields.
(define-struct re (nullable? index) #:inspector (make-inspector))
(define-struct (epsilonR re) () #:inspector (make-inspector))
(define-struct (zeroR re) () #:inspector (make-inspector))
(define-struct (char-setR re) (chars) #:inspector (make-inspector))
(define-struct (concatR re) (re1 re2) #:inspector (make-inspector))
(define-struct (repeatR re) (low high re) #:inspector (make-inspector))
(define-struct (orR re) (res) #:inspector (make-inspector))
(define-struct (andR re) (res) #:inspector (make-inspector))
(define-struct (negR re) (re) #:inspector (make-inspector))
;; e : re
;; The unique epsilon re
(define e (make-epsilonR #t (get-index)))
;; z : re
;; The unique zero re
(define z (make-zeroR #f (get-index)))
;; s-re = char constant
;; | string constant (sequence of characters)
;; | re a precompiled re
;; | (repetition low high s-re) repetition between low and high times (inclusive)
;; | (union s-re ...)
;; | (intersection s-re ...)
;; | (complement s-re)
;; | (concatenation s-re ...)
;; | (char-range rng rng) match any character between two (inclusive)
;; | (char-complement char-set) match any character not listed
;; low = natural-number
;; high = natural-number or +inf.0
;; rng = char or string with length 1
;; (concatenation) (repetition 0 0 x), and "" match the empty string.
;; (union) matches no strings.
;; (intersection) matches any string.
(define loc:make-range is:make-range)
(define loc:union is:union)
(define loc:split is:split)
(define loc:complement is:complement)
;; ->re : s-re cache -> re
(define (->re exp cache)
(match exp
[(? char?) (build-char-set (loc:make-range (char->integer exp)) cache)]
[(? string?) (->re `(concatenation ,@(string->list exp)) cache)]
[(? re?) exp]
[`(repetition ,low ,high ,r)
(build-repeat low high (->re r cache) cache)]
[`(union ,rs ...)
(build-or (flatten-res (map (λ (r) (->re r cache)) rs)
orR? orR-res loc:union cache)
cache)]
[`(intersection ,rs ...)
(build-and (flatten-res (map (λ (r) (->re r cache)) rs)
andR? andR-res (λ (a b)
(let-values (((i _ __) (loc:split a b))) i))
cache)
cache)]
[`(complement ,r) (build-neg (->re r cache) cache)]
[`(concatenation ,rs ...)
(foldr (λ (x y)
(build-concat (->re x cache) y cache))
e
rs)]
[`(char-range ,c1 ,c2)
(let ([i1 (char->integer (if (string? c1) (string-ref c1 0) c1))]
[i2 (char->integer (if (string? c2) (string-ref c2 0) c2))])
(if (<= i1 i2)
(build-char-set (loc:make-range i1 i2) cache)
z))]
[`(char-complement ,crs ...)
(let ([cs (->re `(union ,@crs) cache)])
(cond
[(zeroR? cs) (build-char-set (loc:make-range 0 max-char-num) cache)]
[(char-setR? cs)
(build-char-set (loc:complement (char-setR-chars cs) 0 max-char-num) cache)]
[else z]))]))
;; flatten-res: (list-of re) (re -> bool) (re -> (list-of re))
;; (char-set char-set -> char-set) cache -> (list-of re)
;; Takes all the char-sets in l and combines them into one char-set using the combine function.
;; Flattens out the values of type?. get-res only needs to function on things type? returns
;; true for.
(define (flatten-res l type? get-res combine cache)
(let loop ([res l]
;; chars : (union #f char-set)
[chars #f]
[no-chars null])
(cond
[(null? res)
(if chars
(cons (build-char-set chars cache) no-chars)
no-chars)]
[(char-setR? (car res))
(if chars
(loop (cdr res) (combine (char-setR-chars (car res)) chars) no-chars)
(loop (cdr res) (char-setR-chars (car res)) no-chars))]
[(type? (car res))
(loop (append (get-res (car res)) (cdr res)) chars no-chars)]
[else (loop (cdr res) chars (cons (car res) no-chars))])))
;; build-epsilon : -> re
(define (build-epsilon) e)
(define (build-zero) z)
(define loc:integer-set-contents is:integer-set-contents)
;; build-char-set : char-set cache -> re
(define (build-char-set cs cache)
(define l (loc:integer-set-contents cs))
(cond
[(null? l) z]
[else
(cache l
(λ ()
(make-char-setR #f (get-index) cs)))]))
;; build-concat : re re cache -> re
(define (build-concat r1 r2 cache)
(cond
[(eq? e r1) r2]
[(eq? e r2) r1]
[(or (eq? z r1) (eq? z r2)) z]
[else
(cache (cons 'concat (cons (re-index r1) (re-index r2)))
(λ ()
(make-concatR (and (re-nullable? r1) (re-nullable? r2))
(get-index)
r1 r2)))]))
;; build-repeat : nat nat-or-+inf.0 re cache -> re
(define (build-repeat low high r cache)
(let ([low (if (< low 0) 0 low)])
(cond
[(eq? r e) e]
[(and (= 0 low) (or (= 0 high) (eq? z r))) e]
[(and (= 1 low) (= 1 high)) r]
[(and (repeatR? r)
(eqv? (repeatR-high r) +inf.0)
(or (= 0 (repeatR-low r))
(= 1 (repeatR-low r))))
(build-repeat (* low (repeatR-low r))
+inf.0
(repeatR-re r)
cache)]
[else
(cache (cons 'repeat (cons low (cons high (re-index r))))
(λ ()
(make-repeatR (or (re-nullable? r) (= 0 low)) (get-index) low high r)))])))
;; build-or : (list-of re) cache -> re
(define (build-or rs cache)
(let ([rs
(filter
(λ (x) (not (eq? x z)))
(do-simple-equiv (replace rs orR? orR-res null) re-index))])
(cond
[(null? rs) z]
[(null? (cdr rs)) (car rs)]
[(memq (build-neg z cache) rs) (build-neg z cache)]
[else
(cache (cons 'or (map re-index rs))
(λ ()
(make-orR (ormap re-nullable? rs) (get-index) rs)))])))
;; build-and : (list-of re) cache -> re
(define (build-and rs cache)
(let ([rs (do-simple-equiv (replace rs andR? andR-res null) re-index)])
(cond
[(null? rs) (build-neg z cache)]
[(null? (cdr rs)) (car rs)]
[(memq z rs) z]
[else
(cache (cons 'and (map re-index rs))
(λ ()
(make-andR (andmap re-nullable? rs) (get-index) rs)))])))
;; build-neg : re cache -> re
(define (build-neg r cache)
(cond
[(negR? r) (negR-re r)]
[else
(cache (cons 'neg (re-index r))
(λ ()
(make-negR (not (re-nullable? r)) (get-index) r)))]))
;; Tests for the build-functions
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r1 (build-char-set (is:make-range (char->integer #\1)) c))
(r2 (build-char-set (is:make-range (char->integer #\2)) c))
(r3 (build-char-set (is:make-range (char->integer #\3)) c))
(rc (build-concat r1 r2 c))
(rc2 (build-concat r2 r1 c))
(rr (build-repeat 0 +inf.0 rc c))
(ro (build-or `(,rr ,rc ,rr) c))
(ro2 (build-or `(,rc ,rr ,z) c))
(ro3 (build-or `(,rr ,rc) c))
(ro4 (build-or `(,(build-or `(,r1 ,r2) c)
,(build-or `(,r2 ,r3) c)) c))
(ra (build-and `(,rr ,rc ,rr) c))
(ra2 (build-and `(,rc ,rr) c))
(ra3 (build-and `(,rr ,rc) c))
(ra4 (build-and `(,(build-and `(,r3 ,r2) c)
,(build-and `(,r2 ,r1) c)) c))
(rn (build-neg z c))
(rn2 (build-neg r1 c)))
((isc (char-setR-chars r1)) (isc (is:make-range (char->integer #\1))))
((isc (char-setR-chars r2)) (isc (is:make-range (char->integer #\2))))
((isc (char-setR-chars r3)) (isc (is:make-range (char->integer #\3))))
((build-char-set (is:make-range) c) z)
((build-concat r1 e c) r1)
((build-concat e r1 c) r1)
((build-concat r1 z c) z)
((build-concat z r1 c) z)
((build-concat r1 r2 c) rc)
((concatR-re1 rc) r1)
((concatR-re2 rc) r2)
((concatR-re1 rc2) r2)
((concatR-re2 rc2) r1)
(ro ro2)
(ro ro3)
(ro4 (build-or `(,r1 ,r2 ,r3) c))
((orR-res ro) (list rc rr))
((orR-res ro4) (list r1 r2 r3))
((build-or null c) z)
((build-or `(,r1 ,z) c) r1)
((build-repeat 0 +inf.0 rc c) rr)
((build-repeat 0 1 z c) e)
((build-repeat 0 0 rc c) e)
((build-repeat 0 +inf.0 z c) e)
((build-repeat -1 +inf.0 z c) e)
((build-repeat 0 +inf.0 (build-repeat 0 +inf.0 rc c) c)
(build-repeat 0 +inf.0 rc c))
((build-repeat 20 20 (build-repeat 0 +inf.0 rc c) c)
(build-repeat 0 +inf.0 rc c))
((build-repeat 20 20 (build-repeat 1 +inf.0 rc c) c)
(build-repeat 20 +inf.0 rc c))
((build-repeat 1 1 rc c) rc)
((repeatR-re rr) rc)
(ra ra2)
(ra ra3)
(ra4 (build-and `(,r1 ,r2 ,r3) c))
((andR-res ra) (list rc rr))
((andR-res ra4) (list r1 r2 r3))
((build-and null c) (build-neg z c))
((build-and `(,r1 ,z) c) z)
((build-and `(,r1) c) r1)
((build-neg r1 c) (build-neg r1 c))
((build-neg (build-neg r1 c) c) r1)
((negR-re (build-neg r2 c)) r2)
((re-nullable? r1) #f)
((re-nullable? rc) #f)
((re-nullable? (build-concat rr rr c)) #t)
((re-nullable? rr) #t)
((re-nullable? (build-repeat 0 1 rc c)) #t)
((re-nullable? (build-repeat 1 2 rc c)) #f)
((re-nullable? (build-repeat 1 2 (build-or (list e r1) c) c)) #t)
((re-nullable? ro) #t)
((re-nullable? (build-or `(,r1 ,r2) c)) #f)
((re-nullable? (build-and `(,r1 ,e) c)) #f)
((re-nullable? (build-and `(,rr ,e) c)) #t)
((re-nullable? (build-neg r1 c)) #t)
((re-nullable? (build-neg rr c)) #f))
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r1 (->re #\1 c))
(r2 (->re #\2 c))
(r3-5 (->re '(char-range #\3 #\5) c))
(r4 (build-or `(,r1 ,r2) c))
(r5 (->re `(union ,r3-5 #\7) c))
(r6 (->re #\6 c)))
((flatten-res null orR? orR-res is:union c) null)
((isc (char-setR-chars (car (flatten-res `(,r1) orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1))))
((isc (char-setR-chars (car (flatten-res `(,r4) orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1) (char->integer #\2))))
((isc (char-setR-chars (car (flatten-res `(,r6 ,r5 ,r4 ,r3-5 ,r2 ,r1)
orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1) (char->integer #\7))))
((flatten-res `(,r1 ,r2) andR? andR-res (λ (x y)
(let-values (((i _ __)
(is:split x y)))
i))
c)
(list z)))
;; ->re
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r (->re #\a c))
(rr (->re `(concatenation ,r ,r) c))
(rrr (->re `(concatenation ,r ,rr) c))
(rrr* (->re `(repetition 0 +inf.0 ,rrr) c)))
((isc (char-setR-chars r)) (isc (is:make-range (char->integer #\a))))
((->re "" c) e)
((->re "asdf" c) (->re `(concatenation #\a #\s #\d #\f) c))
((->re r c) r)
((->re `(repetition 0 +inf.0 ,r) c) (build-repeat 0 +inf.0 r c))
((->re `(repetition 1 +inf.0 ,r) c) (build-repeat 1 +inf.0 r c))
((->re `(repetition 0 1 ,r) c) (build-repeat 0 1 r c))
((->re `(repetition 0 1 ,rrr*) c) rrr*)
((->re `(union (union (char-range #\a #\c)
(char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(union (repetition 0 +inf.0 #\2))) c)
(build-or (list (build-char-set (is:union (is:make-range 73)
(is:make-range 97 99))
c)
(build-repeat 0 +inf.0 (build-char-set (is:make-range 50) c) c))
c))
((->re `(union ,rr ,rrr) c) (build-or (list rr rrr) c))
((->re `(union ,r) c) r)
((->re `(union) c) z)
((->re `(intersection (intersection #\111
(char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(intersection (repetition 0 +inf.0 #\2))) c)
(build-and (list (build-char-set (is:make-range 73) c)
(build-repeat 0 +inf.0 (build-char-set (is:make-range 50) c) c))
c))
((->re `(intersection (intersection #\000 (char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(intersection (repetition 0 +inf.0 #\2))) c)
z)
((->re `(intersection ,rr ,rrr) c) (build-and (list rr rrr) c))
((->re `(intersection ,r) c) r)
((->re `(intersection) c) (build-neg z c))
((->re `(complement ,r) c) (build-neg r c))
((->re `(concatenation) c) e)
((->re `(concatenation ,rrr*) c) rrr*)
(rr (build-concat r r c))
((->re `(concatenation ,r ,rr ,rrr) c)
(build-concat r (build-concat rr rrr c) c))
((isc (char-setR-chars (->re `(char-range #\1 #\1) c))) (isc (is:make-range 49)))
((isc (char-setR-chars (->re `(char-range #\1 #\9) c))) (isc (is:make-range 49 57)))
((isc (char-setR-chars (->re `(char-range "1" "1") c))) (isc (is:make-range 49)))
((isc (char-setR-chars (->re `(char-range "1" "9") c))) (isc (is:make-range 49 57)))
((->re `(char-range "9" "1") c) z)
((isc (char-setR-chars (->re `(char-complement) c)))
(isc (char-setR-chars (->re `(char-range #\000 ,(integer->char max-char-num)) c))))
((isc (char-setR-chars (->re `(char-complement #\001 (char-range #\002 ,(integer->char max-char-num))) c)))
(isc (is:make-range 0)))
)

183
br-parser-tools-lib/br-parser-tools/private-lex/stx.rkt
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#lang racket/base
(require "util.rkt" syntax/id-table racket/syntax)
(provide parse)
(define (bad-args stx num)
(raise-syntax-error #f (format "incorrect number of arguments (should have ~a)" num) stx))
;; char-range-arg: syntax-object syntax-object -> nat
;; If c contains is a character or length 1 string, returns the integer
;; for the character. Otherwise raises a syntax error.
(define (char-range-arg stx containing-stx)
(define c (syntax-e stx))
(cond
[(char? c) (char->integer c)]
[(and (string? c) (= (string-length c) 1))
(char->integer (string-ref c 0))]
[else
(raise-syntax-error
#f
"not a char or single-char string"
containing-stx stx)]))
(module+ test
(check-equal? (char-range-arg #'#\1 #'here) (char->integer #\1))
(check-equal? (char-range-arg #'"1" #'here) (char->integer #\1)))
(define orig-insp (variable-reference->module-declaration-inspector
(#%variable-reference)))
(define (disarm stx)
(syntax-disarm stx orig-insp))
;; parse : syntax-object (box (list-of syntax-object)) -> s-re (see re.rkt)
;; checks for errors and generates the plain s-exp form for s
;; Expands lex-abbrevs and applies lex-trans.
(define (parse stx)
(let loop ([stx stx]
;; seen-lex-abbrevs: id-table
[seen-lex-abbrevs (make-immutable-free-id-table)])
(let ([recur (λ (s)
(loop (syntax-rearm s stx)
seen-lex-abbrevs))]
[recur/abbrev (λ (s id)
(loop (syntax-rearm s stx)
(free-id-table-set seen-lex-abbrevs id id)))])
(syntax-case (disarm stx) (repetition union intersection complement concatenation
char-range char-complement)
[_
(identifier? stx)
(let ([expansion (syntax-local-value/record stx (λ (v) #t))])
(unless (lex-abbrev? expansion)
(raise-syntax-error 'regular-expression
"undefined abbreviation"
stx))
;; Check for cycles.
(when (free-id-table-ref seen-lex-abbrevs stx (λ () #f))
(raise-syntax-error 'regular-expression
"illegal lex-abbrev cycle detected"
stx
#f
(list (free-id-table-ref seen-lex-abbrevs stx))))
(recur/abbrev ((lex-abbrev-get-abbrev expansion)) stx))]
[_
(or (char? (syntax-e stx)) (string? (syntax-e stx)))
(syntax-e stx)]
[(repetition ARG ...)
(let ([arg-list (syntax->list #'(ARG ...))])
(unless (= 3 (length arg-list))
(bad-args stx 2))
(define low (syntax-e (car arg-list)))
(define high (syntax-e (cadr arg-list)))
(define re (caddr arg-list))
(unless (and (number? low) (exact? low) (integer? low) (>= low 0))
(raise-syntax-error #f "not a non-negative exact integer" stx (car arg-list)))
(unless (or (and (number? high) (exact? high) (integer? high) (>= high 0))
(eqv? high +inf.0))
(raise-syntax-error #f "not a non-negative exact integer or +inf.0" stx (cadr arg-list)))
(unless (<= low high)
(raise-syntax-error #f "the first argument is not less than or equal to the second argument" stx))
`(repetition ,low ,high ,(recur re)))]
[(union RE ...)
`(union ,@(map recur (syntax->list #'(RE ...))))]
[(intersection RE ...)
`(intersection ,@(map recur (syntax->list #'(RE ...))))]
[(complement RE ...)
(let ([re-list (syntax->list #'(RE ...))])
(unless (= 1 (length re-list))
(bad-args stx 1))
`(complement ,(recur (car re-list))))]
[(concatenation RE ...)
`(concatenation ,@(map recur (syntax->list #'(RE ...))))]
[(char-range ARG ...)
(let ((arg-list (syntax->list #'(ARG ...))))
(unless (= 2 (length arg-list))
(bad-args stx 2))
(let ([i1 (char-range-arg (car arg-list) stx)]
[i2 (char-range-arg (cadr arg-list) stx)])
(if (<= i1 i2)
`(char-range ,(integer->char i1) ,(integer->char i2))
(raise-syntax-error #f "the first argument does not precede or equal second argument" stx))))]
[(char-complement ARG ...)
(let ([arg-list (syntax->list #'(ARG ...))])
(unless (= 1 (length arg-list))
(bad-args stx 1))
(define parsed (recur (car arg-list)))
(unless (char-set? parsed)
(raise-syntax-error #f "not a character set" stx (car arg-list)))
`(char-complement ,parsed))]
((OP form ...)
(identifier? #'OP)
(let* ([expansion (syntax-local-value/record #'OP (λ (v) #t))])
(cond
[(lex-trans? expansion)
(recur ((lex-trans-f expansion) (disarm stx)))]
[expansion
(raise-syntax-error 'regular-expression "not a lex-trans" stx)]
[else
(raise-syntax-error 'regular-expression "undefined operator" stx)])))
[_ (raise-syntax-error 'regular-expression "not a char, string, identifier, or (op args ...)" stx)]))))
;; char-set? : s-re -> bool
;; A char-set is an re that matches only strings of length 1.
;; char-set? is conservative.
(define (char-set? s-re)
(cond
[(char? s-re)]
[(string? s-re) (= (string-length s-re) 1)]
[(list? s-re) (case (car s-re)
[(union intersection) (andmap char-set? (cdr s-re))]
[(char-range char-complement) #t]
[(repetition) (and (= 1 (cadr s-re) (caddr s-re)) (char-set? (cadddr s-re)))]
[(concatenation) (and (= 2 (length s-re)) (char-set? (cadr s-re)))]
(else #f))]
[else #f]))
(module+ test
(require rackunit)
(check-equal? (char-set? #\a) #t)
(check-equal? (char-set? "12") #f)
(check-equal? (char-set? "1") #t)
(check-equal? (char-set? '(repetition 1 2 #\1)) #f)
(check-equal? (char-set? '(repetition 1 1 "12")) #f)
(check-equal? (char-set? '(repetition 1 1 "1")) #t)
(check-equal? (char-set? '(repetition 6 6 "1")) #f)
(check-equal? (char-set? '(union "1" "2" "3")) #t)
(check-equal? (char-set? '(union "1" "" "3")) #f)
(check-equal? (char-set? '(intersection "1" "2" (union "3" "4"))) #t)
(check-equal? (char-set? '(intersection "1" "")) #f)
(check-equal? (char-set? '(complement "1")) #f)
(check-equal? (char-set? '(concatenation "1" "2")) #f)
(check-equal? (char-set? '(concatenation "" "2")) #f)
(check-equal? (char-set? '(concatenation "1")) #t)
(check-equal? (char-set? '(concatenation "12")) #f)
(check-equal? (char-set? '(char-range #\1 #\2)) #t)
(check-equal? (char-set? '(char-complement #\1)) #t))
;; yikes... these test cases all have the wrong arity, now.
;; and by "now", I mean it's been broken since before we
;; moved to git.
(module+ test
(check-equal? (parse #'#\a) #\a)
(check-equal? (parse #'"1") "1")
(check-equal? (parse #'(repetition 1 1 #\1))
'(repetition 1 1 #\1))
(check-equal? (parse #'(repetition 0 +inf.0 #\1)) '(repetition 0 +inf.0 #\1))
(check-equal? (parse #'(union #\1 (union "2") (union)))
'(union #\1 (union "2") (union)))
(check-equal? (parse #'(intersection #\1 (intersection "2") (intersection)))
'(intersection #\1 (intersection "2") (intersection)))
(check-equal? (parse #'(complement (union #\1 #\2)))
'(complement (union #\1 #\2)))
(check-equal? (parse #'(concatenation "1" "2" (concatenation)))
'(concatenation "1" "2" (concatenation)))
(check-equal? (parse #'(char-range "1" #\1)) '(char-range #\1 #\1))
(check-equal? (parse #'(char-range #\1 "1")) '(char-range #\1 #\1))
(check-equal? (parse #'(char-range "1" "3")) '(char-range #\1 #\3))
(check-equal? (parse #'(char-complement (union "1" "2")))
'(char-complement (union "1" "2")))
(check-equal? (parse #'(char-complement (repetition 1 1 "1")))
'(char-complement (repetition 1 1 "1")))
(check-exn #rx"not a character set"
(λ () (parse #'(char-complement (repetition 6 6 "1"))))))

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br-parser-tools-lib/br-parser-tools/private-lex/token-syntax.rkt
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#lang racket/base
(provide make-terminals-def terminals-def-t terminals-def?
make-e-terminals-def e-terminals-def-t e-terminals-def?)
;; The things needed at compile time to handle definition of tokens
(define-struct terminals-def (t))
(define-struct e-terminals-def (t))

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br-parser-tools-lib/br-parser-tools/private-lex/token.rkt
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#lang racket/base
(require (for-syntax racket/base "token-syntax.rkt"))
;; Defining tokens
(provide define-tokens define-empty-tokens make-token token?
(protect-out (rename-out [token-name real-token-name]))
(protect-out (rename-out [token-value real-token-value]))
(rename-out [token-name* token-name][token-value* token-value])
(struct-out position)
(struct-out position-token)
(struct-out srcloc-token))
;; A token is either
;; - symbol
;; - (make-token symbol any)
(define-struct token (name value) #:inspector (make-inspector))
;; token-name*: token -> symbol
(define (token-name* t)
(cond
[(symbol? t) t]
[(token? t) (token-name t)]
[else (raise-type-error 'token-name "symbol or struct:token" 0 t)]))
;; token-value*: token -> any
(define (token-value* t)
(cond
[(symbol? t) #f]
[(token? t) (token-value t)]
[else (raise-type-error 'token-value "symbol or struct:token" 0 t)]))
(define-for-syntax (make-ctor-name n)
(datum->syntax n
(string->symbol (format "token-~a" (syntax-e n)))
n
n))
(define-for-syntax ((make-define-tokens empty?) stx)
(syntax-case stx ()
[(_ NAME (TOKEN ...))
(andmap identifier? (syntax->list #'(TOKEN ...)))
(with-syntax (((marked-token ...)
(map values #;(make-syntax-introducer)
(syntax->list #'(TOKEN ...)))))
(quasisyntax/loc stx
(begin
(define-syntax NAME
#,(if empty?
#'(make-e-terminals-def (quote-syntax (marked-token ...)))
#'(make-terminals-def (quote-syntax (marked-token ...)))))
#,@(map
(λ (n)
(when (eq? (syntax-e n) 'error)
(raise-syntax-error
#f
"Cannot define a token named error."
stx))
(if empty?
#`(define (#,(make-ctor-name n))
'#,n)
#`(define (#,(make-ctor-name n) x)
(make-token '#,n x))))
(syntax->list #'(TOKEN ...)))
#;(define marked-token #f) #;...)))]
[(_ ...)
(raise-syntax-error #f
"must have the form (define-tokens name (identifier ...)) or (define-empty-tokens name (identifier ...))"
stx)]))
(define-syntax define-tokens (make-define-tokens #f))
(define-syntax define-empty-tokens (make-define-tokens #t))
(define-struct position (offset line col) #:inspector #f)
(define-struct position-token (token start-pos end-pos) #:inspector #f)
(define-struct srcloc-token (token srcloc) #:inspector #f)

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br-parser-tools-lib/br-parser-tools/private-yacc/grammar.rkt
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#lang racket/base
;; Constructs to create and access grammars, the internal
;; representation of the input to the parser generator.
(require racket/class
(except-in racket/list remove-duplicates)
"yacc-helper.rkt"
racket/contract)
;; Each production has a unique index 0 <= index <= number of productions
(define-struct prod (lhs rhs index prec action) #:inspector (make-inspector) #:mutable)
;; The dot-pos field is the index of the element in the rhs
;; of prod that the dot immediately precedes.
;; Thus 0 <= dot-pos <= (vector-length rhs).
(define-struct item (prod dot-pos) #:inspector (make-inspector))
;; gram-sym = (union term? non-term?)
;; Each term has a unique index 0 <= index < number of terms
;; Each non-term has a unique index 0 <= index < number of non-terms
(define-struct term (sym index prec) #:inspector (make-inspector) #:mutable)
(define-struct non-term (sym index) #:inspector (make-inspector) #:mutable)
;; a precedence declaration.
(define-struct prec (num assoc) #:inspector (make-inspector))
(provide/contract
[make-item (prod? (or/c #f natural-number/c) . -> . item?)]
[make-term (symbol? (or/c #f natural-number/c) (or/c prec? #f) . -> . term?)]
[make-non-term (symbol? (or/c #f natural-number/c) . -> . non-term?)]
[make-prec (natural-number/c (or/c 'left 'right 'nonassoc) . -> . prec?)]
[make-prod (non-term? (vectorof (or/c non-term? term?))
(or/c #f natural-number/c) (or/c #f prec?) syntax? . -> . prod?)])
(provide
;; Things that work on items
start-item? item-prod item->string
sym-at-dot move-dot-right item<? item-dot-pos
;; Things that operate on grammar symbols
gram-sym-symbol gram-sym-index term-prec gram-sym->string
non-term? term? non-term<? term<?
term-list->bit-vector term-index non-term-index
;; Things that work on precs
prec-num prec-assoc
grammar%
;; Things that work on productions
prod-index prod-prec prod-rhs prod-lhs prod-action)
;;---------------------- LR items --------------------------
;; item<?: LR-item * LR-item -> bool
;; Lexicographic comparison on two items.
(define (item<? i1 i2)
(define p1 (prod-index (item-prod i1)))
(define p2 (prod-index (item-prod i2)))
(or (< p1 p2)
(and (= p1 p2)
(< (item-dot-pos i1) (item-dot-pos i2)))))
;; start-item?: LR-item -> bool
;; The start production always has index 0
(define (start-item? i)
(zero? (non-term-index (prod-lhs (item-prod i)))))
;; move-dot-right: LR-item -> LR-item | #f
;; moves the dot to the right in the item, unless it is at its
;; rightmost, then it returns false
(define (move-dot-right i)
(cond
[(= (item-dot-pos i) (vector-length (prod-rhs (item-prod i)))) #f]
[else (make-item (item-prod i)
(add1 (item-dot-pos i)))]))
;; sym-at-dot: LR-item -> gram-sym | #f
;; returns the symbol after the dot in the item or #f if there is none
(define (sym-at-dot i)
(define dp (item-dot-pos i))
(define rhs (prod-rhs (item-prod i)))
(cond
[(= dp (vector-length rhs)) #f]
[else (vector-ref rhs dp)]))
;; print-item: LR-item ->
(define (item->string it)
(define print-sym (λ (i)
(let ((gs (vector-ref (prod-rhs (item-prod it)) i)))
(cond
((term? gs) (format "~a " (term-sym gs)))
(else (format "~a " (non-term-sym gs)))))))
(string-append
(format "~a -> " (non-term-sym (prod-lhs (item-prod it))))
(let loop ((i 0))
(cond
[(= i (vector-length (prod-rhs (item-prod it))))
(if (= i (item-dot-pos it))
". "
"")]
[(= i (item-dot-pos it))
(string-append ". " (print-sym i) (loop (add1 i)))]
[else (string-append (print-sym i) (loop (add1 i)))]))))
;; --------------------- Grammar Symbols --------------------------
(define (non-term<? nt1 nt2)
(< (non-term-index nt1) (non-term-index nt2)))
(define (term<? nt1 nt2)
(< (term-index nt1) (term-index nt2)))
(define (gram-sym-index gs)
(if (term? gs)
(term-index gs)
(non-term-index gs)))
(define (gram-sym-symbol gs)
(if (term? gs)
(term-sym gs)
(non-term-sym gs)))
(define (gram-sym->string gs)
(symbol->string (gram-sym-symbol gs)))
;; term-list->bit-vector: term list -> int
;; Creates a number where the nth bit is 1 if the term with index n is in
;; the list, and whose nth bit is 0 otherwise
(define (term-list->bit-vector terms)
(if (null? terms)
0
(bitwise-ior (arithmetic-shift 1 (term-index (car terms)))
(term-list->bit-vector (cdr terms)))))
;; ------------------------- Grammar ------------------------------
(define grammar%
(class object%
(super-instantiate ())
;; prods: production list list
;; where there is one production list per non-term
(init prods)
;; init-prods: production list
;; The productions parsing can start from
;; nullable-non-terms is indexed by the non-term-index and is true iff non-term is nullable
(init-field init-prods terms non-terms end-terms)
;; list of all productions
(define all-prods (apply append prods))
(define num-prods (length all-prods))
(define num-terms (length terms))
(define num-non-terms (length non-terms))
(for ([(nt count) (in-indexed non-terms)])
(set-non-term-index! nt count))
(for ([(t count) (in-indexed terms)])
(set-term-index! t count))
(for ([(prod count) (in-indexed all-prods)])
(set-prod-index! prod count))
;; indexed by the index of the non-term - contains the list of productions for that non-term
(define nt->prods
(let ((v (make-vector (length prods) #f)))
(for ([prods (in-list prods)])
(vector-set! v (non-term-index (prod-lhs (car prods))) prods))
v))
(define nullable-non-terms
(nullable all-prods num-non-terms))
(define/public (get-num-terms) num-terms)
(define/public (get-num-non-terms) num-non-terms)
(define/public (get-prods-for-non-term nt)
(vector-ref nt->prods (non-term-index nt)))
(define/public (get-prods) all-prods)
(define/public (get-init-prods) init-prods)
(define/public (get-terms) terms)
(define/public (get-non-terms) non-terms)
(define/public (get-num-prods) num-prods)
(define/public (get-end-terms) end-terms)
(define/public (nullable-non-term? nt)
(vector-ref nullable-non-terms (non-term-index nt)))
(define/public (nullable-after-dot? item)
(define rhs (prod-rhs (item-prod item)))
(define prod-length (vector-length rhs))
(let loop ((i (item-dot-pos item)))
(cond
[(< i prod-length)
(and (non-term? (vector-ref rhs i))
(nullable-non-term? (vector-ref rhs i))
(loop (add1 i)))]
[(= i prod-length)])))
(define/public (nullable-non-term-thunk)
(λ (nt) (nullable-non-term? nt)))
(define/public (nullable-after-dot?-thunk)
(λ (item) (nullable-after-dot? item)))))
;; nullable: production list * int -> non-term set
;; determines which non-terminals can derive epsilon
(define (nullable prods num-nts)
(define nullable (make-vector num-nts #f))
(define added #f)
;; possible-nullable: producion list -> production list
;; Removes all productions that have a terminal
(define (possible-nullable prods)
(for/list ([prod (in-list prods)]
#:when (vector-andmap non-term? (prod-rhs prod)))
prod))
;; set-nullables: production list -> production list
;; makes one pass through the productions, adding the ones
;; known to be nullable now to nullable and returning a list
;; of productions that we don't know about yet.
(define (set-nullables prods)
(cond
[(null? prods) null]
[(vector-ref nullable (gram-sym-index (prod-lhs (car prods))))
(set-nullables (cdr prods))]
[(vector-andmap (λ (nt) (vector-ref nullable (gram-sym-index nt))) (prod-rhs (car prods)))
(vector-set! nullable (gram-sym-index (prod-lhs (car prods))) #t)
(set! added #t)
(set-nullables (cdr prods))]
[else (cons (car prods) (set-nullables (cdr prods)))]))
(let loop ((P (possible-nullable prods)))
(cond
[(null? P) nullable]
[else
(set! added #f)
(define new-P (set-nullables P))
(if added
(loop new-P)
nullable)])))

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br-parser-tools-lib/br-parser-tools/private-yacc/graph.rkt
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#lang racket/base
(provide digraph)
(define (zero-thunk) 0)
;; digraph:
;; ('a list) * ('a -> 'a list) * ('a -> 'b) * ('b * 'b -> 'b) * (-> 'b)
;; -> ('a -> 'b)
;; DeRemer and Pennello 1982
;; Computes (f x) = (f- x) union Union{(f y) | y in (edges x)}
;; We use a hash-table to represent the result function 'a -> 'b set, so
;; the values of type 'a must be comparable with eq?.
(define (digraph nodes edges f- union fail)
(define results (make-hasheq))
(define (f x) (hash-ref results x fail))
;; Maps elements of 'a to integers.
(define N (make-hasheq))
(define (get-N x) (hash-ref N x zero-thunk))
(define (set-N x d) (hash-set! N x d))
(define stack null)
(define (push x) (set! stack (cons x stack)))
(define (pop) (begin0
(car stack)
(set! stack (cdr stack))))
(define (depth) (length stack))
;; traverse: 'a ->
(define (traverse x)
(push x)
(define d (depth))
(set-N x d)
(hash-set! results x (f- x))
(for-each (λ (y)
(when (= 0 (get-N y))
(traverse y))
(hash-set! results
x
(union (f x) (f y)))
(set-N x (min (get-N x) (get-N y))))
(edges x))
(when (= d (get-N x))
(let loop ([p (pop)])
(set-N p +inf.0)
(hash-set! results p (f x))
(when (not (eq? x p))
(loop (pop))))))
;; Will map elements of 'a to 'b sets
(for ([x (in-list nodes)]
#:when (zero? (get-N x)))
(traverse x))
f)

297
br-parser-tools-lib/br-parser-tools/private-yacc/input-file-parser.rkt
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#lang racket/base
(require "yacc-helper.rkt"
"../private-lex/token-syntax.rkt"
"grammar.rkt"
racket/class
racket/contract
(for-template racket/base))
;; routines for parsing the input to the parser generator and producing a
;; grammar (See grammar.rkt)
(define (is-a-grammar%? x) (is-a? x grammar%))
(provide/contract
[parse-input ((listof identifier?) (listof identifier?) (listof identifier?)
(or/c #f syntax?) syntax? any/c . -> . is-a-grammar%?)]
[get-term-list ((listof identifier?) . -> . (listof identifier?))])
(define stx-for-original-property (read-syntax #f (open-input-string "original")))
;; get-args: ??? -> (values (listof syntax) (or/c #f (cons integer? stx)))
(define (get-args i rhs src-pos term-defs)
(define empty-table (make-hasheq))
(define biggest-pos #f)
(hash-set! empty-table 'error #t)
(for* ([td (in-list term-defs)]
[v (in-value (syntax-local-value td))]
#:when (e-terminals-def? v)
[s (in-list (syntax->list (e-terminals-def-t v)))])
(hash-set! empty-table (syntax->datum s) #t))
(define args
(let get-args ([i i][rhs rhs])
(cond
[(null? rhs) null]
[else
(define b (car rhs))
(define name (if (hash-ref empty-table (syntax->datum (car rhs)) #f)
(gensym)
(string->symbol (format "$~a" i))))
(cond
[src-pos
(define start-pos-id
(datum->syntax b (string->symbol (format "$~a-start-pos" i)) b stx-for-original-property))
(define end-pos-id
(datum->syntax b (string->symbol (format "$~a-end-pos" i)) b stx-for-original-property))
(set! biggest-pos (cons start-pos-id end-pos-id))
(list* (datum->syntax b name b stx-for-original-property)
start-pos-id
end-pos-id
(get-args (add1 i) (cdr rhs)))]
[else
(list* (datum->syntax b name b stx-for-original-property)
(get-args (add1 i) (cdr rhs)))])])))
(values args biggest-pos))
;; Given the list of terminal symbols and the precedence/associativity definitions,
;; builds terminal structures (See grammar.rkt)
;; build-terms: symbol list * symbol list list -> term list
(define (build-terms term-list precs)
(define counter 0)
;;(term-list (cons (gensym) term-list))
;; Will map a terminal symbol to its precedence/associativity
(define prec-table (make-hasheq))
;; Fill the prec table
(for ([p-decl (in-list precs)])
(define assoc (car p-decl))
(for ([term-sym (in-list (cdr p-decl))])
(hash-set! prec-table term-sym (make-prec counter assoc)))
(set! counter (add1 counter)))
;; Build the terminal structures
(for/list ([term-sym (in-list term-list)])
(make-term term-sym
#f
(hash-ref prec-table term-sym (λ () #f)))))
;; Retrieves the terminal symbols from a terminals-def (See terminal-syntax.rkt)
;; get-terms-from-def: identifier? -> (listof identifier?)
(define (get-terms-from-def term-syn)
(define t (syntax-local-value term-syn #f))
(cond
[(terminals-def? t) (syntax->list (terminals-def-t t))]
[(e-terminals-def? t) (syntax->list (e-terminals-def-t t))]
[else
(raise-syntax-error
'parser-tokens
"undefined token group"
term-syn)]))
(define (get-term-list term-group-names)
(remove-duplicates
(cons (datum->syntax #f 'error)
(apply append (map get-terms-from-def term-group-names)))))
(define (parse-input term-defs start ends prec-decls prods src-pos)
(define start-syms (map syntax-e start))
(define list-of-terms (map syntax-e (get-term-list term-defs)))
(define end-terms
(for/list ([end (in-list ends)])
(unless (memq (syntax-e end) list-of-terms)
(raise-syntax-error
'parser-end-tokens
(format "End token ~a not defined as a token"
(syntax-e end))
end))
(syntax-e end)))
;; Get the list of terminals out of input-terms
(define list-of-non-terms
(syntax-case prods ()
[((NON-TERM PRODUCTION ...) ...)
(begin
(for ([nts (in-list (syntax->list #'(NON-TERM ...)))]
#:when (memq (syntax->datum nts) list-of-terms))
(raise-syntax-error
'parser-non-terminals
(format "~a used as both token and non-terminal" (syntax->datum nts))
nts))
(let ([dup (duplicate-list? (syntax->datum #'(NON-TERM ...)))])
(when dup
(raise-syntax-error
'parser-non-terminals
(format "non-terminal ~a defined multiple times" dup)
prods)))
(syntax->datum #'(NON-TERM ...)))]
[_ (raise-syntax-error
'parser-grammar
"Grammar must be of the form (grammar (non-terminal productions ...) ...)"
prods)]))
;; Check the precedence declarations for errors and turn them into data
(define precs
(syntax-case prec-decls ()
[((TYPE TERM ...) ...)
(let ([p-terms (syntax->datum #'(TERM ... ...))])
(cond
[(duplicate-list? p-terms) =>
(λ (d)
(raise-syntax-error
'parser-precedences
(format "duplicate precedence declaration for token ~a" d)
prec-decls))]
[else (for ([t (in-list (syntax->list #'(TERM ... ...)))]
#:when (not (memq (syntax->datum t) list-of-terms)))
(raise-syntax-error
'parser-precedences
(format "Precedence declared for non-token ~a" (syntax->datum t))
t))
(for ([type (in-list (syntax->list #'(TYPE ...)))]
#:unless (memq (syntax->datum type) `(left right nonassoc)))
(raise-syntax-error
'parser-precedences
"Associativity must be left, right or nonassoc"
type))
(syntax->datum prec-decls)]))]
[#f null]
[_ (raise-syntax-error
'parser-precedences
"Precedence declaration must be of the form (precs (assoc term ...) ...) where assoc is left, right or nonassoc"
prec-decls)]))
(define terms (build-terms list-of-terms precs))
(define non-terms (map (λ (non-term) (make-non-term non-term #f))
list-of-non-terms))
(define term-table (make-hasheq))
(define non-term-table (make-hasheq))
(for ([t (in-list terms)])
(hash-set! term-table (gram-sym-symbol t) t))
(for ([nt (in-list non-terms)])
(hash-set! non-term-table (gram-sym-symbol nt) nt))
;; parse-prod: syntax-object -> gram-sym vector
(define (parse-prod prod-so)
(syntax-case prod-so ()
[(PROD-RHS-SYM ...)
(andmap identifier? (syntax->list prod-so))
(begin
(for ([t (in-list (syntax->list prod-so))]
#:when (memq (syntax->datum t) end-terms))
(raise-syntax-error
'parser-production-rhs
(format "~a is an end token and cannot be used in a production" (syntax->datum t))
t))
(for/vector ([s (in-list (syntax->list prod-so))])
(cond
[(hash-ref term-table (syntax->datum s) #f)]
[(hash-ref non-term-table (syntax->datum s) #f)]
[else (raise-syntax-error
'parser-production-rhs
(format "~a is not declared as a terminal or non-terminal" (syntax->datum s))
s)])))]
[_ (raise-syntax-error
'parser-production-rhs
"production right-hand-side must have form (symbol ...)"
prod-so)]))
;; parse-action: syntax-object * syntax-object -> syntax-object
(define (parse-action rhs act-in)
(define-values (args biggest) (get-args 1 (syntax->list rhs) src-pos term-defs))
(define act
(if biggest
(with-syntax ([(CAR-BIGGEST . CDR-BIGGEST) biggest]
[$N-START-POS (datum->syntax (car biggest) '$n-start-pos)]
[$N-END-POS (datum->syntax (cdr biggest) '$n-end-pos)]
[ACT-IN act-in])
#'(let ([$N-START-POS CAR-BIGGEST]
[$N-END-POS CDR-BIGGEST])
ACT-IN))
act-in))
(with-syntax ([ARGS args][ACT act])
(syntax/loc #'ACT (λ ARGS ACT))))
;; parse-prod+action: non-term * syntax-object -> production
(define (parse-prod+action nt prod-so)
(syntax-case prod-so ()
[(PROD-RHS ACTION)
(let ([p (parse-prod #'PROD-RHS)])
(make-prod
nt
p
#f
(let loop ([i (sub1 (vector-length p))])
(if (>= i 0)
(let ([gs (vector-ref p i)])
(if (term? gs)
(term-prec gs)
(loop (sub1 i))))
#f))
(parse-action #'PROD-RHS #'ACTION)))]
[(PROD-RHS (PREC TERM) ACTION)
(identifier? #'TERM)
(let ([p (parse-prod #'PROD-RHS)])
(make-prod
nt
p
#f
(term-prec
(cond
[(hash-ref term-table (syntax->datum #'TERM) #f)]
[else (raise-syntax-error
'parser-production-rhs
(format
"unrecognized terminal ~a in precedence declaration"
(syntax->datum #'TERM))
#'TERM)]))
(parse-action #'PROD-RHS #'ACTION)))]
[_ (raise-syntax-error
'parser-production-rhs
"production must have form [(symbol ...) expression] or [(symbol ...) (prec symbol) expression]"
prod-so)]))
;; parse-prod-for-nt: syntax-object -> production list
(define (parse-prods-for-nt prods-so)
(syntax-case prods-so ()
[(NT PRODUCTIONS ...)
(positive? (length (syntax->list #'(PRODUCTIONS ...))))
(let ([nt (hash-ref non-term-table (syntax->datum #'NT))])
(map (λ (p) (parse-prod+action nt p)) (syntax->list #'(PRODUCTIONS ...))))]
[_ (raise-syntax-error
'parser-productions
"A production for a non-terminal must be (non-term right-hand-side ...) with at least 1 right hand side"
prods-so)]))
(for ([sstx (in-list start)]
[ssym (in-list start-syms)]
#:unless (memq ssym list-of-non-terms))
(raise-syntax-error
'parser-start
(format "Start symbol ~a not defined as a non-terminal" ssym)
sstx))
(define starts (map (λ (x) (make-non-term (gensym) #f)) start-syms))
(define end-non-terms (map (λ (x) (make-non-term (gensym) #f)) start-syms))
(define parsed-prods (map parse-prods-for-nt (syntax->list prods)))
(define start-prods (for/list ([start (in-list starts)]
[end-non-term (in-list end-non-terms)])
(list (make-prod start (vector end-non-term) #f #f #'values))))
(define new-prods
(append start-prods
(for/list ([end-nt (in-list end-non-terms)]
[start-sym (in-list start-syms)])
(for/list ([end (in-list end-terms)])
(make-prod end-nt
(vector
(hash-ref non-term-table start-sym)
(hash-ref term-table end))
#f
#f
#'values)))
parsed-prods))
(make-object grammar%
new-prods
(map car start-prods)
terms
(append starts (append end-non-terms non-terms))
(map (λ (term-name) (hash-ref term-table term-name)) end-terms)))

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br-parser-tools-lib/br-parser-tools/private-yacc/lalr.rkt
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#lang racket/base
(require "lr0.rkt"
"grammar.rkt"
racket/list
racket/class)
;; Compute LALR lookaheads from DeRemer and Pennello 1982
(provide compute-LA)
;; compute-DR: LR0-automaton * grammar -> (trans-key -> term set)
;; computes for each state, non-term transition pair, the terminals
;; which can transition out of the resulting state
;; output term set is represented in bit-vector form
(define ((compute-DR a g) tk)
(define r (send a run-automaton (trans-key-st tk) (trans-key-gs tk)))
(term-list->bit-vector
(filter (λ (term) (send a run-automaton r term)) (send g get-terms))))
;; compute-reads:
;; LR0-automaton * grammar -> (trans-key -> trans-key list)
(define (compute-reads a g)
(define nullable-non-terms (filter (λ (nt) (send g nullable-non-term? nt)) (send g get-non-terms)))
(λ (tk)
(define r (send a run-automaton (trans-key-st tk) (trans-key-gs tk)))
(for/list ([non-term (in-list nullable-non-terms)]
#:when (send a run-automaton r non-term))
(make-trans-key r non-term))))
;; compute-read: LR0-automaton * grammar -> (trans-key -> term set)
;; output term set is represented in bit-vector form
(define (compute-read a g)
(define dr (compute-DR a g))
(define reads (compute-reads a g))
(digraph-tk->terml (send a get-mapped-non-term-keys)
reads
dr
(send a get-num-states)))
;; returns the list of all k such that state k transitions to state start on the
;; transitions in rhs (in order)
(define (run-lr0-backward a rhs dot-pos start num-states)
(let loop ([states (list start)]
[i (sub1 dot-pos)])
(cond
[(< i 0) states]
[else (loop (send a run-automaton-back states (vector-ref rhs i))
(sub1 i))])))
;; prod->items-for-include: grammar * prod * non-term -> lr0-item list
;; returns the list of all (B -> beta . nt gamma) such that prod = (B -> beta nt gamma)
;; and gamma =>* epsilon
(define (prod->items-for-include g prod nt)
(define rhs (prod-rhs prod))
(define rhs-l (vector-length rhs))
(append (if (and (> rhs-l 0) (eq? nt (vector-ref rhs (sub1 rhs-l))))
(list (make-item prod (sub1 rhs-l)))
null)
(let loop ([i (sub1 rhs-l)])
(cond
[(and (> i 0)
(non-term? (vector-ref rhs i))
(send g nullable-non-term? (vector-ref rhs i)))
(if (eq? nt (vector-ref rhs (sub1 i)))
(cons (make-item prod (sub1 i))
(loop (sub1 i)))
(loop (sub1 i)))]
[else null]))))
;; prod-list->items-for-include: grammar * prod list * non-term -> lr0-item list
;; return the list of all (B -> beta . nt gamma) such that (B -> beta nt gamma) in prod-list
;; and gamma =>* epsilon
(define (prod-list->items-for-include g prod-list nt)
(apply append (map (λ (prod) (prod->items-for-include g prod nt)) prod-list)))
;; comput-includes: lr0-automaton * grammar -> (trans-key -> trans-key list)
(define (compute-includes a g)
(define num-states (send a get-num-states))
(define items-for-input-nt (make-vector (send g get-num-non-terms) null))
(for ([input-nt (in-list (send g get-non-terms))])
(vector-set! items-for-input-nt (non-term-index input-nt)
(prod-list->items-for-include g (send g get-prods) input-nt)))
(λ (tk)
(define goal-state (trans-key-st tk))
(define non-term (trans-key-gs tk))
(define items (vector-ref items-for-input-nt (non-term-index non-term)))
(trans-key-list-remove-dups
(apply append
(for/list ([item (in-list items)])
(define prod (item-prod item))
(define rhs (prod-rhs prod))
(define lhs (prod-lhs prod))
(map (λ (state) (make-trans-key state lhs))
(run-lr0-backward a
rhs
(item-dot-pos item)
goal-state
num-states)))))))
;; compute-lookback: lr0-automaton * grammar -> (kernel * proc -> trans-key list)
(define (compute-lookback a g)
(define num-states (send a get-num-states))
(λ (state prod)
(map (λ (k) (make-trans-key k (prod-lhs prod)))
(run-lr0-backward a (prod-rhs prod) (vector-length (prod-rhs prod)) state num-states))))
;; compute-follow: LR0-automaton * grammar -> (trans-key -> term set)
;; output term set is represented in bit-vector form
(define (compute-follow a g includes)
(define read (compute-read a g))
(digraph-tk->terml (send a get-mapped-non-term-keys)
includes
read
(send a get-num-states)))
;; compute-LA: LR0-automaton * grammar -> kernel * prod -> term set
;; output term set is represented in bit-vector form
(define (compute-LA a g)
(define includes (compute-includes a g))
(define lookback (compute-lookback a g))
(define follow (compute-follow a g includes))
(λ (k p)
(define l (lookback k p))
(define f (map follow l))
(apply bitwise-ior (cons 0 f))))
(define (print-DR dr a g)
(print-input-st-sym dr "DR" a g print-output-terms))
(define (print-Read Read a g)
(print-input-st-sym Read "Read" a g print-output-terms))
(define (print-includes i a g)
(print-input-st-sym i "includes" a g print-output-st-nt))
(define (print-lookback l a g)
(print-input-st-prod l "lookback" a g print-output-st-nt))
(define (print-follow f a g)
(print-input-st-sym f "follow" a g print-output-terms))
(define (print-LA l a g)
(print-input-st-prod l "LA" a g print-output-terms))
(define (print-input-st-sym f name a g print-output)
(printf "~a:\n" name)
(send a for-each-state
(λ (state)
(for-each
(λ (non-term)
(let ([res (f (make-trans-key state non-term))])
(when (not (null? res))
(printf "~a(~a, ~a) = ~a\n"
name
state
(gram-sym-symbol non-term)
(print-output res)))))
(send g get-non-terms))))
(newline))
(define (print-input-st-prod f name a g print-output)
(printf "~a:\n" name)
(send a for-each-state
(λ (state)
(for-each
(λ (non-term)
(for-each
(λ (prod)
(let ([res (f state prod)])
(when (not (null? res))
(printf "~a(~a, ~a) = ~a\n"
name
(kernel-index state)
(prod-index prod)
(print-output res)))))
(send g get-prods-for-non-term non-term)))
(send g get-non-terms)))))
(define (print-output-terms r)
(map gram-sym-symbol r))
(define (print-output-st-nt r)
(map (λ (p) (list (kernel-index (trans-key-st p)) (gram-sym-symbol (trans-key-gs p)))) r))
;; init-tk-map : int -> (vectorof hashtable?)
(define (init-tk-map n)
(define v (make-vector n #f))
(let loop ([i (sub1 (vector-length v))])
(when (>= i 0)
(vector-set! v i (make-hasheq))
(loop (sub1 i))))
v)
;; lookup-tk-map : (vectorof (symbol? int hashtable)) -> trans-key? -> int
(define ((lookup-tk-map map) tk)
(define st (trans-key-st tk))
(define gs (trans-key-gs tk))
(hash-ref (vector-ref map (kernel-index st))
(gram-sym-symbol gs)
(λ () 0)))
;; add-tk-map : (vectorof (symbol? int hashtable)) -> trans-key int ->
(define ((add-tk-map map) tk v)
(define st (trans-key-st tk))
(define gs (trans-key-gs tk))
(hash-set! (vector-ref map (kernel-index st))
(gram-sym-symbol gs)
v))
;; digraph-tk->terml:
;; (trans-key list) * (trans-key -> trans-key list) * (trans-key -> term list) * int * int * int
;; -> (trans-key -> term list)
;; DeRemer and Pennello 1982
;; Computes (f x) = (f- x) union Union{(f y) | y in (edges x)}
;; A specialization of digraph in the file graph.rkt
(define (digraph-tk->terml nodes edges f- num-states)
;; Will map elements of trans-key to term sets represented as bit vectors
(define results (init-tk-map num-states))
;; Maps elements of trans-keys to integers.
(define N (init-tk-map num-states))
(define get-N (lookup-tk-map N))
(define set-N (add-tk-map N))
(define get-f (lookup-tk-map results))
(define set-f (add-tk-map results))
(define stack null)
(define (push x) (set! stack (cons x stack)))
(define (pop) (begin0
(car stack)
(set! stack (cdr stack))))
(define (depth) (length stack))
;; traverse: 'a ->
(define (traverse x)
(push x)
(let ([d (depth)])
(set-N x d)
(set-f x (f- x))
(for-each (λ (y)
(when (= 0 (get-N y))
(traverse y))
(set-f x (bitwise-ior (get-f x) (get-f y)))
(set-N x (min (get-N x) (get-N y))))
(edges x))
(when (= d (get-N x))
(let loop ([p (pop)])
(set-N p +inf.0)
(set-f p (get-f x))
(unless (equal? x p)
(loop (pop)))))))
(for ([x (in-list nodes)]
#:when (zero? (get-N x)))
(traverse x))
get-f)

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br-parser-tools-lib/br-parser-tools/private-yacc/lr0.rkt
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#lang racket/base
(require "grammar.rkt"
"graph.rkt"
racket/list
racket/class)
;; Handle the LR0 automaton
(provide build-lr0-automaton lr0%
(struct-out trans-key) trans-key-list-remove-dups
kernel-items kernel-index)
;; kernel = (make-kernel (LR1-item list) index)
;; the list must be kept sorted according to item<? so that equal? can
;; be used to compare kernels
;; Each kernel is assigned a unique index, 0 <= index < number of states
;; trans-key = (make-trans-key kernel gram-sym)
(define-struct kernel (items index) #:inspector (make-inspector))
(define-struct trans-key (st gs) #:inspector (make-inspector))
(define (trans-key<? a b)
(define kia (kernel-index (trans-key-st a)))
(define kib (kernel-index (trans-key-st b)))
(or (< kia kib)
(and (= kia kib)
(< (non-term-index (trans-key-gs a))
(non-term-index (trans-key-gs b))))))
(define (trans-key-list-remove-dups tkl)
(let loop ([sorted (sort tkl trans-key<?)])
(cond
[(null? sorted) null]
[(null? (cdr sorted)) sorted]
[else
(if (and (= (non-term-index (trans-key-gs (car sorted)))
(non-term-index (trans-key-gs (cadr sorted))))
(= (kernel-index (trans-key-st (car sorted)))
(kernel-index (trans-key-st (cadr sorted)))))
(loop (cdr sorted))
(cons (car sorted) (loop (cdr sorted))))])))
;; build-transition-table : int (listof (cons/c trans-key X) ->
;; (vectorof (symbol X hashtable))
(define (build-transition-table num-states assoc)
(define transitions (make-vector num-states #f))
(let loop ([i (sub1 (vector-length transitions))])
(when (>= i 0)
(vector-set! transitions i (make-hasheq))
(loop (sub1 i))))
(for ([trans-key/kernel (in-list assoc)])
(define tk (car trans-key/kernel))
(hash-set! (vector-ref transitions (kernel-index (trans-key-st tk)))
(gram-sym-symbol (trans-key-gs tk))
(cdr trans-key/kernel)))
transitions)
;; reverse-assoc : (listof (cons/c trans-key? kernel?)) ->
;; (listof (cons/c trans-key? (listof kernel?)))
(define (reverse-assoc assoc)
(define reverse-hash (make-hash))
(define (hash-table-add! ht k v)
(hash-set! ht k (cons v (hash-ref ht k (λ () null)))))
(for ([trans-key/kernel (in-list assoc)])
(define tk (car trans-key/kernel))
(hash-table-add! reverse-hash
(make-trans-key (cdr trans-key/kernel)
(trans-key-gs tk))
(trans-key-st tk)))
(hash-map reverse-hash cons))
;; kernel-list-remove-duplicates
;; LR0-automaton = object of class lr0%
(define lr0%
(class object%
(super-instantiate ())
;; term-assoc : (listof (cons/c trans-key? kernel?))
;; non-term-assoc : (listof (cons/c trans-key? kernel?))
;; states : (vectorof kernel?)
;; epsilons : ???
(init-field term-assoc non-term-assoc states epsilons)
(define transitions (build-transition-table (vector-length states)
(append term-assoc non-term-assoc)))
(define reverse-term-assoc (reverse-assoc term-assoc))
(define reverse-non-term-assoc (reverse-assoc non-term-assoc))
(define reverse-transitions
(build-transition-table (vector-length states)
(append reverse-term-assoc reverse-non-term-assoc)))
(define mapped-non-terms (map car non-term-assoc))
(define/public (get-mapped-non-term-keys)
mapped-non-terms)
(define/public (get-num-states)
(vector-length states))
(define/public (get-epsilon-trans)
epsilons)
(define/public (get-transitions)
(append term-assoc non-term-assoc))
;; for-each-state : (state ->) ->
;; Iteration over the states in an automaton
(define/public (for-each-state f)
(define num-states (vector-length states))
(let loop ([i 0])
(when (< i num-states)
(f (vector-ref states i))
(loop (add1 i)))))
;; run-automaton: kernel? gram-sym? -> (union kernel #f)
;; returns the state reached from state k on input s, or #f when k
;; has no transition on s
(define/public (run-automaton k s)
(hash-ref (vector-ref transitions (kernel-index k))
(gram-sym-symbol s)
(λ () #f)))
;; run-automaton-back : (listof kernel?) gram-sym? -> (listof kernel)
;; returns the list of states that can reach k by transitioning on s.
(define/public (run-automaton-back k s)
(for*/list ([k (in-list k)]
[val (in-list (hash-ref (vector-ref reverse-transitions (kernel-index k))
(gram-sym-symbol s)
(λ () null)))])
val))))
(define ((union comp<?) l1 l2)
(let loop ([l1 l1] [l2 l2])
(cond
[(null? l1) l2]
[(null? l2) l1]
[else (define c1 (car l1))
(define c2 (car l2))
(cond
[(comp<? c1 c2) (cons c1 (loop (cdr l1) l2))]
[(comp<? c2 c1) (cons c2 (loop l1 (cdr l2)))]
[else (loop (cdr l1) l2)])])))
;; The kernels in the automaton are represented cannonically.
;; That is (equal? a b) <=> (eq? a b)
(define (kernel->string k)
(apply string-append
`("{" ,@(map (λ (i) (string-append (item->string i) ", "))
(kernel-items k))
"}")))
;; build-LR0-automaton: grammar -> LR0-automaton
;; Constructs the kernels of the sets of LR(0) items of g
(define (build-lr0-automaton grammar)
; (printf "LR(0) automaton:\n")
(define epsilons (make-hash))
(define grammar-symbols (append (send grammar get-non-terms)
(send grammar get-terms)))
;; first-non-term: non-term -> non-term list
;; given a non-terminal symbol C, return those non-terminal
;; symbols A s.t. C -> An for some string of terminals and
;; non-terminals n where -> means a rightmost derivation in many
;; steps. Assumes that each non-term can be reduced to a string
;; of terms.
(define first-non-term
(digraph (send grammar get-non-terms)
(λ (nt)
(filter non-term?
(map (λ (prod) (sym-at-dot (make-item prod 0)))
(send grammar get-prods-for-non-term nt))))
(λ (nt) (list nt))
(union non-term<?)
(λ () null)))
;; closure: LR1-item list -> LR1-item list
;; Creates a set of items containing i s.t. if A -> n.Xm is in it,
;; X -> .o is in it too.
(define (LR0-closure i)
(cond
[(null? i) null]
[else
(define next-gsym (sym-at-dot (car i)))
(cond
[(non-term? next-gsym)
(cons (car i)
(append
(for*/list ([non-term (in-list (first-non-term next-gsym))]
[x (in-list (send grammar
get-prods-for-non-term
non-term))])
(make-item x 0))
(LR0-closure (cdr i))))]
[else (cons (car i) (LR0-closure (cdr i)))])]))
;; maps trans-keys to kernels
(define automaton-term null)
(define automaton-non-term null)
;; keeps the kernels we have seen, so we can have a unique
;; list for each kernel
(define kernels (make-hash))
(define counter 0)
;; goto: LR1-item list -> LR1-item list list
;; creates new kernels by moving the dot in each item in the
;; LR0-closure of kernel to the right, and grouping them by
;; the term/non-term moved over. Returns the kernels not
;; yet seen, and places the trans-keys into automaton
(define (goto kernel)
;; maps a gram-syms to a list of items
(define table (make-hasheq))
;; add-item!:
;; (symbol (listof item) hashtable) item? ->
;; adds i into the table grouped with the grammar
;; symbol following its dot
(define (add-item! table i)
(define gs (sym-at-dot i))
(cond
[gs (define already (hash-ref table (gram-sym-symbol gs) (λ () null)))
(unless (member i already)
(hash-set! table (gram-sym-symbol gs) (cons i already)))]
((zero? (vector-length (prod-rhs (item-prod i))))
(define current (hash-ref epsilons kernel (λ () null)))
(hash-set! epsilons kernel (cons i current)))))
;; Group the items of the LR0 closure of the kernel
;; by the character after the dot
(for ([item (in-list (LR0-closure (kernel-items kernel)))])
(add-item! table item))
;; each group is a new kernel, with the dot advanced.
;; sorts the items in a kernel so kernels can be compared
;; with equal? for using the table kernels to make sure
;; only one representitive of each kernel is created
(define is
(let loop ([gsyms grammar-symbols])
(cond
[(null? gsyms) null]
[else
(define items (hash-ref table (gram-sym-symbol (car gsyms)) (λ () null)))
(cond
[(null? items) (loop (cdr gsyms))]
[else (cons (list (car gsyms) items)
(loop (cdr gsyms)))])])))
(filter
values
(for/list ([i (in-list is)])
(define gs (car i))
(define items (cadr i))
(define new #f)
(define new-kernel (sort (filter values (map move-dot-right items)) item<?))
(define unique-kernel (hash-ref kernels new-kernel
(λ ()
(define k (make-kernel new-kernel counter))
(set! new #t)
(set! counter (add1 counter))
(hash-set! kernels new-kernel k)
k)))
(if (term? gs)
(set! automaton-term (cons (cons (make-trans-key kernel gs)
unique-kernel)
automaton-term))
(set! automaton-non-term (cons (cons (make-trans-key kernel gs)
unique-kernel)
automaton-non-term)))
#;(printf "~a -> ~a on ~a\n"
(kernel->string kernel)
(kernel->string unique-kernel)
(gram-sym-symbol gs))
(and new unique-kernel))))
(define starts (map (λ (init-prod) (list (make-item init-prod 0)))
(send grammar get-init-prods)))
(define startk (for/list ([start (in-list starts)])
(define k (make-kernel start counter))
(hash-set! kernels start k)
(set! counter (add1 counter))
k))
(define new-kernels (make-queue))
(let loop ([old-kernels startk]
[seen-kernels null])
(cond
[(and (empty-queue? new-kernels) (null? old-kernels))
(make-object lr0% automaton-term automaton-non-term
(list->vector (reverse seen-kernels)) epsilons)]
[(null? old-kernels) (loop (deq! new-kernels) seen-kernels)]
[else
(enq! new-kernels (goto (car old-kernels)))
(loop (cdr old-kernels) (cons (car old-kernels) seen-kernels))])))
(define-struct q (f l) #:inspector (make-inspector) #:mutable)
(define (empty-queue? q) (null? (q-f q)))
(define (make-queue) (make-q null null))
(define (enq! q i)
(cond
[(empty-queue? q)
(let ([i (mcons i null)])
(set-q-l! q i)
(set-q-f! q i))]
[else
(set-mcdr! (q-l q) (mcons i null))
(set-q-l! q (mcdr (q-l q)))]))
(define (deq! q)
(begin0
(mcar (q-f q))
(set-q-f! q (mcdr (q-f q)))))

54
br-parser-tools-lib/br-parser-tools/private-yacc/parser-actions.rkt
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#lang racket/base
(require "grammar.rkt")
(provide (except-out (all-defined-out) make-reduce make-reduce*)
(rename-out [make-reduce* make-reduce]))
;; An action is
;; - (make-shift int)
;; - (make-reduce prod runtime-action)
;; - (make-accept)
;; - (make-goto int)
;; - (no-action)
;; A reduce contains a runtime-reduce so that sharing of the reduces can
;; be easily transferred to sharing of runtime-reduces.
(define-struct action () #:inspector (make-inspector))
(define-struct (shift action) (state) #:inspector (make-inspector))
(define-struct (reduce action) (prod runtime-reduce) #:inspector (make-inspector))
(define-struct (accept action) () #:inspector (make-inspector))
(define-struct (goto action) (state) #:inspector (make-inspector))
(define-struct (no-action action) () #:inspector (make-inspector))
(define (make-reduce* p)
(make-reduce p
(vector (prod-index p)
(gram-sym-symbol (prod-lhs p))
(vector-length (prod-rhs p)))))
;; A runtime-action is
;; non-negative-int (shift)
;; (vector int symbol int) (reduce)
;; 'accept (accept)
;; negative-int (goto)
;; #f (no-action)
(define (action->runtime-action a)
(cond
[(shift? a) (shift-state a)]
[(reduce? a) (reduce-runtime-reduce a)]
[(accept? a) 'accept]
[(goto? a) (- (+ (goto-state a) 1))]
[(no-action? a) #f]))
(define (runtime-shift? x) (and (integer? x) (>= x 0)))
(define runtime-reduce? vector?)
(define (runtime-accept? x) (eq? x 'accept))
(define (runtime-goto? x) (and (integer? x) (< x 0)))
(define runtime-shift-state values)
(define (runtime-reduce-prod-num x) (vector-ref x 0))
(define (runtime-reduce-lhs x) (vector-ref x 1))
(define (runtime-reduce-rhs-length x) (vector-ref x 2))
(define (runtime-goto-state x) (- (+ x 1)))

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br-parser-tools-lib/br-parser-tools/private-yacc/parser-builder.rkt
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#lang racket/base
(require "input-file-parser.rkt"
"grammar.rkt"
"table.rkt"
racket/class
racket/contract)
(require (for-template racket/base))
(provide/contract [build-parser (-> string? any/c any/c
(listof identifier?)
(listof identifier?)
(listof identifier?)
(or/c syntax? #f)
syntax?
(values any/c any/c any/c any/c))])
;; fix-check-syntax : (listof identifier?) (listof identifier?) (listof identifier?)
;; (union syntax? false/c) syntax?) -> syntax?
(define (fix-check-syntax input-terms start ends assocs prods)
(define term-binders (get-term-list input-terms))
(define get-term-binder
(let ([t (make-hasheq)])
(for ([term (in-list term-binders)])
(hash-set! t (syntax-e term) term))
(λ (x)
(define r (hash-ref t (syntax-e x) (λ () #f)))
(if r
(syntax-local-introduce (datum->syntax r (syntax-e x) x x))
x))))
(define rhs-list (syntax-case prods ()
[((_ RHS ...) ...) (syntax->list #'(RHS ... ...))]))
(with-syntax ([(TMP ...) (map syntax-local-introduce term-binders)]
[(TERM-GROUP ...)
(map (λ (tg)
(syntax-property
(datum->syntax tg #f)
'disappeared-use
tg))
input-terms)]
[(END ...) (map get-term-binder ends)]
[(START ...) (map get-term-binder start)]
[(BIND ...) (syntax-case prods ()
(((BIND _ ...) ...)
(syntax->list #'(BIND ...))))]
[((BOUND ...) ...)
(map (λ (rhs)
(syntax-case rhs ()
[((BOUND ...) (_ PBOUND) __)
(map get-term-binder
(cons #'PBOUND (syntax->list #'(BOUND ...))))]
[((BOUND ...) _)
(map get-term-binder
(syntax->list #'(BOUND ...)))]))
rhs-list)]
[(PREC ...)
(if assocs
(map get-term-binder
(syntax-case assocs ()
(((__ TERM ...) ...)
(syntax->list #'(TERM ... ...)))))
null)])
#`(when #f
(let ((BIND void) ... (TMP void) ...)
(void BOUND ... ... TERM-GROUP ... START ... END ... PREC ...)))))
(require racket/list "parser-actions.rkt")
(define (build-parser filename src-pos suppress input-terms start end assocs prods)
(define grammar (parse-input input-terms start end assocs prods src-pos))
(define table (build-table grammar filename suppress))
(define all-tokens (make-hasheq))
(define actions-code `(vector ,@(map prod-action (send grammar get-prods))))
(for ([term (in-list (send grammar get-terms))])
(hash-set! all-tokens (gram-sym-symbol term) #t))
#;(let ((num-states (vector-length table))
(num-gram-syms (+ (send grammar get-num-terms)
(send grammar get-num-non-terms)))
(num-ht-entries (apply + (map length (vector->list table))))
(num-reduces
(let ((ht (make-hasheq)))
(for-each
(λ (x)
(when (reduce? x)
(hash-set! ht x #t)))
(map cdr (apply append (vector->list table))))
(length (hash-table-map ht void)))))
(printf "~a states, ~a grammar symbols, ~a hash-table entries, ~a reduces\n"
num-states num-gram-syms num-ht-entries num-reduces)
(printf "~a -- ~aKB, previously ~aKB\n"
(/ (+ 2 num-states
(* 4 num-states) (* 2 1.5 num-ht-entries)
(* 5 num-reduces)) 256.0)
(/ (+ 2 num-states
(* 4 num-states) (* 2 2.3 num-ht-entries)
(* 5 num-reduces)) 256.0)
(/ (+ 2 (* num-states num-gram-syms) (* 5 num-reduces)) 256.0)))
(values table
all-tokens
actions-code
(fix-check-syntax input-terms start end assocs prods)))

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br-parser-tools-lib/br-parser-tools/private-yacc/table.rkt
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#lang racket/base
(require "grammar.rkt"
"lr0.rkt"
"lalr.rkt"
"parser-actions.rkt"
racket/contract
racket/list
racket/class)
;; Routine to build the LALR table
(define (is-a-grammar%? x) (is-a? x grammar%))
(provide/contract
(build-table (-> is-a-grammar%? string? any/c
(vectorof (listof (cons/c (or/c term? non-term?) action?))))))
;; A parse-table is (vectorof (listof (cons/c gram-sym? action)))
;; A grouped-parse-table is (vectorof (listof (cons/c gram-sym? (listof action))))
;; make-parse-table : int -> parse-table
(define (make-parse-table num-states)
(make-vector num-states null))
;; table-add!: parse-table nat symbol action ->
(define (table-add! table state-index symbol val)
(vector-set! table state-index (cons (cons symbol val)
(vector-ref table state-index))))
;; group-table : parse-table -> grouped-parse-table
(define (group-table table)
(list->vector
(for/list ([state-entry (in-list (vector->list table))])
(define ht (make-hasheq))
(for* ([gs/actions (in-list state-entry)]
[group (in-value (hash-ref ht (car gs/actions) (λ () null)))]
#:unless (member (cdr gs/actions) group))
(hash-set! ht (car gs/actions) (cons (cdr gs/actions) group)))
(hash-map ht cons))))
;; table-map : (vectorof (listof (cons/c gram-sym? X))) (gram-sym? X -> Y) ->
;; (vectorof (listof (cons/c gram-sym? Y)))
(define (table-map f table)
(list->vector
(for/list ([state-entry (in-list (vector->list table))])
(for/list ([gs/X (in-list state-entry)])
(cons (car gs/X) (f (car gs/X) (cdr gs/X)))))))
(define (bit-vector-for-each f bv)
(let loop ([bv bv] [number 0])
(cond
[(zero? bv) (void)]
[(= 1 (bitwise-and 1 bv))
(f number)
(loop (arithmetic-shift bv -1) (add1 number))]
[else (loop (arithmetic-shift bv -1) (add1 number))])))
;; print-entry: symbol action output-port ->
;; prints the action a for lookahead sym to the given port
(define (print-entry sym a port)
(define s "\t~a\t\t\t\t\t~a\t~a\n")
(cond
[(shift? a) (fprintf port s sym "shift" (shift-state a))]
[(reduce? a) (fprintf port s sym "reduce" (prod-index (reduce-prod a)))]
[(accept? a) (fprintf port s sym "accept" "")]
[(goto? a) (fprintf port s sym "goto" (goto-state a))]))
;; count: ('a -> bool) * 'a list -> num
;; counts the number of elements in list that satisfy pred
(define (count pred list)
(cond
[(null? list) 0]
[(pred (car list)) (+ 1 (count pred (cdr list)))]
[else (count pred (cdr list))]))
;; display-parser: LR0-automaton grouped-parse-table (listof prod?) output-port ->
;; Prints out the parser given by table.
(define (display-parser a grouped-table prods port)
(define SR-conflicts 0)
(define RR-conflicts 0)
(for ([prod (in-list prods)])
(fprintf port
"~a\t~a\t=\t~a\n"
(prod-index prod)
(gram-sym-symbol (prod-lhs prod))
(map gram-sym-symbol (vector->list (prod-rhs prod)))))
(send a for-each-state
(λ (state)
(fprintf port "State ~a\n" (kernel-index state))
(for ([item (in-list (kernel-items state))])
(fprintf port "\t~a\n" (item->string item)))
(newline port)
(for ([gs/action (in-list (vector-ref grouped-table (kernel-index state)))])
(define sym (gram-sym-symbol (car gs/action)))
(define act (cdr gs/action))
(cond
[(null? act) (void)]
[(null? (cdr act))
(print-entry sym (car act) port)]
[else
(fprintf port "begin conflict:\n")
(when (> (count reduce? act) 1)
(set! RR-conflicts (add1 RR-conflicts)))
(when (> (count shift? act) 0)
(set! SR-conflicts (add1 SR-conflicts)))
(map (λ (x) (print-entry sym x port)) act)
(fprintf port "end conflict\n")]))
(newline port)))
(when (> SR-conflicts 0)
(fprintf port "~a shift/reduce conflict~a\n"
SR-conflicts
(if (= SR-conflicts 1) "" "s")))
(when (> RR-conflicts 0)
(fprintf port "~a reduce/reduce conflict~a\n"
RR-conflicts
(if (= RR-conflicts 1) "" "s"))))
;; resolve-conflict : (listof action?) -> action? bool bool
(define (resolve-conflict actions)
(cond
[(null? actions) (values (make-no-action) #f #f)]
[(null? (cdr actions)) (values (car actions) #f #f)]
[else
(define SR-conflict? (> (count shift? actions) 0))
(define RR-conflict? (> (count reduce? actions) 1))
(let loop ((current-guess #f)
(rest actions))
(cond
[(null? rest) (values current-guess SR-conflict? RR-conflict?)]
[(shift? (car rest)) (values (car rest) SR-conflict? RR-conflict?)]
[(not current-guess) (loop (car rest) (cdr rest))]
[(and (reduce? (car rest))
(< (prod-index (reduce-prod (car rest)))
(prod-index (reduce-prod current-guess))))
(loop (car rest) (cdr rest))]
[(accept? (car rest))
(eprintf "accept/reduce or accept/shift conflicts. Check the grammar for useless cycles of productions\n")
(loop current-guess (cdr rest))]
[else (loop current-guess (cdr rest))]))]))
;; resolve-conflicts : grouped-parse-table bool -> parse-table
(define (resolve-conflicts grouped-table suppress)
(define SR-conflicts 0)
(define RR-conflicts 0)
(define table (table-map
(λ (gs actions)
(let-values ([(action SR? RR?)
(resolve-conflict actions)])
(when SR?
(set! SR-conflicts (add1 SR-conflicts)))
(when RR?
(set! RR-conflicts (add1 RR-conflicts)))
action))
grouped-table))
(unless suppress
(when (> SR-conflicts 0)
(eprintf "~a shift/reduce conflict~a\n"
SR-conflicts
(if (= SR-conflicts 1) "" "s")))
(when (> RR-conflicts 0)
(eprintf "~a reduce/reduce conflict~a\n"
RR-conflicts
(if (= RR-conflicts 1) "" "s"))))
table)
;; resolve-sr-conflict : (listof action) (union int #f) -> (listof action)
;; Resolves a single shift-reduce conflict, if precedences are in place.
(define (resolve-sr-conflict/prec actions shift-prec)
(define shift (if (shift? (car actions))
(car actions)
(cadr actions)))
(define reduce (if (shift? (car actions))
(cadr actions)
(car actions)))
(define reduce-prec (prod-prec (reduce-prod reduce)))
(cond
[(and shift-prec reduce-prec)
(cond
[(< (prec-num shift-prec) (prec-num reduce-prec))
(list reduce)]
[(> (prec-num shift-prec) (prec-num reduce-prec))
(list shift)]
[(eq? 'left (prec-assoc shift-prec))
(list reduce)]
[(eq? 'right (prec-assoc shift-prec))
(list shift)]
[else null])]
[else actions]))
;; resolve-prec-conflicts : parse-table -> grouped-parse-table
(define (resolve-prec-conflicts table)
(table-map
(λ (gs actions)
(cond
[(and (term? gs)
(= 2 (length actions))
(or (shift? (car actions))
(shift? (cadr actions))))
(resolve-sr-conflict/prec actions (term-prec gs))]
[else actions]))
(group-table table)))
;; build-table: grammar string bool -> parse-table
(define (build-table g file suppress)
(define a (build-lr0-automaton g))
(define term-vector (list->vector (send g get-terms)))
(define end-terms (send g get-end-terms))
(define table (make-parse-table (send a get-num-states)))
(define get-lookahead (compute-LA a g))
(define reduce-cache (make-hash))
(for ([trans-key/state (in-list (send a get-transitions))])
(define from-state-index (kernel-index (trans-key-st (car trans-key/state))))
(define gs (trans-key-gs (car trans-key/state)))
(define to-state (cdr trans-key/state))
(table-add! table from-state-index gs
(cond
((non-term? gs)
(make-goto (kernel-index to-state)))
((member gs end-terms)
(make-accept))
(else
(make-shift
(kernel-index to-state))))))
(send a for-each-state
(λ (state)
(for ([item (in-list (append (hash-ref (send a get-epsilon-trans) state (λ () null))
(filter (λ (item)
(not (move-dot-right item)))
(kernel-items state))))])
(let ([item-prod (item-prod item)])
(bit-vector-for-each
(λ (term-index)
(unless (start-item? item)
(let ((r (hash-ref reduce-cache item-prod
(λ ()
(let ((r (make-reduce item-prod)))
(hash-set! reduce-cache item-prod r)
r)))))
(table-add! table
(kernel-index state)
(vector-ref term-vector term-index)
r))))
(get-lookahead state item-prod))))))
(define grouped-table (resolve-prec-conflicts table))
(unless (string=? file "")
(with-handlers [(exn:fail:filesystem?
(λ (e)
(eprintf
"Cannot write debug output to file \"~a\": ~a\n"
file
(exn-message e))))]
(call-with-output-file file
(λ (port)
(display-parser a grouped-table (send g get-prods) port))
#:exists 'truncate)))
(resolve-conflicts grouped-table suppress))

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br-parser-tools-lib/br-parser-tools/private-yacc/yacc-helper.rkt
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#lang racket/base
(require (prefix-in rl: racket/list)
"../private-lex/token-syntax.rkt")
;; General helper routines
(provide duplicate-list? remove-duplicates overlap? vector-andmap display-yacc)
(define (vector-andmap pred vec)
(for/and ([item (in-vector vec)])
(pred vec)))
;; duplicate-list?: symbol list -> #f | symbol
;; returns a symbol that exists twice in l, or false if no such symbol
;; exists
(define (duplicate-list? syms)
(rl:check-duplicates syms eq?))
;; remove-duplicates: syntax-object list -> syntax-object list
;; removes the duplicates from the lists
(define (remove-duplicates syms)
(rl:remove-duplicates syms equal? #:key syntax->datum))
;; overlap?: symbol list * symbol list -> #f | symbol
;; Returns an symbol in l1 intersect l2, or #f is no such symbol exists
(define (overlap? syms1 syms2)
(for/first ([sym1 (in-list syms1)]
#:when (memq sym1 syms2))
sym1))
(define (display-yacc grammar tokens start precs port)
(let-syntax ([p (syntax-rules ()
((_ args ...) (fprintf port args ...)))])
(let* ([tokens (map syntax-local-value tokens)]
[eterms (filter e-terminals-def? tokens)]
[terms (filter terminals-def? tokens)]
[term-table (make-hasheq)]
[display-rhs
(λ (rhs)
(for ([sym (in-list (car rhs))])
(p "~a " (hash-ref term-table sym (λ () sym))))
(when (= 3 (length rhs))
(p "%prec ~a" (cadadr rhs)))
(p "\n"))])
(for* ([t (in-list eterms)]
[t (in-list (syntax->datum (e-terminals-def-t t)))])
(hash-set! term-table t (format "'~a'" t)))
(for* ([t (in-list terms)]
[t (in-list (syntax->datum (terminals-def-t t)))])
(p "%token ~a\n" t)
(hash-set! term-table t (format "~a" t)))
(when precs
(for ([prec (in-list precs)])
(p "%~a " (car prec))
(for ([tok (in-list (cdr prec))])
(p " ~a" (hash-ref term-table tok)))
(p "\n")))
(p "%start ~a\n" start)
(p "%%\n")
(for ([prod (in-list grammar)])
(define nt (car prod))
(p "~a: " nt)
(display-rhs (cadr prod))
(for ([rhs (in-list (cddr prod))])
(p "| ")
(display-rhs rhs))
(p ";\n"))
(p "%%\n"))))

130
br-parser-tools-lib/br-parser-tools/yacc-to-scheme.rkt
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#lang racket/base
(require br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre)
br-parser-tools/yacc
syntax/readerr
racket/list)
(provide trans)
(define match-double-string
(lexer
[(:+ (:~ #\" #\\)) (append (string->list lexeme)
(match-double-string input-port))]
[(:: #\\ any-char) (cons (string-ref lexeme 1) (match-double-string input-port))]
[#\" null]))
(define match-single-string
(lexer
[(:+ (:~ #\' #\\)) (append (string->list lexeme)
(match-single-string input-port))]
[(:: #\\ any-char) (cons (string-ref lexeme 1) (match-single-string input-port))]
[#\' null]))
(define-lex-abbrevs
[letter (:or (:/ "a" "z") (:/ "A" "Z"))]
[digit (:/ "0" "9")]
[initial (:or letter (char-set "!$%&*/<=>?^_~@"))]
[subsequent (:or initial digit (char-set "+-.@"))]
[comment (:: "/*" (complement (:: any-string "*/" any-string)) "*/")])
(define-empty-tokens x (EOF PIPE |:| SEMI |%%| %prec))
(define-tokens y (SYM STRING))
(define get-token-grammar
(lexer-src-pos
["%%" '|%%|]
[":" (string->symbol lexeme)]
["%prec" (string->symbol lexeme)]
[#\| 'PIPE]
[(:+ (:or #\newline #\tab " " comment (:: "{" (:* (:~ "}")) "}")))
(return-without-pos (get-token-grammar input-port))]
[#\; 'SEMI]
[#\' (token-STRING (string->symbol (list->string (match-single-string input-port))))]
[#\" (token-STRING (string->symbol (list->string (match-double-string input-port))))]
[(:: initial (:* subsequent)) (token-SYM (string->symbol lexeme))]))
(define (parse-grammar enter-term enter-empty-term enter-non-term)
(parser
(tokens x y)
(src-pos)
(error (λ (tok-ok tok-name tok-value start-pos end-pos)
(raise-read-error
(format "Error Parsing YACC grammar at token: ~a with value: ~a" tok-name tok-value)
(file-path)
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos) (position-offset start-pos)))))
(end |%%|)
(start gram)
(grammar
(gram
((production) (list $1))
((production gram) (cons $1 $2)))
(production
((SYM |:| prods SEMI)
(begin
(enter-non-term $1)
(cons $1 $3))))
(prods
((rhs) (list `(,$1 #f)))
((rhs prec) (list `(,$1 ,$2 #f)))
((rhs PIPE prods) (cons `(,$1 #f) $3))
((rhs prec PIPE prods) (cons `(,$1 ,$2 #f) $4)))
(prec
((%prec SYM)
(begin
(enter-term $2)
(list 'prec $2)))
((%prec STRING)
(begin
(enter-empty-term $2)
(list 'prec $2))))
(rhs
(() null)
((SYM rhs)
(begin
(enter-term $1)
(cons $1 $2)))
((STRING rhs)
(begin
(enter-empty-term $1)
(cons $1 $2)))))))
(define (symbol<? a b)
(string<? (symbol->string a) (symbol->string b)))
(define (trans filename)
(define i (open-input-file filename))
(define terms (make-hasheq))
(define eterms (make-hasheq))
(define nterms (make-hasheq))
(define (enter-term s)
(when (not (hash-ref nterms s (λ () #f)))
(hash-set! terms s #t)))
(define (enter-empty-term s)
(when (not (hash-ref nterms s (λ () #f)))
(hash-set! eterms s #t)))
(define (enter-non-term s)
(hash-remove! terms s)
(hash-remove! eterms s)
(hash-set! nterms s #t))
(port-count-lines! i)
(file-path filename)
(regexp-match "%%" i)
(begin0
(let ([gram ((parse-grammar enter-term enter-empty-term enter-non-term)
(λ ()
(let ((t (get-token-grammar i)))
t)))])
`(begin
(define-tokens t ,(sort (hash-map terms (λ (k v) k)) symbol<?))
(define-empty-tokens et ,(sort (hash-map eterms (λ (k v) k)) symbol<?))
(parser
(start ___)
(end ___)
(error ___)
(tokens t et)
(grammar ,@gram))))
(close-input-port i)))

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br-parser-tools-lib/br-parser-tools/yacc.rkt
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#lang racket/base
(require (for-syntax racket/base
"private-yacc/parser-builder.rkt"
"private-yacc/grammar.rkt"
"private-yacc/yacc-helper.rkt"
"private-yacc/parser-actions.rkt")
"private-lex/token.rkt"
"private-yacc/parser-actions.rkt"
racket/local
racket/pretty
syntax/readerr)
(provide parser)
;; convert-parse-table : (vectorof (listof (cons/c gram-sym? action?))) ->
;; (vectorof (symbol runtime-action hashtable))
(define-for-syntax (convert-parse-table table)
(for/vector ([state-entry (in-vector table)])
(let ([ht (make-hasheq)])
(for ([gs/action (in-list state-entry)])
(hash-set! ht
(gram-sym-symbol (car gs/action))
(action->runtime-action (cdr gs/action))))
ht)))
(define-syntax (parser stx)
(syntax-case stx ()
[(_ ARGS ...)
(let ([arg-list (syntax->list #'(ARGS ...))]
[src-pos #f]
[debug #f]
[error #f]
[tokens #f]
[start #f]
[end #f]
[precs #f]
[suppress #f]
[grammar #f]
[yacc-output #f])
(for ([arg (in-list (syntax->list #'(ARGS ...)))])
(syntax-case* arg (debug error tokens start end precs grammar
suppress src-pos yacc-output)
(λ (a b) (eq? (syntax-e a) (syntax-e b)))
[(debug FILENAME)
(cond
[(not (string? (syntax-e #'FILENAME)))
(raise-syntax-error #f "Debugging filename must be a string" stx #'FILENAME)]
[debug (raise-syntax-error #f "Multiple debug declarations" stx)]
[else (set! debug (syntax-e #'FILENAME))])]
[(suppress) (set! suppress #t)]
[(src-pos) (set! src-pos #t)]
[(error EXPRESSION)
(if error
(raise-syntax-error #f "Multiple error declarations" stx)
(set! error #'EXPRESSION))]
[(tokens DEF ...)
(begin
(when tokens
(raise-syntax-error #f "Multiple tokens declarations" stx))
(let ((defs (syntax->list #'(DEF ...))))
(for ([d (in-list defs)]
#:unless (identifier? d))
(raise-syntax-error #f "Token-group name must be an identifier" stx d))
(set! tokens defs)))]
[(start symbol ...)
(let ([symbols (syntax->list #'(symbol ...))])
(for ([sym (in-list symbols)]
#:unless (identifier? sym))
(raise-syntax-error #f "Start symbol must be a symbol" stx sym))
(when start
(raise-syntax-error #f "Multiple start declarations" stx))
(when (null? symbols)
(raise-syntax-error #f "Missing start symbol" stx arg))
(set! start symbols))]
[(end SYMBOLS ...)
(let ((symbols (syntax->list #'(SYMBOLS ...))))
(for ([sym (in-list symbols)]
#:unless (identifier? sym))
(raise-syntax-error #f "End token must be a symbol" stx sym))
(let ([d (duplicate-list? (map syntax-e symbols))])
(when d
(raise-syntax-error #f (format "Duplicate end token definition for ~a" d) stx arg))
(when (null? symbols)
(raise-syntax-error #f "end declaration must contain at least 1 token" stx arg))
(when end
(raise-syntax-error #f "Multiple end declarations" stx))
(set! end symbols)))]
[(precs DECLS ...)
(if precs
(raise-syntax-error #f "Multiple precs declarations" stx)
(set! precs (syntax/loc arg (DECLS ...))))]
[(grammar PRODS ...)
(if grammar
(raise-syntax-error #f "Multiple grammar declarations" stx)
(set! grammar (syntax/loc arg (PRODS ...))))]
[(yacc-output FILENAME)
(cond
[(not (string? (syntax-e #'FILENAME)))
(raise-syntax-error #f "Yacc-output filename must be a string" stx #'FILENAME)]
[yacc-output
(raise-syntax-error #f "Multiple yacc-output declarations" stx)]
[else
(set! yacc-output (syntax-e #'FILENAME))])]
[_ (raise-syntax-error #f "argument must match (debug filename), (error expression), (tokens def ...), (start non-term), (end tokens ...), (precs decls ...), or (grammar prods ...)" stx arg)]))
(unless tokens
(raise-syntax-error #f "missing tokens declaration" stx))
(unless error
(raise-syntax-error #f "missing error declaration" stx))
(unless grammar
(raise-syntax-error #f "missing grammar declaration" stx))
(unless end
(raise-syntax-error #f "missing end declaration" stx))
(unless start
(raise-syntax-error #f "missing start declaration" stx))
(let-values ([(table all-term-syms actions check-syntax-fix)
(build-parser (if debug debug "")
src-pos
suppress
tokens
start
end
precs
grammar)])
(when (and yacc-output (not (string=? yacc-output "")))
(with-handlers [(exn:fail:filesystem?
(λ (e) (eprintf "Cannot write yacc-output to file \"~a\"\n" yacc-output)))]
(call-with-output-file yacc-output
(λ (port)
(display-yacc (syntax->datum grammar)
tokens
(map syntax->datum start)
(and precs (syntax->datum precs))
port))
#:exists 'truncate)))
(with-syntax ([check-syntax-fix check-syntax-fix]
[err error]
[ends end]
[starts start]
[debug debug]
[table (convert-parse-table table)]
[all-term-syms all-term-syms]
[actions actions]
[src-pos src-pos])
#'(begin
check-syntax-fix
(parser-body debug err (quote starts) (quote ends) table all-term-syms actions src-pos)))))]
[_ (raise-syntax-error #f "parser must have the form (parser args ...)" stx)]))
(define (reduce-stack stack num ret-vals src-pos)
(cond
[(positive? num)
(define top-frame (car stack))
(let ([ret-vals (if src-pos
(cons (stack-frame-value top-frame)
(cons (stack-frame-start-pos top-frame)
(cons (stack-frame-end-pos top-frame)
ret-vals)))
(cons (stack-frame-value top-frame) ret-vals))])
(reduce-stack (cdr stack) (sub1 num) ret-vals src-pos))]
[else (values stack ret-vals)]))
;; extract-helper : (symbol or make-token) any any -> symbol any any any
(define (extract-helper tok v1 v2)
(cond
[(symbol? tok) (values tok #f v1 v2)]
[(token? tok) (values (real-token-name tok) (real-token-value tok) v1 v2)]
[else (raise-argument-error 'parser "(or/c symbol? token?)" 0 tok)]))
;; well-formed-position-token?: any -> boolean
;; Returns true if pt is a position token whose position-token-token
;; is itself a token or a symbol.
;; This is meant to help raise more precise error messages when
;; a tokenizer produces an erroneous position-token wrapped twice.
;; (as often happens when omitting return-without-pos).
(define (well-formed-token-field? t)
(or (symbol? t) (token? t)))
(define (well-formed-position-token? pt)
(and (position-token? pt)
(well-formed-token-field? (position-token-token pt))))
(define (well-formed-srcloc-token? st)
(and (srcloc-token? st)
(well-formed-token-field? (srcloc-token-token st))))
;; extract-src-pos : position-token -> symbol any any any
(define (extract-src-pos ip)
(unless (well-formed-position-token? ip)
(raise-argument-error 'parser "well-formed-position-token?" 0 ip))
(extract-helper (position-token-token ip)
(position-token-start-pos ip)
(position-token-end-pos ip)))
(define (extract-srcloc ip)
(unless (well-formed-srcloc-token? ip)
(raise-argument-error 'parser "well-formed-srcloc-token?" 0 ip))
(define loc (srcloc-token-srcloc ip))
(extract-helper (srcloc-token-token ip)
(position-token (srcloc-position loc) (srcloc-line loc) (srcloc-column loc))
(position-token (+ (srcloc-position loc) (srcloc-span loc)) #f #f)))
;; extract-no-src-pos : (symbol or make-token) -> symbol any any any
(define (extract-no-src-pos ip)
(extract-helper ip #f #f))
(define-struct stack-frame (state value start-pos end-pos) #:inspector (make-inspector))
(define (make-empty-stack i) (list (make-stack-frame i #f #f #f)))
;; The table is a vector that maps each state to a hash-table that maps a
;; terminal symbol to either an accept, shift, reduce, or goto structure.
; We encode the structures according to the runtime-action data definition in
;; parser-actions.rkt
(define (parser-body debug? err starts ends table all-term-syms actions src-pos)
(local ((define extract
(if src-pos
extract-src-pos
extract-no-src-pos))
(define (fix-error stack tok val start-pos end-pos get-token)
(when debug? (pretty-print stack))
(local ((define (remove-input tok val start-pos end-pos)
(if (memq tok ends)
(raise-read-error "parser: Cannot continue after error"
#f #f #f #f #f)
(let ([a (find-action stack tok val start-pos end-pos)])
(cond
[(runtime-shift? a)
;; (printf "shift:~a\n" (runtime-shift-state a))
(cons (make-stack-frame (runtime-shift-state a)
val
start-pos
end-pos)
stack)]
[else
;; (printf "discard input:~a\n" tok)
(let-values ([(tok val start-pos end-pos)
(extract (get-token))])
(remove-input tok val start-pos end-pos))])))))
(let remove-states ()
(let ([a (find-action stack 'error #f start-pos end-pos)])
(cond
[(runtime-shift? a)
;; (printf "shift:~a\n" (runtime-shift-state a))
(set! stack
(cons
(make-stack-frame (runtime-shift-state a)
#f
start-pos
end-pos)
stack))
(remove-input tok val start-pos end-pos)]
[else
;; (printf "discard state:~a\n" (car stack))
(cond
[(< (length stack) 2)
(raise-read-error "parser: Cannot continue after error"
#f #f #f #f #f)]
[else
(set! stack (cdr stack))
(remove-states)])])))))
(define (find-action stack tok val start-pos end-pos)
(unless (hash-ref all-term-syms tok #f)
(if src-pos
(err #f tok val start-pos end-pos)
(err #f tok val))
(raise-read-error (format "parser: got token of unknown type ~a" tok)
#f #f #f #f #f))
(hash-ref (vector-ref table (stack-frame-state (car stack))) tok #f))
(define ((make-parser start-number) get-token)
(unless (and (procedure? get-token)
(procedure-arity-includes? get-token 0))
(error 'get-token "expected a nullary procedure, got ~e" get-token))
(let parsing-loop ([stack (make-empty-stack start-number)]
[ip (get-token)])
(let-values ([(tok val start-pos end-pos) (extract ip)])
(let ([action (find-action stack tok val start-pos end-pos)])
(cond
[(runtime-shift? action)
;; (printf "shift:~a\n" (runtime-shift-state action))
(parsing-loop (cons (make-stack-frame (runtime-shift-state action)
val
start-pos
end-pos)
stack)
(get-token))]
[(runtime-reduce? action)
;; (printf "reduce:~a\n" (runtime-reduce-prod-num action))
(let-values ([(new-stack args)
(reduce-stack stack
(runtime-reduce-rhs-length action)
null
src-pos)])
(let ([goto
(runtime-goto-state
(hash-ref
(vector-ref table (stack-frame-state (car new-stack)))
(runtime-reduce-lhs action)))])
(parsing-loop
(cons
(if src-pos
(make-stack-frame
goto
(apply (vector-ref actions (runtime-reduce-prod-num action)) args)
(if (null? args) start-pos (cadr args))
(if (null? args)
end-pos
(list-ref args (- (* (runtime-reduce-rhs-length action) 3) 1))))
(make-stack-frame
goto
(apply (vector-ref actions (runtime-reduce-prod-num action)) args)
#f
#f))
new-stack)
ip)))]
[(runtime-accept? action)
;; (printf "accept\n")
(stack-frame-value (car stack))]
[else
(if src-pos
(err #t tok val start-pos end-pos)
(err #t tok val))
(parsing-loop (fix-error stack tok val start-pos end-pos get-token)
(get-token))]))))))
(cond
[(null? (cdr starts)) (make-parser 0)]
[else
(for/list ([(l i) (in-indexed starts)])
(make-parser i))])))

12
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@ -1,12 +0,0 @@
#lang info
(define collection 'multi)
(define deps '("br-parser-tools-lib"
"br-parser-tools-doc"))
(define implies '("br-parser-tools-lib"
"br-parser-tools-doc"))
(define pkg-desc "Lex- and Yacc-style parsing tools")
(define pkg-authors '(mflatt))

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@ -5,10 +5,10 @@
(define build-deps '("scheme-lib"
"racket-doc"
"syntax-color-doc"
"br-parser-tools-lib"
"parser-tools-lib"
"scribble-lib"))
(define update-implies '("br-parser-tools-lib"))
(define update-implies '("parser-tools-lib"))
(define pkg-desc "documentation part of \"br-parser-tools\"")
(define pkg-desc "documentation part of \"parser-tools\"")
(define pkg-authors '(mflatt))

3
parser-tools-doc/parser-tools/info.rkt
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@ -0,0 +1,3 @@
#lang info
(define scribblings '(("parser-tools.scrbl" (multi-page) (parsing-library))))

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@ -2,19 +2,17 @@
@(require scribble/manual scribble/struct scribble/xref scribble/bnf
(for-label scheme/base
scheme/contract
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre)
br-parser-tools/yacc
br-parser-tools/cfg-parser))
parser-tools/lex
(prefix-in : parser-tools/lex-sre)
parser-tools/yacc
parser-tools/cfg-parser))
@title{Parser Tools: @exec{lex} and @exec{yacc}-style Parsing (BR edition)}
@title{Parser Tools: @exec{lex} and @exec{yacc}-style Parsing}
@author["Scott Owens (99%)" "Matthew Butterick (1%)"]
This documentation assumes familiarity with @exec{lex}- and @exec{yacc}-style lexer and parser generators.
@margin-note{This is a fork of the @link["https://docs.racket-lang.org/parser-tools"]{@racket[parser-tools]} package. It has a variety of small improvements and bugfixes designed to support the @link["https://docs.racket-lang.org/brag"]{@racket[brag]} parser language, in particular the @racket[srcloc] structure type (e.g., @racket[lexer-srcloc]). But the core lexing and parsing engines are identical.}
@author["Scott Owens"]
This documentation assumes familiarity with @exec{lex} and @exec{yacc}
style lexer and parser generators.
@table-of-contents[]
@ -26,7 +24,7 @@ This documentation assumes familiarity with @exec{lex}- and @exec{yacc}-style le
@section-index["scanning"]
@section-index["scanner"]
@defmodule[br-parser-tools/lex]
@defmodule[parser-tools/lex]
@; ----------------------------------------
@ -61,7 +59,7 @@ This documentation assumes familiarity with @exec{lex}- and @exec{yacc}-style le
@margin-note{The implementation of @racketmodname[syntax-color/racket-lexer]
contains a lexer for the @racketmodname[racket] language.
In addition, files in the @filepath{examples} sub-directory
of the @filepath{br-parser-tools} collection contain
of the @filepath{parser-tools} collection contain
simpler example lexers.}
An @racket[re] is matched as follows:
@ -69,7 +67,7 @@ This documentation assumes familiarity with @exec{lex}- and @exec{yacc}-style le
@itemize[
@item{@racket[id] --- expands to the named @deftech{lexer abbreviation};
abbreviations are defined via @racket[define-lex-abbrev] or supplied by modules
like @racketmodname[br-parser-tools/lex-sre].}
like @racketmodname[parser-tools/lex-sre].}
@item{@racket[string] --- matches the sequence of characters in @racket[string].}
@item{@racket[character] --- matches a literal @racket[character].}
@item{@racket[(repetition lo hi re)] --- matches @racket[re] repeated between @racket[lo]
@ -94,15 +92,15 @@ empty string, @racket[(union)] matches nothing,
The regular expression language is not designed to be used directly,
but rather as a basis for a user-friendly notation written with
regular expression macros. For example,
@racketmodname[br-parser-tools/lex-sre] supplies operators from Olin
Shivers's SREs, and @racketmodname[br-parser-tools/lex-plt-v200] supplies
@racketmodname[parser-tools/lex-sre] supplies operators from Olin
Shivers's SREs, and @racketmodname[parser-tools/lex-plt-v200] supplies
(deprecated) operators from the previous version of this library.
Since those libraries provide operators whose names match other Racket
bindings, such as @racket[*] and @racket[+], they normally must be
imported using a prefix:
@racketblock[
(require (prefix-in : br-parser-tools/lex-sre))
(require (prefix-in : parser-tools/lex-sre))
]
The suggested prefix is @racket[:], so that @racket[:*] and
@ -169,14 +167,14 @@ are a few examples, using @racket[:] prefixed SRE syntax:
@item{@racket[input-port] --- the input-port being
processed (this is useful for matching input with multiple
lexers).}
@item{@racket[(return-without-pos x)] and @racket[(return-without-srcloc x)] are functions (continuations) that
immediately return the value of @racket[x] from the lexer. This useful
in a src-pos or src-loc lexer to prevent the lexer from adding source
@item{@racket[(return-without-pos x)] is a function (continuation) that
immediately returns the value of @racket[x] from the lexer. This useful
in a src-pos lexer to prevent the lexer from adding source
information. For example:
@racketblock[
(define get-token
(lexer-srcloc
(lexer-src-pos
...
((comment) (get-token input-port))
...))
@ -184,12 +182,12 @@ are a few examples, using @racket[:] prefixed SRE syntax:
would wrap the source location information for the comment around
the value of the recursive call. Using
@racket[((comment) (return-without-srcloc (get-token input-port)))]
@racket[((comment) (return-without-pos (get-token input-port)))]
will cause the value of the recursive call to be returned without
wrapping position around it.}
]
The lexer raises an @racket[exn:fail:read] exception if none of the
The lexer raises an exception @racket[(exn:read)] if none of the
regular expressions match the input. Hint: If @racket[(any-char
_custom-error-behavior)] is the last rule, then there will always
be a match, and @racket[_custom-error-behavior] is executed to
@ -250,21 +248,12 @@ an @racket[action-expr], returns @racket[(make-position-token
_action-result start-pos end-pos)] instead of simply
@racket[_action-result].}
@defform[(lexer-srcloc (trigger action-expr) ...)]{
Like @racket[lexer], but for each @racket[_action-result] produced by
an @racket[action-expr], returns @racket[(make-srcloc-token
_action-result lexeme-srcloc)] instead of simply
@racket[_action-result].}
@deftogether[(
@defidform[start-pos]
@defidform[end-pos]
@defidform[lexeme]
@defidform[lexeme-srcloc]
@defidform[input-port]
@defidform[return-without-pos]
@defidform[return-without-srcloc]
)]{
Use of these names outside of a @racket[lexer] action is a syntax
@ -287,21 +276,12 @@ error.}
Lexers created with @racket[lexer-src-pos] return instances of @racket[position-token].}
@defstruct[srcloc-token ([token any/c]
[srcloc srcloc?])]{
Lexers created with @racket[lexer-srcloc] return instances of @racket[srcloc-token].}
@defparam[file-path source any/c]{
A parameter that the lexer uses as the source location if it
raises a @racket[exn:fail:read] error. Setting this parameter allows
DrRacket, for example, to open the file containing the error.}
@defparam[lexer-file-path source any/c]{
Alias for @racket[file-path].}
@; ----------------------------------------
@ -360,41 +340,41 @@ characters, @racket[char-lower-case?] characters, etc.}
@subsection{Lexer SRE Operators}
@defmodule[br-parser-tools/lex-sre]
@defmodule[parser-tools/lex-sre]
@; Put the docs in a macro, so that we can bound the scope of
@; the import of `*', etc.:
@(define-syntax-rule (lex-sre-doc)
(...
(begin
(require (for-label br-parser-tools/lex-sre))
(require (for-label parser-tools/lex-sre))
@defform[(* re ...)]{
0 or more occurrences of any @racket[re] pattern.}
Repetition of @racket[re] sequence 0 or more times.}
@defform[(+ re ...)]{
1 or more occurrences of any @racket[re] pattern.}
Repetition of @racket[re] sequence 1 or more times.}
@defform[(? re ...)]{
0 or 1 occurrence of any @racket[re] pattern.}
Zero or one occurrence of @racket[re] sequence.}
@defform[(= n re ...)]{
Exactly @racket[n] occurrences of any @racket[re] pattern, where
Exactly @racket[n] occurrences of @racket[re] sequence, where
@racket[n] must be a literal exact, non-negative number.}
@defform[(>= n re ...)]{
At least @racket[n] occurrences of any @racket[re] pattern, where
At least @racket[n] occurrences of @racket[re] sequence, where
@racket[n] must be a literal exact, non-negative number.}
@defform[(** n m re ...)]{
Between @racket[n] and @racket[m] (inclusive) occurrences of
any @racket[re] pattern, where @racket[n] must be a literal exact,
@racket[re] sequence, where @racket[n] must be a literal exact,
non-negative number, and @racket[m] must be literally either
@racket[#f], @racket[+inf.0], or an exact, non-negative number; a
@racket[#f] value for @racket[m] is the same as @racket[+inf.0].}
@ -408,8 +388,7 @@ Same as @racket[(union re ...)].}
@defform[(seq re ...)]
)]{
Both forms concatenate the @racket[re]s into a single, indivisible pattern.
In other words, this matches @emph{all} the @racket[re]s in order, whereas @racket[(union re ...)] matches @emph{any} of the @racket[re]s.}
Both forms concatenate the @racket[re]s.}
@defform[(& re ...)]{
@ -437,16 +416,16 @@ characters.}
@subsection{Lexer Legacy Operators}
@defmodule[br-parser-tools/lex-plt-v200]
@defmodule[parser-tools/lex-plt-v200]
@(define-syntax-rule (lex-v200-doc)
(...
(begin
(require (for-label br-parser-tools/lex-plt-v200))
(require (for-label parser-tools/lex-plt-v200))
@t{The @racketmodname[br-parser-tools/lex-plt-v200] module re-exports
@t{The @racketmodname[parser-tools/lex-plt-v200] module re-exports
@racket[*], @racket[+], @racket[?], and @racket[&] from
@racketmodname[br-parser-tools/lex-sre]. It also re-exports
@racketmodname[parser-tools/lex-sre]. It also re-exports
@racket[:or] as @racket[:], @racket[::] as @racket[|@|], @racket[:~]
as @racket[^], and @racket[:/] as @racket[-].}
@ -467,7 +446,7 @@ The same as @racket[(complement re ...)].})))
Each @racket[_action-expr] in a @racket[lexer] form can produce any
kind of value, but for many purposes, producing a @deftech{token}
value is useful. Tokens are usually necessary for inter-operating with
a parser generated by @racket[br-parser-tools/parser], but tokens may not
a parser generated by @racket[parser-tools/parser], but tokens may not
be the right choice when using @racket[lexer] in other situations.
@defform[(define-tokens group-id (token-id ...))]{
@ -513,7 +492,7 @@ be the right choice when using @racket[lexer] in other situations.
@section-index["yacc"]
@defmodule[br-parser-tools/yacc]
@defmodule[parser-tools/yacc]
@defform/subs[#:literals (grammar tokens start end precs src-pos
suppress debug yacc-output prec)
@ -712,9 +691,9 @@ be the right choice when using @racket[lexer] in other situations.
@section-index["cfg-parser"]
@defmodule[br-parser-tools/cfg-parser]{The @racketmodname[br-parser-tools/cfg-parser]
@defmodule[parser-tools/cfg-parser]{The @racketmodname[parser-tools/cfg-parser]
library provides a parser generator that is an alternative to that of
@racketmodname[br-parser-tools/yacc].}
@racketmodname[parser-tools/yacc].}
@defform/subs[#:literals (grammar tokens start end precs src-pos
suppress debug yacc-output prec)
@ -731,7 +710,7 @@ library provides a parser generator that is an alternative to that of
Creates a parser similar to that of @racket[parser]. Unlike @racket[parser],
@racket[cfg-parser], can consume arbitrary and potentially ambiguous context-free
grammars. Its interface is a subset of @racketmodname[br-parser-tools/yacc], with
grammars. Its interface is a subset of @racketmodname[parser-tools/yacc], with
the following differences:
@itemize[
@ -751,7 +730,7 @@ library provides a parser generator that is an alternative to that of
@section{Converting @exec{yacc} or @exec{bison} Grammars}
@defmodule[br-parser-tools/yacc-to-scheme]
@defmodule[parser-tools/yacc-to-scheme]
@defproc[(trans [file path-string?]) any/c]{
@ -765,7 +744,7 @@ conversion tool. It is not entirely robust. For example, if the C
actions in the original grammar have nested blocks, the tool will fail.
Annotated examples are in the @filepath{examples} subdirectory of the
@filepath{br-parser-tools} collection.}
@filepath{parser-tools} collection.}
@; ----------------------------------------------------------------------

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@ -6,4 +6,6 @@
"compatibility-lib"))
(define build-deps '("rackunit-lib"))
(define pkg-desc "implementation (no documentation) part of \"br-parser-tools\"")
(define pkg-desc "implementation (no documentation) part of \"parser-tools\"")
(define pkg-authors '(mflatt))

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@ -1,5 +1,5 @@
#lang racket/base
;; This module implements a parser form like the br-parser-tools's
;; This module implements a parser form like the parser-tools's
;; `parser', except that it works on an arbitrary CFG (returning
;; the first sucecssful parse).
@ -23,7 +23,7 @@
;; different lengths. (Otherwise, in the spirit of finding one
;; successful parse, only the first result is kept.)
;; The br-parser-tools's `parse' is used to transform tokens in the
;; The parser-tools's `parse' is used to transform tokens in the
;; grammar to tokens specific to this parser. In other words, this
;; parser uses `parser' so that it doesn't have to know anything about
;; tokens.
@ -31,12 +31,12 @@
(require br-parser-tools/yacc
br-parser-tools/lex)
(require parser-tools/yacc
parser-tools/lex)
(require (for-syntax racket/base
syntax/boundmap
br-parser-tools/private-lex/token-syntax))
parser-tools/private-lex/token-syntax))
(provide cfg-parser)
@ -47,16 +47,18 @@
(define-struct tasks (active active-back waits multi-waits cache progress?))
(define-for-syntax make-token-identifier-mapping make-hasheq)
(define-for-syntax (token-identifier-mapping-get t tok [fail #f])
(if fail
(hash-ref t (syntax-e tok) fail)
(hash-ref t (syntax-e tok))))
(define-for-syntax (token-identifier-mapping-put! t tok v)
(hash-set! t (syntax-e tok) v))
(define-for-syntax (token-identifier-mapping-map t f)
(hash-map t f))
(define-for-syntax token-identifier-mapping-get
(case-lambda
[(t tok)
(hash-ref t (syntax-e tok))]
[(t tok fail)
(hash-ref t (syntax-e tok) fail)]))
(define-for-syntax token-identifier-mapping-put!
(lambda (t tok v)
(hash-set! t (syntax-e tok) v)))
(define-for-syntax token-identifier-mapping-map
(lambda (t f)
(hash-map t f)))
;; Used to calculate information on the grammar, such as whether
;; a particular non-terminal is "simple" instead of recursively defined.
@ -69,7 +71,7 @@
(cdr as) (cdr bs))]))
(let loop ()
(when (ormap-all #f
(λ (nt pats)
(lambda (nt pats)
(let ([old (bound-identifier-mapping-get nts nt)])
(let ([new (proc nt pats old)])
(if (equal? old new)
@ -86,120 +88,149 @@
(define (parse-and simple-a? parse-a parse-b
stream last-consumed-token depth end success-k fail-k
max-depth tasks)
(define ((mk-got-k success-k fail-k) val stream last-consumed-token depth max-depth tasks next1-k)
(letrec ([mk-got-k
(lambda (success-k fail-k)
(lambda (val stream last-consumed-token depth max-depth tasks next1-k)
(if simple-a?
(parse-b val stream last-consumed-token depth end
(mk-got2-k success-k fail-k next1-k)
(mk-fail2-k success-k fail-k next1-k)
max-depth tasks)
(parallel-or
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(parse-b val stream last-consumed-token depth end
success-k fail-k
max-depth tasks))
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(next1-k (mk-got-k success-k fail-k)
fail-k max-depth tasks))
success-k fail-k max-depth tasks)))
(define ((mk-got2-k success-k fail-k next1-k) val stream last-consumed-token depth max-depth tasks next-k)
success-k fail-k max-depth tasks))))]
[mk-got2-k
(lambda (success-k fail-k next1-k)
(lambda (val stream last-consumed-token depth max-depth tasks next-k)
(success-k val stream last-consumed-token depth max-depth tasks
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(next-k (mk-got2-k success-k fail-k next1-k)
(mk-fail2-k success-k fail-k next1-k)
max-depth tasks))))
(define ((mk-fail2-k success-k fail-k next1-k) max-depth tasks)
(next1-k (mk-got-k success-k fail-k) fail-k max-depth tasks))
max-depth tasks)))))]
[mk-fail2-k
(lambda (success-k fail-k next1-k)
(lambda (max-depth tasks)
(next1-k (mk-got-k success-k fail-k)
fail-k
max-depth
tasks)))])
(parse-a stream last-consumed-token depth end
(mk-got-k success-k fail-k)
fail-k
max-depth tasks))
max-depth tasks)))
;; Parallel or for non-terminal alternatives
(define (parse-parallel-or parse-a parse-b stream last-consumed-token depth end success-k fail-k max-depth tasks)
(parallel-or (λ (success-k fail-k max-depth tasks)
(parallel-or (lambda (success-k fail-k max-depth tasks)
(parse-a stream last-consumed-token depth end success-k fail-k max-depth tasks))
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(parse-b stream last-consumed-token depth end success-k fail-k max-depth tasks))
success-k fail-k max-depth tasks))
;; Generic parallel-or
(define (parallel-or parse-a parse-b success-k fail-k max-depth tasks)
(define answer-key (gensym))
(define (gota-k val stream last-consumed-token depth max-depth tasks next-k)
(letrec ([gota-k
(lambda (val stream last-consumed-token depth max-depth tasks next-k)
(report-answer answer-key
max-depth
tasks
(list val stream last-consumed-token depth next-k)))
(define (faila-k max-depth tasks)
(list val stream last-consumed-token depth next-k)))]
[faila-k
(lambda (max-depth tasks)
(report-answer answer-key
max-depth
tasks
null))
(let* ([tasks (queue-task tasks (λ (max-depth tasks)
(parse-a gota-k faila-k max-depth tasks)))]
[tasks (queue-task tasks (λ (max-depth tasks)
(parse-b gota-k faila-k max-depth tasks)))]
[queue-next (λ (next-k tasks)
(queue-task tasks (λ (max-depth tasks)
(next-k gota-k faila-k max-depth tasks))))])
(define ((mk-got-one immediate-next? get-nth success-k) val stream last-consumed-token depth max-depth tasks next-k)
null))])
(let* ([tasks (queue-task
tasks
(lambda (max-depth tasks)
(parse-a gota-k
faila-k
max-depth tasks)))]
[tasks (queue-task
tasks
(lambda (max-depth tasks)
(parse-b gota-k
faila-k
max-depth tasks)))]
[queue-next (lambda (next-k tasks)
(queue-task tasks
(lambda (max-depth tasks)
(next-k gota-k
faila-k
max-depth tasks))))])
(letrec ([mk-got-one
(lambda (immediate-next? get-nth success-k)
(lambda (val stream last-consumed-token depth max-depth tasks next-k)
(let ([tasks (if immediate-next?
(queue-next next-k tasks)
tasks)])
(success-k val stream last-consumed-token depth max-depth
tasks
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(let ([tasks (if immediate-next?
tasks
(queue-next next-k tasks))])
(get-nth max-depth tasks success-k fail-k))))))
(define (get-first max-depth tasks success-k fail-k)
(get-nth max-depth tasks success-k fail-k)))))))]
[get-first
(lambda (max-depth tasks success-k fail-k)
(wait-for-answer #f max-depth tasks answer-key
(mk-got-one #t get-first success-k)
(λ (max-depth tasks)
(lambda (max-depth tasks)
(get-second max-depth tasks success-k fail-k))
#f))
(define (get-second max-depth tasks success-k fail-k)
#f))]
[get-second
(lambda (max-depth tasks success-k fail-k)
(wait-for-answer #f max-depth tasks answer-key
(mk-got-one #f get-second success-k)
fail-k #f))
(get-first max-depth tasks success-k fail-k)))
fail-k #f))])
(get-first max-depth tasks success-k fail-k)))))
;; Non-terminal alternatives where the first is "simple" can be done
;; sequentially, which is simpler
(define (parse-or parse-a parse-b
stream last-consumed-token depth end success-k fail-k max-depth tasks)
(define ((mk-got-k success-k fail-k) val stream last-consumed-token depth max-depth tasks next-k)
(letrec ([mk-got-k
(lambda (success-k fail-k)
(lambda (val stream last-consumed-token depth max-depth tasks next-k)
(success-k val stream last-consumed-token depth
max-depth tasks
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(next-k (mk-got-k success-k fail-k)
(mk-fail-k success-k fail-k)
max-depth tasks))))
(define ((mk-fail-k success-k fail-k) max-depth tasks)
(parse-b stream last-consumed-token depth end success-k fail-k max-depth tasks))
max-depth tasks)))))]
[mk-fail-k
(lambda (success-k fail-k)
(lambda (max-depth tasks)
(parse-b stream last-consumed-token depth end success-k fail-k max-depth tasks)))])
(parse-a stream last-consumed-token depth end
(mk-got-k success-k fail-k)
(mk-fail-k success-k fail-k)
max-depth tasks))
max-depth tasks)))
;; Starts a thread
(define (queue-task tasks t [progress? #t])
(define queue-task
(lambda (tasks t [progress? #t])
(make-tasks (tasks-active tasks)
(cons t (tasks-active-back tasks))
(tasks-waits tasks)
(tasks-multi-waits tasks)
(tasks-cache tasks)
(or progress? (tasks-progress? tasks))))
(or progress? (tasks-progress? tasks)))))
;; Reports an answer to a waiting thread:
(define (report-answer answer-key max-depth tasks val)
(define v (hash-ref (tasks-waits tasks) answer-key (λ () #f)))
(let ([v (hash-ref (tasks-waits tasks) answer-key (lambda () #f))])
(if v
(let ([tasks (make-tasks (cons (v val) (tasks-active tasks))
(let ([tasks (make-tasks (cons (v val)
(tasks-active tasks))
(tasks-active-back tasks)
(tasks-waits tasks)
(tasks-multi-waits tasks)
@ -210,29 +241,29 @@
;; We have an answer ready too fast; wait
(swap-task max-depth
(queue-task tasks
(λ (max-depth tasks)
(lambda (max-depth tasks)
(report-answer answer-key max-depth tasks val))
#f))))
#f)))))
;; Reports an answer to multiple waiting threads:
(define (report-answer-all answer-key max-depth tasks val k)
(define v (hash-ref (tasks-multi-waits tasks) answer-key (λ () null)))
(let ([v (hash-ref (tasks-multi-waits tasks) answer-key (lambda () null))])
(hash-remove! (tasks-multi-waits tasks) answer-key)
(let ([tasks (make-tasks (append (map (λ (a) (a val)) v)
(let ([tasks (make-tasks (append (map (lambda (a) (a val)) v)
(tasks-active tasks))
(tasks-active-back tasks)
(tasks-waits tasks)
(tasks-multi-waits tasks)
(tasks-cache tasks)
#t)])
(k max-depth tasks)))
(k max-depth tasks))))
;; Waits for an answer; if `multi?' is #f, this is sole waiter, otherwise
;; there might be many. Use wither #t or #f (and `report-answer' or
;; `report-answer-all', resptively) consistently for a particular answer key.
(define (wait-for-answer multi? max-depth tasks answer-key success-k fail-k deadlock-k)
(let ([wait (λ (val)
(λ (max-depth tasks)
(let ([wait (lambda (val)
(lambda (max-depth tasks)
(if val
(if (null? val)
(fail-k max-depth tasks)
@ -242,7 +273,7 @@
(if multi?
(hash-set! (tasks-multi-waits tasks) answer-key
(cons wait (hash-ref (tasks-multi-waits tasks) answer-key
(λ () null))))
(lambda () null))))
(hash-set! (tasks-waits tasks) answer-key wait))
(let ([tasks (make-tasks (tasks-active tasks)
(tasks-active-back tasks)
@ -271,8 +302,8 @@
(make-tasks (apply
append
(hash-map (tasks-multi-waits tasks)
(λ (k l)
(map (λ (v) (v #f)) l))))
(lambda (k l)
(map (lambda (v) (v #f)) l))))
(tasks-active-back tasks)
(tasks-waits tasks)
(make-hasheq)
@ -294,9 +325,11 @@
(define no-pos-val (make-position #f #f #f))
(define-for-syntax no-pos
(let ([npv ((syntax-local-certifier) #'no-pos-val)])
(λ (stx) npv)))
(define-for-syntax ((at-tok-pos sel expr) stx)
#`(let ([v #,expr]) (if v (#,sel v) no-pos-val)))
(lambda (stx) npv)))
(define-for-syntax at-tok-pos
(lambda (sel expr)
(lambda (stx)
#`(let ([v #,expr]) (if v (#,sel v) no-pos-val)))))
;; Builds a matcher for a particular alternative
(define-for-syntax (build-match nts toks pat handle $ctx)
@ -304,23 +337,27 @@
[pos 1])
(if (null? pat)
#`(success-k #,handle stream last-consumed-token depth max-depth tasks
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(fail-k max-depth tasks)))
(let ([id (datum->syntax (car pat) (string->symbol (format "$~a" pos)))]
[id-start-pos (datum->syntax (car pat) (string->symbol (format "$~a-start-pos" pos)))]
[id-end-pos (datum->syntax (car pat) (string->symbol (format "$~a-end-pos" pos)))]
[n-end-pos (and (null? (cdr pat)) (datum->syntax (car pat) '$n-end-pos))])
(let ([id (datum->syntax (car pat)
(string->symbol (format "$~a" pos)))]
[id-start-pos (datum->syntax (car pat)
(string->symbol (format "$~a-start-pos" pos)))]
[id-end-pos (datum->syntax (car pat)
(string->symbol (format "$~a-end-pos" pos)))]
[n-end-pos (and (null? (cdr pat))
(datum->syntax (car pat) '$n-end-pos))])
(cond
[(bound-identifier-mapping-get nts (car pat) (λ () #f))
[(bound-identifier-mapping-get nts (car pat) (lambda () #f))
;; Match non-termimal
#`(parse-and
;; First part is simple? (If so, we don't have to parallelize the `and'.)
#,(let ([l (bound-identifier-mapping-get nts (car pat) (λ () #f))])
#,(let ([l (bound-identifier-mapping-get nts (car pat) (lambda () #f))])
(or (not l)
(andmap values (caddr l))))
#,(car pat)
(let ([original-stream stream])
(λ (#,id stream last-consumed-token depth end success-k fail-k max-depth tasks)
(lambda (#,id stream last-consumed-token depth end success-k fail-k max-depth tasks)
(let-syntax ([#,id-start-pos (at-tok-pos #'(if (eq? original-stream stream)
tok-end
tok-start)
@ -335,10 +372,10 @@
#,(loop (cdr pat) (add1 pos)))))
stream last-consumed-token depth
#,(let ([cnt (apply +
(map (λ (item)
(map (lambda (item)
(cond
[(bound-identifier-mapping-get nts item (λ () #f))
=> (λ (l) (car l))]
[(bound-identifier-mapping-get nts item (lambda () #f))
=> (lambda (l) (car l))]
[else 1]))
(cdr pat)))])
#`(- end #,cnt))
@ -382,36 +419,37 @@
[max-depth max-depth]
[tasks tasks]
[k k])
(define answer-key (gensym))
(define table-key (vector key depth n))
(define old-depth depth)
(define old-stream stream)
(let ([answer-key (gensym)]
[table-key (vector key depth n)]
[old-depth depth]
[old-stream stream])
#;(printf "Loop ~a\n" table-key)
(cond
[(hash-ref (tasks-cache tasks) table-key (λ () #f))
=> (λ (result)
[(hash-ref (tasks-cache tasks) table-key (lambda () #f))
=> (lambda (result)
#;(printf "Reuse ~a\n" table-key)
(result success-k fail-k max-depth tasks))]
[else
#;(printf "Try ~a ~a\n" table-key (map tok-name stream))
(hash-set! (tasks-cache tasks) table-key
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
#;(printf "Wait ~a ~a\n" table-key answer-key)
(wait-for-answer #t max-depth tasks answer-key success-k fail-k
(λ (max-depth tasks)
(lambda (max-depth tasks)
#;(printf "Deadlock ~a ~a\n" table-key answer-key)
(fail-k max-depth tasks)))))
(let result-loop ([max-depth max-depth][tasks tasks][k k])
(define orig-stream stream)
(define (new-got-k val stream last-consumed-token depth max-depth tasks next-k)
(letrec ([orig-stream stream]
[new-got-k
(lambda (val stream last-consumed-token depth max-depth tasks next-k)
;; Check whether we already have a result that consumed the same amount:
(define result-key (vector #f key old-depth depth))
(let ([result-key (vector #f key old-depth depth)])
(cond
[(hash-ref (tasks-cache tasks) result-key (λ () #f))
[(hash-ref (tasks-cache tasks) result-key (lambda () #f))
;; Go for the next-result
(result-loop max-depth
tasks
(λ (end max-depth tasks success-k fail-k)
(lambda (end max-depth tasks success-k fail-k)
(next-k success-k fail-k max-depth tasks)))]
[else
#;(printf "Success ~a ~a\n" table-key
@ -419,36 +457,37 @@
(if (= d depth)
null
(cons (car s) (loop (add1 d) (cdr s)))))))
(let ([next-k (λ (success-k fail-k max-depth tasks)
(let ([next-k (lambda (success-k fail-k max-depth tasks)
(loop (add1 n)
success-k
fail-k
max-depth
tasks
(λ (end max-depth tasks success-k fail-k)
(lambda (end max-depth tasks success-k fail-k)
(next-k success-k fail-k max-depth tasks))))])
(hash-set! (tasks-cache tasks) result-key #t)
(hash-set! (tasks-cache tasks) table-key
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(success-k val stream last-consumed-token depth max-depth tasks next-k)))
(report-answer-all answer-key
max-depth
tasks
(list val stream last-consumed-token depth next-k)
(λ (max-depth tasks)
(success-k val stream last-consumed-token depth max-depth tasks next-k))))]))
(define (new-fail-k max-depth tasks)
(lambda (max-depth tasks)
(success-k val stream last-consumed-token depth max-depth tasks next-k))))])))]
[new-fail-k
(lambda (max-depth tasks)
#;(printf "Failure ~a\n" table-key)
(hash-set! (tasks-cache tasks) table-key
(λ (success-k fail-k max-depth tasks)
(lambda (success-k fail-k max-depth tasks)
(fail-k max-depth tasks)))
(report-answer-all answer-key
max-depth
tasks
null
(λ (max-depth tasks)
(fail-k max-depth tasks))))
(k end max-depth tasks new-got-k new-fail-k))]))))
(lambda (max-depth tasks)
(fail-k max-depth tasks))))])
(k end max-depth tasks new-got-k new-fail-k)))])))))
;; These temp identifiers can't be `gensym` or `generate-temporary`
;; because they have to be consistent between module loads
@ -458,34 +497,39 @@
(define-for-syntax atok-id-temp 'atok_wrutdjgecmybyfipiwsgjlvsveryodlgassuzcargiuznzgdghrykfqfbwcjgzdhdoeqxcucmtjkuyucskzethozhqkasphdwbht)
(define-syntax (cfg-parser stx)
(syntax-case stx ()
[(_ CLAUSE ...)
(let ([clauses (syntax->list #'(CLAUSE ...))])
[(_ clause ...)
(let ([clauses (syntax->list #'(clause ...))])
(let-values ([(start grammar cfg-error parser-clauses src-pos?)
(let ([all-toks (apply
append
(for/list ([clause (in-list clauses)])
(map (lambda (clause)
(syntax-case clause (tokens)
[(tokens T ...)
[(tokens t ...)
(apply
append
(for/list ([t (in-list (syntax->list #'(T ...)))])
(define v (syntax-local-value t (λ () #f)))
(map (lambda (t)
(let ([v (syntax-local-value t (lambda () #f))])
(cond
[(terminals-def? v)
(for/list ([v (in-list (syntax->list (terminals-def-t v)))])
(cons v #f))]
(map (lambda (v)
(cons v #f))
(syntax->list (terminals-def-t v)))]
[(e-terminals-def? v)
(for/list ([v (in-list (syntax->list (e-terminals-def-t v)))])
(cons v #t))]
[else null])))]
[_else null])))]
(map (lambda (v)
(cons v #t))
(syntax->list (e-terminals-def-t v)))]
[else null])))
(syntax->list #'(t ...))))]
[_else null]))
clauses))]
[all-end-toks (apply
append
(for/list ([clause (in-list clauses)])
(map (lambda (clause)
(syntax-case clause (end)
[(end T ...)
(syntax->list #'(T ...))]
[_else null])))])
[(end t ...)
(syntax->list #'(t ...))]
[_else null]))
clauses))])
(let loop ([clauses clauses]
[cfg-start #f]
[cfg-grammar #f]
@ -499,35 +543,47 @@
(reverse parser-clauses)
src-pos?)
(syntax-case (car clauses) (start error grammar src-pos)
[(start TOK)
(loop (cdr clauses) #'TOK cfg-grammar cfg-error src-pos? parser-clauses)]
[(error EXPR)
(loop (cdr clauses) cfg-start cfg-grammar #'EXPR src-pos? parser-clauses)]
[(grammar [NT [PAT HANDLE0 HANDLE ...] ...] ...)
[(start tok)
(loop (cdr clauses) #'tok cfg-grammar cfg-error src-pos? parser-clauses)]
[(error expr)
(loop (cdr clauses) cfg-start cfg-grammar #'expr src-pos? parser-clauses)]
[(grammar [nt [pat handle0 handle ...] ...] ...)
(let ([nts (make-bound-identifier-mapping)]
[toks (make-token-identifier-mapping)]
[end-toks (make-token-identifier-mapping)]
[nt-ids (syntax->list #'(NT ...))]
[patss (map (λ (stx)
[nt-ids (syntax->list #'(nt ...))]
[patss (map (lambda (stx)
(map syntax->list (syntax->list stx)))
(syntax->list #'((PAT ...) ...)))])
(for ([nt (in-list nt-ids)])
(syntax->list #'((pat ...) ...)))])
(for-each (lambda (nt)
(bound-identifier-mapping-put! nts nt (list 0)))
(for ([t (in-list all-end-toks)])
nt-ids)
(for-each (lambda (t)
(token-identifier-mapping-put! end-toks t #t))
(for ([t (in-list all-toks)]
#:unless (token-identifier-mapping-get end-toks (car t) (λ () #f)))
(define id (gensym (syntax-e (car t))))
(token-identifier-mapping-put! toks (car t) (cons id (cdr t))))
all-end-toks)
(for-each (lambda (t)
(unless (token-identifier-mapping-get end-toks (car t) (lambda () #f))
(let ([id (gensym (syntax-e (car t)))])
(token-identifier-mapping-put! toks (car t)
(cons id (cdr t))))))
all-toks)
;; Compute min max size for each non-term:
(nt-fixpoint
nts
(λ (nt pats old-list)
(lambda (nt pats old-list)
(let ([new-cnt
(apply min (for/list ([pat (in-list pats)])
(for/sum ([elem (in-list pat)])
(car (bound-identifier-mapping-get
nts elem (λ () (list 1)))))))])
(apply
min
(map (lambda (pat)
(apply
+
(map (lambda (elem)
(car
(bound-identifier-mapping-get nts
elem
(lambda () (list 1)))))
pat)))
pats))])
(if (new-cnt . > . (car old-list))
(cons new-cnt (cdr old-list))
old-list)))
@ -536,17 +592,17 @@
;; for a non-terminal
(nt-fixpoint
nts
(λ (nt pats old-list)
(lambda (nt pats old-list)
(let ([new-list
(apply
append
(for/list ([pat (in-list pats)])
(map (lambda (pat)
(let loop ([pat pat])
(if (pair? pat)
(let ([l (bound-identifier-mapping-get
nts
(car pat)
(λ ()
(lambda ()
(list 1 (map-token toks (car pat)))))])
;; If the non-terminal can match 0 things,
;; then it might match something from the
@ -555,9 +611,10 @@
(if (zero? (car l))
(append (cdr l) (loop (cdr pat)))
(cdr l)))
null))))])
(let ([new (filter (λ (id)
(andmap (λ (id2)
null)))
pats))])
(let ([new (filter (lambda (id)
(andmap (lambda (id2)
(not (eq? id id2)))
(cdr old-list)))
new-list)])
@ -566,7 +623,7 @@
(let ([new (let loop ([new new])
(if (null? (cdr new))
new
(if (ormap (λ (id)
(if (ormap (lambda (id)
(eq? (car new) id))
(cdr new))
(loop (cdr new))
@ -575,26 +632,26 @@
old-list))))
nt-ids patss)
;; Determine left-recursive clauses:
(for-each (λ (nt pats)
(for-each (lambda (nt pats)
(let ([l (bound-identifier-mapping-get nts nt)])
(bound-identifier-mapping-put! nts nt (list (car l)
(cdr l)
(map (λ (x) #f) pats)))))
(map (lambda (x) #f) pats)))))
nt-ids patss)
(nt-fixpoint
nts
(λ (nt pats old-list)
(lambda (nt pats old-list)
(list (car old-list)
(cadr old-list)
(map (λ (pat simple?)
(map (lambda (pat simple?)
(or simple?
(let ([l (map (λ (elem)
(let ([l (map (lambda (elem)
(bound-identifier-mapping-get
nts
elem
(λ () #f)))
(lambda () #f)))
pat)])
(andmap (λ (i)
(andmap (lambda (i)
(or (not i)
(andmap values (caddr i))))
l))))
@ -603,16 +660,16 @@
;; Build a definition for each non-term:
(loop (cdr clauses)
cfg-start
(map (λ (nt pats handles $ctxs)
(map (lambda (nt pats handles $ctxs)
(define info (bound-identifier-mapping-get nts nt))
(list nt
#`(let ([key (gensym '#,nt)])
(λ (stream last-consumed-token depth end success-k fail-k max-depth tasks)
(lambda (stream last-consumed-token depth end success-k fail-k max-depth tasks)
(parse-nt/share
key #,(car info) '#,(cadr info) stream last-consumed-token depth end
max-depth tasks
success-k fail-k
(λ (end max-depth tasks success-k fail-k)
(lambda (end max-depth tasks success-k fail-k)
#,(let loop ([pats pats]
[handles (syntax->list handles)]
[$ctxs (syntax->list $ctxs)]
@ -623,13 +680,13 @@
(car simple?s))
#'parse-or
#'parse-parallel-or)
(λ (stream last-consumed-token depth end success-k fail-k max-depth tasks)
(lambda (stream last-consumed-token depth end success-k fail-k max-depth tasks)
#,(build-match nts
toks
(car pats)
(car handles)
(car $ctxs)))
(λ (stream last-consumed-token depth end success-k fail-k max-depth tasks)
(lambda (stream last-consumed-token depth end success-k fail-k max-depth tasks)
#,(loop (cdr pats)
(cdr handles)
(cdr $ctxs)
@ -637,14 +694,14 @@
stream last-consumed-token depth end success-k fail-k max-depth tasks)))))))))
nt-ids
patss
(syntax->list #'(((begin HANDLE0 HANDLE ...) ...) ...))
(syntax->list #'((HANDLE0 ...) ...)))
(syntax->list #'(((begin handle0 handle ...) ...) ...))
(syntax->list #'((handle0 ...) ...)))
cfg-error
src-pos?
(list*
(with-syntax ([((tok tok-id . $e) ...)
(token-identifier-mapping-map toks
(λ (k v)
(lambda (k v)
(list* k
(car v)
(if (cdr v)
@ -686,23 +743,29 @@
src-pos?
(cons (car clauses) parser-clauses))]))))])
#`(let ([orig-parse (parser
[error (λ (a b c)
[error (lambda (a b c)
(error 'cfg-parser "unexpected ~a token: ~a" b c))]
. #,parser-clauses)]
[error-proc #,cfg-error])
(letrec #,grammar
(λ (get-tok)
(lambda (get-tok)
(let ([tok-list (orig-parse get-tok)])
(letrec ([success-k
(λ (val stream last-consumed-token depth max-depth tasks next)
(lambda (val stream last-consumed-token depth max-depth tasks next)
(if (null? stream)
val
(next success-k fail-k max-depth tasks)))]
[fail-k (λ (max-depth tasks)
[fail-k (lambda (max-depth tasks)
(define (call-error-proc tok-ok? tok-name tok-value start-pos end-pos)
(cond
[(procedure-arity-includes? error-proc 5)
(error-proc tok-ok? tok-name tok-value start-pos end-pos)]
[else
(error-proc tok-ok? tok-name tok-value)]))
(cond
[(null? tok-list)
(if error-proc
(error-proc #t
(call-error-proc #t
'no-tokens
#f
(make-position #f #f #f)
@ -715,7 +778,7 @@
(min (sub1 (length tok-list))
max-depth))])
(if error-proc
(error-proc #t
(call-error-proc #t
(tok-orig-name bad-tok)
(tok-val bad-tok)
(tok-start bad-tok)
@ -752,8 +815,9 @@
(module* test racket/base
(require (submod "..")
br-parser-tools/lex
parser-tools/lex
racket/block
racket/generator
rackunit)
;; Test: parsing regular expressions.
@ -790,7 +854,7 @@
(define (parse s)
(define ip (open-input-string s))
(port-count-lines! ip)
(-parse (λ () (lex ip))))
(-parse (lambda () (lex ip))))
(check-equal? (parse "abc")
'(unanchored (lit "abc" 1 4) 1 4))
@ -803,6 +867,60 @@
1 13)))
;; Check that cfg-parser can accept error functions of 3 arguments:
(block
(define-tokens non-terminals (ONE ZERO EOF))
(define parse
(cfg-parser (tokens non-terminals)
(start ones)
(end EOF)
(error (lambda (tok-ok tok-name tok-val)
(error (format "~a ~a ~a" tok-ok tok-name tok-val))))
(grammar [ones [() null]
[(ONE ones) (cons $1 $2)]])))
(define (sequence->tokenizer s)
(define-values (more? next) (sequence-generate s))
(lambda ()
(cond [(more?) (next)]
[else (token-EOF 'eof)])))
(check-exn #rx"#t ZERO zero"
(lambda () (parse (sequence->tokenizer (list (token-ZERO "zero")))))))
;; Check that cfg-parser can accept error functions of 5 arguments:
(block
(define-tokens non-terminals (ONE ZERO EOF))
(define parse
(cfg-parser (tokens non-terminals)
(start ones)
(src-pos)
(end EOF)
(error (lambda (tok-ok tok-name tok-val start-pos end-pos)
(error (format "~a ~a ~a ~a ~a"
tok-ok tok-name tok-val
(position-offset start-pos)
(position-offset end-pos)))))
(grammar [ones [() null]
[(ONE ones) (cons $1 $2)]])))
(define (sequence->tokenizer s)
(define-values (more? next) (sequence-generate s))
(lambda ()
(cond [(more?) (next)]
[else (position-token (token-EOF 'eof)
(position #f #f #f)
(position #f #f #f))])))
(check-exn #rx"#t ZERO zero 2 3"
(lambda ()
(parse
(sequence->tokenizer
(list (position-token
(token-ZERO "zero")
(position 2 2 5)
(position 3 2 6))))))))
@ -824,7 +942,7 @@
(tokens non-terminals)
(start <program>)
(end EOF)
(error (λ (a b stx)
(error (lambda (a b stx)
(error 'parse "failed at ~s" stx)))
(grammar [<program> [(PLUS) "plus"]
[(<minus-program> BAR <minus-program>) (list $1 $2 $3)]
@ -846,7 +964,7 @@
-|-*|-|-**|-|-*|-|-***|-|-*|-|-**|-|-*|-|-*****"
;; This one fails:
#;"+*")])
(check-equal? (parse (λ () (lex p)))
(check-equal? (parse (lambda () (lex p)))
'((((((((((("minus" || "minus") . *) || (("minus" || "minus") . *)) . *) || (((("minus" || "minus") . *) || (("minus" || "minus") . *)) . *)) . *)
||
(((((("minus" || "minus") . *) || (("minus" || "minus") . *)) . *) || (((("minus" || "minus") . *) || (("minus" || "minus") . *)) . *)) . *))

31
br-parser-tools-lib/br-parser-tools/examples/calc.rkt → parser-tools-lib/parser-tools/examples/calc.rkt
Unescape Escape View File

@ -1,12 +1,12 @@
#lang racket/base
#lang scheme
;; An interactive calculator inspired by the calculator example in the bison manual.
;; Import the parser and lexer generators.
(require br-parser-tools/yacc
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre))
(require parser-tools/yacc
parser-tools/lex
(prefix-in : parser-tools/lex-sre))
(define-tokens value-tokens (NUM VAR FNCT))
(define-empty-tokens op-tokens (newline = OP CP + - * / ^ EOF NEG))
@ -22,12 +22,12 @@
;; (:/ 0 9) would not work because the lexer does not understand numbers. (:/ #\0 #\9) is ok too.
(digit (:/ "0" "9")))
(define calc-lex
(define calcl
(lexer
[(eof) 'EOF]
;; recursively call the lexer on the remaining input after a tab or space. Returning the
;; result of that operation. This effectively skips all whitespace.
[(:or #\tab #\space) (calc-lex input-port)]
[(:or #\tab #\space) (calcl input-port)]
;; (token-newline) returns 'newline
[#\newline (token-newline)]
;; Since (token-=) returns '=, just return the symbol directly
@ -40,7 +40,7 @@
[(:: (:+ digit) #\. (:* digit)) (token-NUM (string->number lexeme))]))
(define calc-parse
(define calcp
(parser
(start start)
@ -78,15 +78,12 @@
;; run the calculator on the given input-port
(define (calc ip)
(port-count-lines! ip)
(let loop ()
(define result (calc-parse (λ () (calc-lex ip))))
(letrec ((one-line
(lambda ()
(let ((result (calcp (lambda () (calcl ip)))))
(when result
(printf "~a\n" result)
(loop))))
(module+ test
(require rackunit)
(check-equal? (let ([o (open-output-string)])
(parameterize ([current-output-port o])
(calc (open-input-string "x=1\n(x + 2 * 3) - (1+2)*3")))
(get-output-string o)) "1\n-2\n"))
(one-line))))))
(one-line)))
(calc (open-input-string "x=1\n(x + 2 * 3) - (1+2)*3"))

242
parser-tools-lib/parser-tools/examples/read.rkt
Unescape Escape View File

@ -0,0 +1,242 @@
;; This implements the equivalent of racket's read-syntax for R5RS scheme.
;; It has not been thoroughly tested. Also it will read an entire file into a
;; list of syntax objects, instead of returning one syntax object at a time
(module read mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre)
parser-tools/yacc
syntax/readerr)
(define-tokens data (DATUM))
(define-empty-tokens delim (OP CP HASHOP QUOTE QUASIQUOTE UNQUOTE UNQUOTE-SPLICING DOT EOF))
(define scheme-lexer
(lexer-src-pos
;; Skip comments, without accumulating extra position information
[(:or scheme-whitespace comment) (return-without-pos (scheme-lexer input-port))]
["#t" (token-DATUM #t)]
["#f" (token-DATUM #f)]
[(:: "#\\" any-char) (token-DATUM (caddr (string->list lexeme)))]
["#\\space" (token-DATUM #\space)]
["#\\newline" (token-DATUM #\newline)]
[(:or (:: initial (:* subsequent)) "+" "-" "...") (token-DATUM (string->symbol lexeme))]
[#\" (token-DATUM (list->string (get-string-token input-port)))]
[#\( 'OP]
[#\) 'CP]
[#\[ 'OP]
[#\] 'CP]
["#(" 'HASHOP]
[num2 (token-DATUM (string->number lexeme 2))]
[num8 (token-DATUM (string->number lexeme 8))]
[num10 (token-DATUM (string->number lexeme 10))]
[num16 (token-DATUM (string->number lexeme 16))]
["'" 'QUOTE]
["`" 'QUASIQUOTE]
["," 'UNQUOTE]
[",@" 'UNQUOTE-SPLICING]
["." 'DOT]
[(eof) 'EOF]))
(define get-string-token
(lexer
[(:~ #\" #\\) (cons (car (string->list lexeme))
(get-string-token input-port))]
[(:: #\\ #\\) (cons #\\ (get-string-token input-port))]
[(:: #\\ #\") (cons #\" (get-string-token input-port))]
[#\" null]))
(define-lex-abbrevs
[letter (:or (:/ "a" "z") (:/ #\A #\Z))]
[digit (:/ #\0 #\9)]
[scheme-whitespace (:or #\newline #\return #\tab #\space #\vtab)]
[initial (:or letter (char-set "!$%&*/:<=>?^_~@"))]
[subsequent (:or initial digit (char-set "+-.@"))]
[comment (:: #\; (:* (:~ #\newline)) #\newline)]
;; See ${PLTHOME}/collects/syntax-color/racket-lexer.rkt for an example of
;; using regexp macros to avoid the cut and paste.
; [numR (:: prefixR complexR)]
; [complexR (:or realR
; (:: realR "@" realR)
; (:: realR "+" urealR "i")
; (:: realR "-" urealR "i")
; (:: realR "+i")
; (:: realR "-i")
; (:: "+" urealR "i")
; (:: "-" urealR "i")
; (:: "+i")
; (:: "-i"))]
; [realR (:: sign urealR)]
; [urealR (:or uintegerR (:: uintegerR "/" uintegerR) decimalR)]
; [uintegerR (:: (:+ digitR) (:* #\#))]
; [prefixR (:or (:: radixR exactness)
; (:: exactness radixR))]
[num2 (:: prefix2 complex2)]
[complex2 (:or real2
(:: real2 "@" real2)
(:: real2 "+" ureal2 "i")
(:: real2 "-" ureal2 "i")
(:: real2 "+i")
(:: real2 "-i")
(:: "+" ureal2 "i")
(:: "-" ureal2 "i")
(:: "+i")
(:: "-i"))]
[real2 (:: sign ureal2)]
[ureal2 (:or uinteger2 (:: uinteger2 "/" uinteger2))]
[uinteger2 (:: (:+ digit2) (:* #\#))]
[prefix2 (:or (:: radix2 exactness)
(:: exactness radix2))]
[radix2 "#b"]
[digit2 (:or "0" "1")]
[num8 (:: prefix8 complex8)]
[complex8 (:or real8
(:: real8 "@" real8)
(:: real8 "+" ureal8 "i")
(:: real8 "-" ureal8 "i")
(:: real8 "+i")
(:: real8 "-i")
(:: "+" ureal8 "i")
(:: "-" ureal8 "i")
(:: "+i")
(:: "-i"))]
[real8 (:: sign ureal8)]
[ureal8 (:or uinteger8 (:: uinteger8 "/" uinteger8))]
[uinteger8 (:: (:+ digit8) (:* #\#))]
[prefix8 (:or (:: radix8 exactness)
(:: exactness radix8))]
[radix8 "#o"]
[digit8 (:/ "0" "7")]
[num10 (:: prefix10 complex10)]
[complex10 (:or real10
(:: real10 "@" real10)
(:: real10 "+" ureal10 "i")
(:: real10 "-" ureal10 "i")
(:: real10 "+i")
(:: real10 "-i")
(:: "+" ureal10 "i")
(:: "-" ureal10 "i")
(:: "+i")
(:: "-i"))]
[real10 (:: sign ureal10)]
[ureal10 (:or uinteger10 (:: uinteger10 "/" uinteger10) decimal10)]
[uinteger10 (:: (:+ digit10) (:* #\#))]
[prefix10 (:or (:: radix10 exactness)
(:: exactness radix10))]
[radix10 (:? "#d")]
[digit10 digit]
[decimal10 (:or (:: uinteger10 suffix)
(:: #\. (:+ digit10) (:* #\#) suffix)
(:: (:+ digit10) #\. (:* digit10) (:* #\#) suffix)
(:: (:+ digit10) (:+ #\#) #\. (:* #\#) suffix))]
[num16 (:: prefix16 complex16)]
[complex16 (:or real16
(:: real16 "@" real16)
(:: real16 "+" ureal16 "i")
(:: real16 "-" ureal16 "i")
(:: real16 "+i")
(:: real16 "-i")
(:: "+" ureal16 "i")
(:: "-" ureal16 "i")
"+i"
"-i")]
[real16 (:: sign ureal16)]
[ureal16 (:or uinteger16 (:: uinteger16 "/" uinteger16))]
[uinteger16 (:: (:+ digit16) (:* #\#))]
[prefix16 (:or (:: radix16 exactness)
(:: exactness radix16))]
[radix16 "#x"]
[digit16 (:or digit (:/ #\a #\f) (:/ #\A #\F))]
[suffix (:or "" (:: exponent-marker sign (:+ digit10)))]
[exponent-marker (:or "e" "s" "f" "d" "l")]
[sign (:or "" "+" "-")]
[exactness (:or "" "#i" "#e")])
(define stx-for-original-property (read-syntax #f (open-input-string "original")))
;; A macro to build the syntax object
(define-syntax (build-so stx)
(syntax-case stx ()
((_ value start end)
(with-syntax ((start-pos (datum->syntax-object
(syntax end)
(string->symbol
(format "$~a-start-pos"
(syntax-object->datum (syntax start))))))
(end-pos (datum->syntax-object
(syntax end)
(string->symbol
(format "$~a-end-pos"
(syntax-object->datum (syntax end))))))
(source (datum->syntax-object
(syntax end)
'source-name)))
(syntax
(datum->syntax-object
#f
value
(list source
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos)
(position-offset start-pos)))
stx-for-original-property))))))
(define (scheme-parser source-name)
(parser
(src-pos)
(start s)
(end EOF)
(error (lambda (a name val start end)
(raise-read-error
"read-error"
source-name
(position-line start)
(position-col start)
(position-offset start)
(- (position-offset end)
(position-offset start)))))
(tokens data delim)
(grammar
(s [(sexp-list) (reverse $1)])
(sexp [(DATUM) (build-so $1 1 1)]
[(OP sexp-list CP) (build-so (reverse $2) 1 3)]
[(HASHOP sexp-list CP) (build-so (list->vector (reverse $2)) 1 3)]
[(QUOTE sexp) (build-so (list 'quote $2) 1 2)]
[(QUASIQUOTE sexp) (build-so (list 'quasiquote $2) 1 2)]
[(UNQUOTE sexp) (build-so (list 'unquote $2) 1 2)]
[(UNQUOTE-SPLICING sexp) (build-so (list 'unquote-splicing $2) 1 2)]
[(OP sexp-list DOT sexp CP) (build-so (append (reverse $2) $4) 1 5)])
(sexp-list [() null]
[(sexp-list sexp) (cons $2 $1)]))))
(define (rs sn ip)
(port-count-lines! ip)
((scheme-parser sn) (lambda () (scheme-lexer ip))))
(define readsyntax
(case-lambda ((sn) (rs sn (current-input-port)))
((sn ip) (rs sn ip))))
(provide (rename readsyntax read-syntax))
)

0
br-parser-tools-lib/br-parser-tools/info.rkt → parser-tools-lib/parser-tools/info.rkt
Unescape Escape View File

24
parser-tools-lib/parser-tools/lex-plt-v200.rkt
Unescape Escape View File

@ -0,0 +1,24 @@
(module lex-plt-v200 mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre))
(provide epsilon
~
(rename :* *)
(rename :+ +)
(rename :? ?)
(rename :or :)
(rename :& &)
(rename :: @)
(rename :~ ^)
(rename :/ -))
(define-lex-trans epsilon
(syntax-rules ()
((_) "")))
(define-lex-trans ~
(syntax-rules ()
((_ re) (complement re)))))

119
parser-tools-lib/parser-tools/lex-sre.rkt
Unescape Escape View File

@ -0,0 +1,119 @@
(module lex-sre mzscheme
(require parser-tools/lex)
(provide (rename sre-* *)
(rename sre-+ +)
?
(rename sre-= =)
(rename sre->= >=)
**
(rename sre-or or)
:
seq
&
~
(rename sre-- -)
(rename sre-/ /)
/-only-chars)
(define-lex-trans sre-*
(syntax-rules ()
((_ re ...)
(repetition 0 +inf.0 (union re ...)))))
(define-lex-trans sre-+
(syntax-rules ()
((_ re ...)
(repetition 1 +inf.0 (union re ...)))))
(define-lex-trans ?
(syntax-rules ()
((_ re ...)
(repetition 0 1 (union re ...)))))
(define-lex-trans sre-=
(syntax-rules ()
((_ n re ...)
(repetition n n (union re ...)))))
(define-lex-trans sre->=
(syntax-rules ()
((_ n re ...)
(repetition n +inf.0 (union re ...)))))
(define-lex-trans **
(syntax-rules ()
((_ low #f re ...)
(** low +inf.0 re ...))
((_ low high re ...)
(repetition low high (union re ...)))))
(define-lex-trans sre-or
(syntax-rules ()
((_ re ...)
(union re ...))))
(define-lex-trans :
(syntax-rules ()
((_ re ...)
(concatenation re ...))))
(define-lex-trans seq
(syntax-rules ()
((_ re ...)
(concatenation re ...))))
(define-lex-trans &
(syntax-rules ()
((_ re ...)
(intersection re ...))))
(define-lex-trans ~
(syntax-rules ()
((_ re ...)
(char-complement (union re ...)))))
;; set difference
(define-lex-trans (sre-- stx)
(syntax-case stx ()
((_)
(raise-syntax-error #f
"must have at least one argument"
stx))
((_ big-re re ...)
(syntax (& big-re (complement (union re ...)))))))
(define-lex-trans (sre-/ stx)
(syntax-case stx ()
((_ range ...)
(let ((chars
(apply append (map (lambda (r)
(let ((x (syntax-e r)))
(cond
((char? x) (list x))
((string? x) (string->list x))
(else
(raise-syntax-error
#f
"not a char or string"
stx
r)))))
(syntax->list (syntax (range ...)))))))
(unless (even? (length chars))
(raise-syntax-error
#f
"not given an even number of characters"
stx))
#`(/-only-chars #,@chars)))))
(define-lex-trans /-only-chars
(syntax-rules ()
((_ c1 c2)
(char-range c1 c2))
((_ c1 c2 c ...)
(union (char-range c1 c2)
(/-only-chars c ...)))))
)

393
parser-tools-lib/parser-tools/lex.rkt
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@ -0,0 +1,393 @@
(module lex mzscheme
;; Provides the syntax used to create lexers and the functions needed to
;; create and use the buffer that the lexer reads from. See docs.
(require-for-syntax mzlib/list
syntax/stx
syntax/define
syntax/boundmap
"private-lex/util.rkt"
"private-lex/actions.rkt"
"private-lex/front.rkt"
"private-lex/unicode-chars.rkt")
(require mzlib/stxparam
syntax/readerr
"private-lex/token.rkt")
(provide lexer lexer-src-pos define-lex-abbrev define-lex-abbrevs define-lex-trans
;; Dealing with tokens and related structures
define-tokens define-empty-tokens token-name token-value token?
(struct position (offset line col))
(struct position-token (token start-pos end-pos))
;; File path for highlighting errors while lexing
file-path
;; Lex abbrevs for unicode char sets. See mzscheme manual section 3.4.
any-char any-string nothing alphabetic lower-case upper-case title-case
numeric symbolic punctuation graphic whitespace blank iso-control
;; A regular expression operator
char-set)
;; wrap-action: syntax-object src-pos? -> syntax-object
(define-for-syntax (wrap-action action src-pos?)
(with-syntax ((action-stx
(if src-pos?
#`(let/ec ret
(syntax-parameterize
((return-without-pos (make-rename-transformer #'ret)))
(make-position-token #,action start-pos end-pos)))
action)))
(syntax/loc action
(lambda (start-pos-p end-pos-p lexeme-p input-port-p)
(syntax-parameterize
((start-pos (make-rename-transformer #'start-pos-p))
(end-pos (make-rename-transformer #'end-pos-p))
(lexeme (make-rename-transformer #'lexeme-p))
(input-port (make-rename-transformer #'input-port-p)))
action-stx)))))
(define-for-syntax (make-lexer-trans src-pos?)
(lambda (stx)
(syntax-case stx ()
((_ re-act ...)
(begin
(for-each
(lambda (x)
(syntax-case x ()
((re act) (void))
(_ (raise-syntax-error #f
"not a regular expression / action pair"
stx
x))))
(syntax->list (syntax (re-act ...))))
(let* ((spec/re-act-lst
(syntax->list (syntax (re-act ...))))
(eof-act
(get-special-action spec/re-act-lst #'eof #''eof))
(spec-act
(get-special-action spec/re-act-lst #'special #'(void)))
(spec-comment-act
(get-special-action spec/re-act-lst #'special-comment #'#f))
(ids (list #'special #'special-comment #'eof))
(re-act-lst
(filter
(lambda (spec/re-act)
(syntax-case spec/re-act ()
(((special) act)
(not (ormap
(lambda (x)
(and (identifier? #'special)
(module-or-top-identifier=? (syntax special) x)))
ids)))
(_ #t)))
spec/re-act-lst))
(name-lst (map (lambda (x) (datum->syntax-object #f (gensym))) re-act-lst))
(act-lst (map (lambda (x) (stx-car (stx-cdr x))) re-act-lst))
(re-actname-lst (map (lambda (re-act name)
(list (stx-car re-act)
name))
re-act-lst
name-lst)))
(when (null? spec/re-act-lst)
(raise-syntax-error (if src-pos? 'lexer/src-pos 'lexer) "expected at least one action" stx))
(let-values (((trans start action-names no-look disappeared-uses)
(build-lexer re-actname-lst)))
(when (vector-ref action-names start) ;; Start state is final
(unless (and
;; All the successor states are final
(andmap (lambda (x) (vector-ref action-names (vector-ref x 2)))
(vector->list (vector-ref trans start)))
;; Each character has a successor state
(let loop ((check 0)
(nexts (vector->list (vector-ref trans start))))
(cond
((null? nexts) #f)
(else
(let ((next (car nexts)))
(and (= (vector-ref next 0) check)
(let ((next-check (vector-ref next 1)))
(or (>= next-check max-char-num)
(loop (add1 next-check) (cdr nexts))))))))))
(eprintf "Warning: lexer at ~a can accept the empty string.\n" stx)))
(with-syntax ((start-state-stx start)
(trans-table-stx trans)
(no-lookahead-stx no-look)
((name ...) name-lst)
((act ...) (map (lambda (a)
(wrap-action a src-pos?))
act-lst))
((act-name ...) (vector->list action-names))
(spec-act-stx
(wrap-action spec-act src-pos?))
(has-comment-act?-stx
(if (syntax-e spec-comment-act) #t #f))
(spec-comment-act-stx
(wrap-action spec-comment-act src-pos?))
(eof-act-stx (wrap-action eof-act src-pos?)))
(syntax-property
(syntax/loc stx
(let ([name act] ...)
(let ([proc
(lexer-body start-state-stx
trans-table-stx
(vector act-name ...)
no-lookahead-stx
spec-act-stx
has-comment-act?-stx
spec-comment-act-stx
eof-act-stx)])
;; reverse eta to get named procedures:
(lambda (port) (proc port)))))
'disappeared-use
disappeared-uses)))))))))
(define-syntax lexer (make-lexer-trans #f))
(define-syntax lexer-src-pos (make-lexer-trans #t))
(define-syntax (define-lex-abbrev stx)
(syntax-case stx ()
((_ name re)
(identifier? (syntax name))
(syntax/loc stx
(define-syntax name
(make-lex-abbrev (lambda () (quote-syntax re))))))
(_
(raise-syntax-error
#f
"form should be (define-lex-abbrev name re)"
stx))))
(define-syntax (define-lex-abbrevs stx)
(syntax-case stx ()
((_ x ...)
(with-syntax (((abbrev ...)
(map
(lambda (a)
(syntax-case a ()
((name re)
(identifier? (syntax name))
(syntax/loc a (define-lex-abbrev name re)))
(_ (raise-syntax-error
#f
"form should be (define-lex-abbrevs (name re) ...)"
stx
a))))
(syntax->list (syntax (x ...))))))
(syntax/loc stx (begin abbrev ...))))
(_
(raise-syntax-error
#f
"form should be (define-lex-abbrevs (name re) ...)"
stx))))
(define-syntax (define-lex-trans stx)
(syntax-case stx ()
((_ name-form body-form)
(let-values (((name body)
(normalize-definition (syntax (define-syntax name-form body-form)) #'lambda)))
#`(define-syntax #,name
(let ((func #,body))
(unless (procedure? func)
(raise-syntax-error 'define-lex-trans "expected a procedure as the transformer, got ~e" func))
(unless (procedure-arity-includes? func 1)
(raise-syntax-error 'define-lex-trans "expected a procedure that accepts 1 argument as the transformer, got ~e" func))
(make-lex-trans func)))))
(_
(raise-syntax-error
#f
"form should be (define-lex-trans name transformer)"
stx))))
(define (get-next-state-helper char min max table)
(if (>= min max)
#f
(let* ((try (quotient (+ min max) 2))
(el (vector-ref table try))
(r1 (vector-ref el 0))
(r2 (vector-ref el 1)))
(cond
((and (>= char r1) (<= char r2)) (vector-ref el 2))
((< char r1) (get-next-state-helper char min try table))
(else (get-next-state-helper char (add1 try) max table))))))
(define (get-next-state char table)
(if table
(get-next-state-helper char 0 (vector-length table) table)
#f))
(define (lexer-body start-state trans-table actions no-lookahead special-action
has-special-comment-action? special-comment-action eof-action)
(letrec ((lexer
(lambda (ip)
(let ((first-pos (get-position ip))
(first-char (peek-char-or-special ip 0)))
;(printf "(peek-char-or-special port 0) = ~e\n" first-char)
(cond
((eof-object? first-char)
(do-match ip first-pos eof-action (read-char-or-special ip)))
((special-comment? first-char)
(read-char-or-special ip)
(cond
(has-special-comment-action?
(do-match ip first-pos special-comment-action #f))
(else (lexer ip))))
((not (char? first-char))
(do-match ip first-pos special-action (read-char-or-special ip)))
(else
(let lexer-loop (
;; current-state
(state start-state)
;; the character to transition on
(char first-char)
;; action for the longest match seen thus far
;; including a match at the current state
(longest-match-action
(vector-ref actions start-state))
;; how many bytes precede char
(length-bytes 0)
;; how many characters have been read
;; including the one just read
(length-chars 1)
;; how many characters are in the longest match
(longest-match-length 0))
(let ((next-state
(cond
((not (char? char)) #f)
(else (get-next-state (char->integer char)
(vector-ref trans-table state))))))
(cond
((not next-state)
(check-match ip first-pos longest-match-length
length-chars longest-match-action))
((vector-ref no-lookahead next-state)
(let ((act (vector-ref actions next-state)))
(check-match ip
first-pos
(if act length-chars longest-match-length)
length-chars
(if act act longest-match-action))))
(else
(let* ((act (vector-ref actions next-state))
(next-length-bytes (+ (char-utf-8-length char) length-bytes))
(next-char (peek-char-or-special ip next-length-bytes)))
#;(printf "(peek-char-or-special port ~e) = ~e\n"
next-length-bytes next-char)
(lexer-loop next-state
next-char
(if act
act
longest-match-action)
next-length-bytes
(add1 length-chars)
(if act
length-chars
longest-match-length)))))))))))))
(lambda (ip)
(unless (input-port? ip)
(raise-argument-error
'lexer
"input-port?"
0
ip))
(lexer ip))))
(define (check-match lb first-pos longest-match-length length longest-match-action)
(unless longest-match-action
(let* ((match (read-string length lb))
(end-pos (get-position lb)))
(raise-read-error
(format "lexer: No match found in input starting with: ~a" match)
(file-path)
(position-line first-pos)
(position-col first-pos)
(position-offset first-pos)
(- (position-offset end-pos) (position-offset first-pos)))))
(let ((match (read-string longest-match-length lb)))
;(printf "(read-string ~e port) = ~e\n" longest-match-length match)
(do-match lb first-pos longest-match-action match)))
(define file-path (make-parameter #f))
(define (do-match ip first-pos action value)
#;(printf "(action ~a ~a ~a ~a)\n"
(position-offset first-pos) (position-offset (get-position ip)) value ip)
(action first-pos (get-position ip) value ip))
(define (get-position ip)
(let-values (((line col off) (port-next-location ip)))
(make-position off line col)))
(define-syntax (create-unicode-abbrevs stx)
(syntax-case stx ()
((_ ctxt)
(with-syntax (((ranges ...) (map (lambda (range)
`(union ,@(map (lambda (x)
`(char-range ,(integer->char (car x))
,(integer->char (cdr x))))
range)))
(list (force alphabetic-ranges)
(force lower-case-ranges)
(force upper-case-ranges)
(force title-case-ranges)
(force numeric-ranges)
(force symbolic-ranges)
(force punctuation-ranges)
(force graphic-ranges)
(force whitespace-ranges)
(force blank-ranges)
(force iso-control-ranges))))
((names ...) (map (lambda (sym)
(datum->syntax-object (syntax ctxt) sym #f))
'(alphabetic
lower-case
upper-case
title-case
numeric
symbolic
punctuation
graphic
whitespace
blank
iso-control))))
(syntax (define-lex-abbrevs (names ranges) ...))))))
(define-lex-abbrev any-char (char-complement (union)))
(define-lex-abbrev any-string (intersection))
(define-lex-abbrev nothing (union))
(create-unicode-abbrevs #'here)
(define-lex-trans (char-set stx)
(syntax-case stx ()
((_ str)
(string? (syntax-e (syntax str)))
(with-syntax (((char ...) (string->list (syntax-e (syntax str)))))
(syntax (union char ...))))))
(define-syntax provide-lex-keyword
(syntax-rules ()
[(_ id ...)
(begin
(define-syntax-parameter id
(make-set!-transformer
(lambda (stx)
(raise-syntax-error
#f
(format "use of a lexer keyword (~a) is not in an appropriate lexer action"
'id)
stx))))
...
(provide id ...))]))
(provide-lex-keyword start-pos end-pos lexeme input-port return-without-pos)
)

15
br-parser-tools-lib/br-parser-tools/private-lex/actions.rkt → parser-tools-lib/parser-tools/private-lex/actions.rkt
Unescape Escape View File

@ -1,4 +1,5 @@
#lang racket/base
#lang scheme/base
(provide (all-defined-out))
(require syntax/stx)
@ -6,10 +7,10 @@
;; Returns the first action from a rule of the form ((which-special) action)
(define (get-special-action rules which-special none)
(cond
[(null? rules) none]
[else
((null? rules) none)
(else
(syntax-case (car rules) ()
[((special) ACT)
(and (identifier? #'special) (module-or-top-identifier=? #'special which-special))
#'ACT]
[_ (get-special-action (cdr rules) which-special none)])]))
(((special) act)
(and (identifier? #'special) (module-or-top-identifier=? (syntax special) which-special))
(syntax act))
(_ (get-special-action (cdr rules) which-special none))))))

339
parser-tools-lib/parser-tools/private-lex/deriv.rkt
Unescape Escape View File

@ -0,0 +1,339 @@
(module deriv mzscheme
(require mzlib/list
(prefix is: mzlib/integer-set)
"re.rkt"
"util.rkt")
(provide build-dfa print-dfa (struct dfa (num-states start-state final-states/actions transitions)))
(define e (build-epsilon))
(define z (build-zero))
;; Don't do anything with this one but extract the chars
(define all-chars (->re `(char-complement (union)) (make-cache)))
;; get-char-groups : re bool -> (list-of char-setR?)
;; Collects the char-setRs in r that could be used in
;; taking the derivative of r.
(define (get-char-groups r found-negation)
(cond
((or (eq? r e) (eq? r z)) null)
((char-setR? r) (list r))
((concatR? r)
(if (re-nullable? (concatR-re1 r))
(append (get-char-groups (concatR-re1 r) found-negation)
(get-char-groups (concatR-re2 r) found-negation))
(get-char-groups (concatR-re1 r) found-negation)))
((repeatR? r)
(get-char-groups (repeatR-re r) found-negation))
((orR? r)
(apply append (map (lambda (x) (get-char-groups x found-negation)) (orR-res r))))
((andR? r)
(apply append (map (lambda (x) (get-char-groups x found-negation)) (andR-res r))))
((negR? r)
(if found-negation
(get-char-groups (negR-re r) #t)
(cons all-chars (get-char-groups (negR-re r) #t))))))
(test-block ((c (make-cache))
(r1 (->re #\1 c))
(r2 (->re #\2 c)))
((get-char-groups e #f) null)
((get-char-groups z #f) null)
((get-char-groups r1 #f) (list r1))
((get-char-groups (->re `(concatenation ,r1 ,r2) c) #f)
(list r1))
((get-char-groups (->re `(concatenation ,e ,r2) c) #f)
(list r2))
((get-char-groups (->re `(concatenation (repetition 0 +inf.0 ,r1) ,r2) c) #f)
(list r1 r2))
((get-char-groups (->re `(repetition 0 +inf.0 ,r1) c) #f)
(list r1))
((get-char-groups
(->re `(union (repetition 0 +inf.0 ,r1)
(concatenation (repetition 0 +inf.0 ,r2) "3") "4") c) #f)
(list r1 r2 (->re "3" c) (->re "4" c)))
((get-char-groups (->re `(complement ,r1) c) #f)
(list all-chars r1))
((get-char-groups
(->re `(intersection (repetition 0 +inf.0 ,r1)
(concatenation (repetition 0 +inf.0 ,r2) "3") "4") c) #f)
(list r1 r2 (->re "3" c) (->re "4" c)))
)
(define loc:member? is:member?)
;; deriveR : re char cache -> re
(define (deriveR r c cache)
(cond
((or (eq? r e) (eq? r z)) z)
((char-setR? r)
(if (loc:member? c (char-setR-chars r)) e z))
((concatR? r)
(let* ((r1 (concatR-re1 r))
(r2 (concatR-re2 r))
(d (build-concat (deriveR r1 c cache) r2 cache)))
(if (re-nullable? r1)
(build-or (list d (deriveR r2 c cache)) cache)
d)))
((repeatR? r)
(build-concat (deriveR (repeatR-re r) c cache)
(build-repeat (sub1 (repeatR-low r))
(sub1 (repeatR-high r))
(repeatR-re r) cache)
cache))
((orR? r)
(build-or (map (lambda (x) (deriveR x c cache))
(orR-res r))
cache))
((andR? r)
(build-and (map (lambda (x) (deriveR x c cache))
(andR-res r))
cache))
((negR? r)
(build-neg (deriveR (negR-re r) c cache) cache))))
(test-block ((c (make-cache))
(a (char->integer #\a))
(b (char->integer #\b))
(r1 (->re #\a c))
(r2 (->re `(repetition 0 +inf.0 #\a) c))
(r3 (->re `(repetition 0 +inf.0 ,r2) c))
(r4 (->re `(concatenation #\a ,r2) c))
(r5 (->re `(repetition 0 +inf.0 ,r4) c))
(r6 (->re `(union ,r5 #\a) c))
(r7 (->re `(concatenation ,r2 ,r2) c))
(r8 (->re `(complement ,r4) c))
(r9 (->re `(intersection ,r2 ,r4) c)))
((deriveR e a c) z)
((deriveR z a c) z)
((deriveR r1 b c) z)
((deriveR r1 a c) e)
((deriveR r2 a c) r2)
((deriveR r2 b c) z)
((deriveR r3 a c) r2)
((deriveR r3 b c) z)
((deriveR r4 a c) r2)
((deriveR r4 b c) z)
((deriveR r5 a c) (->re `(concatenation ,r2 ,r5) c))
((deriveR r5 b c) z)
((deriveR r6 a c) (->re `(union (concatenation ,r2 ,r5) "") c))
((deriveR r6 b c) z)
((deriveR r7 a c) (->re `(union (concatenation ,r2 ,r2) ,r2) c))
((deriveR r7 b c) z)
((deriveR r8 a c) (->re `(complement, r2) c))
((deriveR r8 b c) (->re `(complement ,z) c))
((deriveR r9 a c) r2)
((deriveR r9 b c) z)
((deriveR (->re `(repetition 1 2 "ab") c) a c)
(->re `(concatenation "b" (repetition 0 1 "ab")) c)))
;; An re-action is (cons re action)
;; derive : (list-of re-action) char cache -> (union (list-of re-action) #f)
;; applies deriveR to all the re-actions's re parts.
;; Returns #f if the derived state is equivalent to z.
(define (derive r c cache)
(let ((new-r (map (lambda (ra)
(cons (deriveR (car ra) c cache) (cdr ra)))
r)))
(if (andmap (lambda (x) (eq? z (car x)))
new-r)
#f
new-r)))
(test-block ((c (make-cache))
(r1 (->re #\1 c))
(r2 (->re #\2 c)))
((derive null (char->integer #\1) c) #f)
((derive (list (cons r1 1) (cons r2 2)) (char->integer #\1) c)
(list (cons e 1) (cons z 2)))
((derive (list (cons r1 1) (cons r2 2)) (char->integer #\3) c) #f))
;; get-final : (list-of re-action) -> (union #f syntax-object)
;; An re that accepts e represents a final state. Return the
;; action from the first final state or #f if there is none.
(define (get-final res)
(cond
((null? res) #f)
((re-nullable? (caar res)) (cdar res))
(else (get-final (cdr res)))))
(test-block ((c->i char->integer)
(c (make-cache))
(r1 (->re #\a c))
(r2 (->re #\b c))
(b (list (cons z 1) (cons z 2) (cons z 3) (cons e 4) (cons z 5)))
(a (list (cons r1 1) (cons r2 2))))
((derive null (c->i #\a) c) #f)
((derive a (c->i #\a) c) (list (cons e 1) (cons z 2)))
((derive a (c->i #\b) c) (list (cons z 1) (cons e 2)))
((derive a (c->i #\c) c) #f)
((derive (list (cons (->re `(union " " "\n" ",") c) 1)
(cons (->re `(concatenation (repetition 0 1 "-")
(repetition 1 +inf.0 (char-range "0" "9"))) c) 2)
(cons (->re `(concatenation "-" (repetition 1 +inf.0 "-")) c) 3)
(cons (->re "[" c) 4)
(cons (->re "]" c) 5)) (c->i #\[) c)
b)
((get-final a) #f)
((get-final (list (cons e 1) (cons e 2))) 1)
((get-final b) 4))
;; A state is (make-state (list-of re-action) nat)
(define-struct state (spec index))
;; get->key : re-action -> (list-of nat)
;; states are indexed by the list of indexes of their res
(define (get-key s)
(map (lambda (x) (re-index (car x))) s))
(define loc:partition is:partition)
;; compute-chars : (list-of state) -> (list-of char-set)
;; Computed the sets of equivalent characters for taking the
;; derivative of the car of st. Only one derivative per set need to be taken.
(define (compute-chars st)
(cond
((null? st) null)
(else
(loc:partition (map char-setR-chars
(apply append (map (lambda (x) (get-char-groups (car x) #f))
(state-spec (car st)))))))))
(test-block ((c (make-cache))
(c->i char->integer)
(r1 (->re `(char-range #\1 #\4) c))
(r2 (->re `(char-range #\2 #\3) c)))
((compute-chars null) null)
((compute-chars (list (make-state null 1))) null)
((map is:integer-set-contents
(compute-chars (list (make-state (list (cons r1 1) (cons r2 2)) 2))))
(list (is:integer-set-contents (is:make-range (c->i #\2) (c->i #\3)))
(is:integer-set-contents (is:union (is:make-range (c->i #\1))
(is:make-range (c->i #\4)))))))
;; A dfa is (make-dfa int int
;; (list-of (cons int syntax-object))
;; (list-of (cons int (list-of (cons char-set int)))))
;; Each transitions is a state and a list of chars with the state to transition to.
;; The finals and transitions are sorted by state number, and duplicate free.
(define-struct dfa (num-states start-state final-states/actions transitions) (make-inspector))
(define loc:get-integer is:get-integer)
;; build-dfa : (list-of re-action) cache -> dfa
(define (build-dfa rs cache)
(let* ((transitions (make-hash-table))
(get-state-number (make-counter))
(start (make-state rs (get-state-number))))
(cache (cons 'state (get-key rs)) (lambda () start))
(let loop ((old-states (list start))
(new-states null)
(all-states (list start))
(cs (compute-chars (list start))))
(cond
((and (null? old-states) (null? new-states))
(make-dfa (get-state-number) (state-index start)
(sort (filter (lambda (x) (cdr x))
(map (lambda (state)
(cons (state-index state) (get-final (state-spec state))))
all-states))
(lambda (a b) (< (car a) (car b))))
(sort (hash-table-map transitions
(lambda (state trans)
(cons (state-index state)
(map (lambda (t)
(cons (car t)
(state-index (cdr t))))
trans))))
(lambda (a b) (< (car a) (car b))))))
((null? old-states)
(loop new-states null all-states (compute-chars new-states)))
((null? cs)
(loop (cdr old-states) new-states all-states (compute-chars (cdr old-states))))
(else
(let* ((state (car old-states))
(c (car cs))
(new-re (derive (state-spec state) (loc:get-integer c) cache)))
(cond
(new-re
(let* ((new-state? #f)
(new-state (cache (cons 'state (get-key new-re))
(lambda ()
(set! new-state? #t)
(make-state new-re (get-state-number)))))
(new-all-states (if new-state? (cons new-state all-states) all-states)))
(hash-table-put! transitions
state
(cons (cons c new-state)
(hash-table-get transitions state
(lambda () null))))
(cond
(new-state?
(loop old-states (cons new-state new-states) new-all-states (cdr cs)))
(else
(loop old-states new-states new-all-states (cdr cs))))))
(else (loop old-states new-states all-states (cdr cs))))))))))
(define (print-dfa x)
(printf "number of states: ~a\n" (dfa-num-states x))
(printf "start state: ~a\n" (dfa-start-state x))
(printf "final states: ~a\n" (map car (dfa-final-states/actions x)))
(for-each (lambda (trans)
(printf "state: ~a\n" (car trans))
(for-each (lambda (rule)
(printf " -~a-> ~a\n"
(is:integer-set-contents (car rule))
(cdr rule)))
(cdr trans)))
(dfa-transitions x)))
(define (build-test-dfa rs)
(let ((c (make-cache)))
(build-dfa (map (lambda (x) (cons (->re x c) 'action))
rs)
c)))
#|
(define t1 (build-test-dfa null))
(define t2 (build-test-dfa `(#\a)))
(define t3 (build-test-dfa `(#\a #\b)))
(define t4 (build-test-dfa `((repetition 0 +inf.0 #\a)
(repetition 0 +inf.0 (concatenation #\a #\b)))))
(define t5 (build-test-dfa `((concatenation (repetition 0 +inf.0 (union #\0 #\1)) #\1))))
(define t6 (build-test-dfa `((repetition 0 +inf.0 (repetition 0 +inf.0 #\a))
(repetition 0 +inf.0 (concatenation #\b (repetition 1 +inf.0 #\b))))))
(define t7 (build-test-dfa `((concatenation (repetition 0 +inf.0 #\a) (repetition 0 +inf.0 #\b)
(repetition 0 +inf.0 #\c) (repetition 0 +inf.0 #\d)
(repetition 0 +inf.0 #\e)))))
(define t8
(build-test-dfa `((concatenation (repetition 0 +inf.0 (union #\a #\b)) #\a (union #\a #\b)
(union #\a #\b) (union #\a #\b) (union #\a #\b)))))
(define t9 (build-test-dfa `((concatenation "/*"
(complement (concatenation (intersection) "*/" (intersection)))
"*/"))))
(define t11 (build-test-dfa `((complement "1"))))
(define t12 (build-test-dfa `((concatenation (intersection (concatenation (repetition 0 +inf.0 "a") "b")
(concatenation "a" (repetition 0 +inf.0 "b")))
"ab"))))
(define x (build-test-dfa `((union " " "\n" ",")
(concatenation (repetition 0 1 "-") (repetition 1 +inf.0 (char-range "0" "9")))
(concatenation "-" (repetition 1 +inf.0 "-"))
"["
"]")))
(define y (build-test-dfa
`((repetition 1 +inf.0
(union (concatenation "|" (repetition 0 +inf.0 (char-complement "|")) "|")
(concatenation "|" (repetition 0 +inf.0 (char-complement "|"))))))))
(define t13 (build-test-dfa `((intersection (concatenation (intersection) "111" (intersection))
(complement (union (concatenation (intersection) "01")
(repetition 1 +inf.0 "1")))))))
(define t14 (build-test-dfa `((complement "1"))))
|#
)

4
br-parser-tools-lib/br-parser-tools/private-lex/error-tests.rkt → parser-tools-lib/parser-tools/private-lex/error-tests.rkt
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@ -1,5 +1,5 @@
#lang racket/base
(require (for-syntax racket/base)
#lang scheme/base
(require (for-syntax scheme/base)
"../lex.rkt"
rackunit)

179
parser-tools-lib/parser-tools/private-lex/front.rkt
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(module front mzscheme
(require (prefix is: mzlib/integer-set)
mzlib/list
syntax/stx
"util.rkt"
"stx.rkt"
"re.rkt"
"deriv.rkt")
(provide build-lexer)
(define-syntax time-label
(syntax-rules ()
((_ l e ...)
(begin
(printf "~a: " l)
(time (begin e ...))))))
;; A table is either
;; - (vector-of (union #f nat))
;; - (vector-of (vector-of (vector nat nat nat)))
(define loc:integer-set-contents is:integer-set-contents)
;; dfa->1d-table : dfa -> (same as build-lexer)
(define (dfa->1d-table dfa)
(let ((state-table (make-vector (dfa-num-states dfa) #f))
(transition-cache (make-hash-table 'equal)))
(for-each
(lambda (trans)
(let* ((from-state (car trans))
(all-chars/to (cdr trans))
(flat-all-chars/to
(sort
(apply append
(map (lambda (chars/to)
(let ((char-ranges (loc:integer-set-contents (car chars/to)))
(to (cdr chars/to)))
(map (lambda (char-range)
(let ((entry (vector (car char-range) (cdr char-range) to)))
(hash-table-get transition-cache entry
(lambda ()
(hash-table-put! transition-cache
entry
entry)
entry))))
char-ranges)))
all-chars/to))
(lambda (a b)
(< (vector-ref a 0) (vector-ref b 0))))))
(vector-set! state-table from-state (list->vector flat-all-chars/to))))
(dfa-transitions dfa))
state-table))
(define loc:foldr is:foldr)
;; dfa->2d-table : dfa -> (same as build-lexer)
(define (dfa->2d-table dfa)
(let (
;; char-table : (vector-of (union #f nat))
;; The lexer table, one entry per state per char.
;; Each entry specifies a state to transition to.
;; #f indicates no transition
(char-table (make-vector (* 256 (dfa-num-states dfa)) #f)))
;; Fill the char-table vector
(for-each
(lambda (trans)
(let ((from-state (car trans)))
(for-each (lambda (chars/to)
(let ((to-state (cdr chars/to)))
(loc:foldr (lambda (char _)
(vector-set! char-table
(bitwise-ior
char
(arithmetic-shift from-state 8))
to-state))
(void)
(car chars/to))))
(cdr trans))))
(dfa-transitions dfa))
char-table))
;; dfa->actions : dfa -> (vector-of (union #f syntax-object))
;; The action for each final state, #f if the state isn't final
(define (dfa->actions dfa)
(let ((actions (make-vector (dfa-num-states dfa) #f)))
(for-each (lambda (state/action)
(vector-set! actions (car state/action) (cdr state/action)))
(dfa-final-states/actions dfa))
actions))
;; dfa->no-look : dfa -> (vector-of bool)
;; For each state whether the lexer can ignore the next input.
;; It can do this only if there are no transitions out of the
;; current state.
(define (dfa->no-look dfa)
(let ((no-look (make-vector (dfa-num-states dfa) #t)))
(for-each (lambda (trans)
(vector-set! no-look (car trans) #f))
(dfa-transitions dfa))
no-look))
(test-block ((d1 (make-dfa 1 1 (list) (list)))
(d2 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3))))))
(d3 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 100 200) 0)
(cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3)))))))
((dfa->2d-table d1) (make-vector 256 #f))
((dfa->2d-table d2) (let ((v (make-vector 1024 #f)))
(vector-set! v 305 1)
(vector-set! v 306 1)
(vector-set! v 307 2)
(vector-set! v 561 3)
v))
((dfa->1d-table d1) (make-vector 1 #f))
((dfa->1d-table d2) #(#f
#(#(49 50 1) #(51 51 2))
#(#(49 49 3))
#f))
((dfa->1d-table d3) #(#f
#(#(49 50 1) #(51 51 2) #(100 200 0))
#(#(49 49 3))
#f))
((dfa->actions d1) (vector #f))
((dfa->actions d2) (vector #f #f 2 3))
((dfa->no-look d1) (vector #t))
((dfa->no-look d2) (vector #t #f #f #t)))
;; build-lexer : syntax-object list ->
;; (values table nat (vector-of (union #f syntax-object)) (vector-of bool) (list-of syntax-object))
;; each syntax object has the form (re action)
(define (build-lexer sos)
(let* ((disappeared-uses (box null))
(s-re-acts (map (lambda (so)
(cons (parse (stx-car so) disappeared-uses)
(stx-car (stx-cdr so))))
sos))
(cache (make-cache))
(re-acts (map (lambda (s-re-act)
(cons (->re (car s-re-act) cache)
(cdr s-re-act)))
s-re-acts))
(dfa (build-dfa re-acts cache))
(table (dfa->1d-table dfa)))
;(print-dfa dfa)
#;(let ((num-states (vector-length table))
(num-vectors (length (filter values (vector->list table))))
(num-entries (apply + (map
(lambda (x) (if x (vector-length x) 0))
(vector->list table))))
(num-different-entries
(let ((ht (make-hash-table)))
(for-each
(lambda (x)
(when x
(for-each
(lambda (y)
(hash-table-put! ht y #t))
(vector->list x))))
(vector->list table))
(length (hash-table-map ht cons)))))
(printf "~a states, ~aKB\n"
num-states
(/ (* 4.0 (+ 2 num-states (* 2 num-vectors) num-entries
(* 5 num-different-entries))) 1024)))
(values table (dfa-start-state dfa) (dfa->actions dfa) (dfa->no-look dfa)
(unbox disappeared-uses))))
)

385
parser-tools-lib/parser-tools/private-lex/re.rkt
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(module re mzscheme
(require mzlib/list
scheme/match
(prefix is: mzlib/integer-set)
"util.rkt")
(provide ->re build-epsilon build-zero build-char-set build-concat
build-repeat build-or build-and build-neg
epsilonR? zeroR? char-setR? concatR? repeatR? orR? andR? negR?
char-setR-chars concatR-re1 concatR-re2 repeatR-re repeatR-low repeatR-high
orR-res andR-res negR-re
re-nullable? re-index)
;; get-index : -> nat
(define get-index (make-counter))
;; An re is either
;; - (make-epsilonR bool nat)
;; - (make-zeroR bool nat)
;; - (make-char-setR bool nat char-set)
;; - (make-concatR bool nat re re)
;; - (make-repeatR bool nat nat nat-or-+inf.0 re)
;; - (make-orR bool nat (list-of re)) Must not directly contain any orRs
;; - (make-andR bool nat (list-of re)) Must not directly contain any andRs
;; - (make-negR bool nat re)
;;
;; Every re must have an index field globally different from all
;; other re index fields.
(define-struct re (nullable? index) (make-inspector))
(define-struct (epsilonR re) () (make-inspector))
(define-struct (zeroR re) () (make-inspector))
(define-struct (char-setR re) (chars) (make-inspector))
(define-struct (concatR re) (re1 re2) (make-inspector))
(define-struct (repeatR re) (low high re) (make-inspector))
(define-struct (orR re) (res) (make-inspector))
(define-struct (andR re) (res) (make-inspector))
(define-struct (negR re) (re) (make-inspector))
;; e : re
;; The unique epsilon re
(define e (make-epsilonR #t (get-index)))
;; z : re
;; The unique zero re
(define z (make-zeroR #f (get-index)))
;; s-re = char constant
;; | string constant (sequence of characters)
;; | re a precompiled re
;; | (repetition low high s-re) repetition between low and high times (inclusive)
;; | (union s-re ...)
;; | (intersection s-re ...)
;; | (complement s-re)
;; | (concatenation s-re ...)
;; | (char-range rng rng) match any character between two (inclusive)
;; | (char-complement char-set) match any character not listed
;; low = natural-number
;; high = natural-number or +inf.0
;; rng = char or string with length 1
;; (concatenation) (repetition 0 0 x), and "" match the empty string.
;; (union) matches no strings.
;; (intersection) matches any string.
(define loc:make-range is:make-range)
(define loc:union is:union)
(define loc:split is:split)
(define loc:complement is:complement)
;; ->re : s-re cache -> re
(define (->re exp cache)
(match exp
((? char?) (build-char-set (loc:make-range (char->integer exp)) cache))
((? string?) (->re `(concatenation ,@(string->list exp)) cache))
((? re?) exp)
(`(repetition ,low ,high ,r)
(build-repeat low high (->re r cache) cache))
(`(union ,rs ...)
(build-or (flatten-res (map (lambda (r) (->re r cache)) rs)
orR? orR-res loc:union cache)
cache))
(`(intersection ,rs ...)
(build-and (flatten-res (map (lambda (r) (->re r cache)) rs)
andR? andR-res (lambda (a b)
(let-values (((i _ __) (loc:split a b))) i))
cache)
cache))
(`(complement ,r)
(build-neg (->re r cache) cache))
(`(concatenation ,rs ...)
(foldr (lambda (x y)
(build-concat (->re x cache) y cache))
e
rs))
(`(char-range ,c1 ,c2)
(let ((i1 (char->integer (if (string? c1) (string-ref c1 0) c1)))
(i2 (char->integer (if (string? c2) (string-ref c2 0) c2))))
(if (<= i1 i2)
(build-char-set (loc:make-range i1 i2) cache)
z)))
(`(char-complement ,crs ...)
(let ((cs (->re `(union ,@crs) cache)))
(cond
((zeroR? cs) (build-char-set (loc:make-range 0 max-char-num) cache))
((char-setR? cs)
(build-char-set (loc:complement (char-setR-chars cs) 0 max-char-num) cache))
(else z))))))
;; flatten-res: (list-of re) (re -> bool) (re -> (list-of re))
;; (char-set char-set -> char-set) cache -> (list-of re)
;; Takes all the char-sets in l and combines them into one char-set using the combine function.
;; Flattens out the values of type?. get-res only needs to function on things type? returns
;; true for.
(define (flatten-res l type? get-res combine cache)
(let loop ((res l)
;; chars : (union #f char-set)
(chars #f)
(no-chars null))
(cond
((null? res)
(if chars
(cons (build-char-set chars cache) no-chars)
no-chars))
((char-setR? (car res))
(if chars
(loop (cdr res) (combine (char-setR-chars (car res)) chars) no-chars)
(loop (cdr res) (char-setR-chars (car res)) no-chars)))
((type? (car res))
(loop (append (get-res (car res)) (cdr res)) chars no-chars))
(else (loop (cdr res) chars (cons (car res) no-chars))))))
;; build-epsilon : -> re
(define (build-epsilon) e)
(define (build-zero) z)
(define loc:integer-set-contents is:integer-set-contents)
;; build-char-set : char-set cache -> re
(define (build-char-set cs cache)
(let ((l (loc:integer-set-contents cs)))
(cond
((null? l) z)
(else
(cache l
(lambda ()
(make-char-setR #f (get-index) cs)))))))
;; build-concat : re re cache -> re
(define (build-concat r1 r2 cache)
(cond
((eq? e r1) r2)
((eq? e r2) r1)
((or (eq? z r1) (eq? z r2)) z)
(else
(cache (cons 'concat (cons (re-index r1) (re-index r2)))
(lambda ()
(make-concatR (and (re-nullable? r1) (re-nullable? r2))
(get-index)
r1 r2))))))
;; build-repeat : nat nat-or-+inf.0 re cache -> re
(define (build-repeat low high r cache)
(let ((low (if (< low 0) 0 low)))
(cond
((eq? r e) e)
((and (= 0 low) (or (= 0 high) (eq? z r))) e)
((and (= 1 low) (= 1 high)) r)
((and (repeatR? r)
(eq? (repeatR-high r) +inf.0)
(or (= 0 (repeatR-low r))
(= 1 (repeatR-low r))))
(build-repeat (* low (repeatR-low r))
+inf.0
(repeatR-re r)
cache))
(else
(cache (cons 'repeat (cons low (cons high (re-index r))))
(lambda ()
(make-repeatR (or (re-nullable? r) (= 0 low)) (get-index) low high r)))))))
;; build-or : (list-of re) cache -> re
(define (build-or rs cache)
(let ((rs
(filter
(lambda (x) (not (eq? x z)))
(do-simple-equiv (replace rs orR? orR-res null) re-index))))
(cond
((null? rs) z)
((null? (cdr rs)) (car rs))
((memq (build-neg z cache) rs) (build-neg z cache))
(else
(cache (cons 'or (map re-index rs))
(lambda ()
(make-orR (ormap re-nullable? rs) (get-index) rs)))))))
;; build-and : (list-of re) cache -> re
(define (build-and rs cache)
(let ((rs (do-simple-equiv (replace rs andR? andR-res null) re-index)))
(cond
((null? rs) (build-neg z cache))
((null? (cdr rs)) (car rs))
((memq z rs) z)
(else
(cache (cons 'and (map re-index rs))
(lambda ()
(make-andR (andmap re-nullable? rs) (get-index) rs)))))))
;; build-neg : re cache -> re
(define (build-neg r cache)
(cond
((negR? r) (negR-re r))
(else
(cache (cons 'neg (re-index r))
(lambda ()
(make-negR (not (re-nullable? r)) (get-index) r))))))
;; Tests for the build-functions
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r1 (build-char-set (is:make-range (char->integer #\1)) c))
(r2 (build-char-set (is:make-range (char->integer #\2)) c))
(r3 (build-char-set (is:make-range (char->integer #\3)) c))
(rc (build-concat r1 r2 c))
(rc2 (build-concat r2 r1 c))
(rr (build-repeat 0 +inf.0 rc c))
(ro (build-or `(,rr ,rc ,rr) c))
(ro2 (build-or `(,rc ,rr ,z) c))
(ro3 (build-or `(,rr ,rc) c))
(ro4 (build-or `(,(build-or `(,r1 ,r2) c)
,(build-or `(,r2 ,r3) c)) c))
(ra (build-and `(,rr ,rc ,rr) c))
(ra2 (build-and `(,rc ,rr) c))
(ra3 (build-and `(,rr ,rc) c))
(ra4 (build-and `(,(build-and `(,r3 ,r2) c)
,(build-and `(,r2 ,r1) c)) c))
(rn (build-neg z c))
(rn2 (build-neg r1 c)))
((isc (char-setR-chars r1)) (isc (is:make-range (char->integer #\1))))
((isc (char-setR-chars r2)) (isc (is:make-range (char->integer #\2))))
((isc (char-setR-chars r3)) (isc (is:make-range (char->integer #\3))))
((build-char-set (is:make-range) c) z)
((build-concat r1 e c) r1)
((build-concat e r1 c) r1)
((build-concat r1 z c) z)
((build-concat z r1 c) z)
((build-concat r1 r2 c) rc)
((concatR-re1 rc) r1)
((concatR-re2 rc) r2)
((concatR-re1 rc2) r2)
((concatR-re2 rc2) r1)
(ro ro2)
(ro ro3)
(ro4 (build-or `(,r1 ,r2 ,r3) c))
((orR-res ro) (list rc rr))
((orR-res ro4) (list r1 r2 r3))
((build-or null c) z)
((build-or `(,r1 ,z) c) r1)
((build-repeat 0 +inf.0 rc c) rr)
((build-repeat 0 1 z c) e)
((build-repeat 0 0 rc c) e)
((build-repeat 0 +inf.0 z c) e)
((build-repeat -1 +inf.0 z c) e)
((build-repeat 0 +inf.0 (build-repeat 0 +inf.0 rc c) c)
(build-repeat 0 +inf.0 rc c))
((build-repeat 20 20 (build-repeat 0 +inf.0 rc c) c)
(build-repeat 0 +inf.0 rc c))
((build-repeat 20 20 (build-repeat 1 +inf.0 rc c) c)
(build-repeat 20 +inf.0 rc c))
((build-repeat 1 1 rc c) rc)
((repeatR-re rr) rc)
(ra ra2)
(ra ra3)
(ra4 (build-and `(,r1 ,r2 ,r3) c))
((andR-res ra) (list rc rr))
((andR-res ra4) (list r1 r2 r3))
((build-and null c) (build-neg z c))
((build-and `(,r1 ,z) c) z)
((build-and `(,r1) c) r1)
((build-neg r1 c) (build-neg r1 c))
((build-neg (build-neg r1 c) c) r1)
((negR-re (build-neg r2 c)) r2)
((re-nullable? r1) #f)
((re-nullable? rc) #f)
((re-nullable? (build-concat rr rr c)) #t)
((re-nullable? rr) #t)
((re-nullable? (build-repeat 0 1 rc c)) #t)
((re-nullable? (build-repeat 1 2 rc c)) #f)
((re-nullable? (build-repeat 1 2 (build-or (list e r1) c) c)) #t)
((re-nullable? ro) #t)
((re-nullable? (build-or `(,r1 ,r2) c)) #f)
((re-nullable? (build-and `(,r1 ,e) c)) #f)
((re-nullable? (build-and `(,rr ,e) c)) #t)
((re-nullable? (build-neg r1 c)) #t)
((re-nullable? (build-neg rr c)) #f))
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r1 (->re #\1 c))
(r2 (->re #\2 c))
(r3-5 (->re '(char-range #\3 #\5) c))
(r4 (build-or `(,r1 ,r2) c))
(r5 (->re `(union ,r3-5 #\7) c))
(r6 (->re #\6 c)))
((flatten-res null orR? orR-res is:union c) null)
((isc (char-setR-chars (car (flatten-res `(,r1) orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1))))
((isc (char-setR-chars (car (flatten-res `(,r4) orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1) (char->integer #\2))))
((isc (char-setR-chars (car (flatten-res `(,r6 ,r5 ,r4 ,r3-5 ,r2 ,r1)
orR? orR-res is:union c))))
(isc (is:make-range (char->integer #\1) (char->integer #\7))))
((flatten-res `(,r1 ,r2) andR? andR-res (lambda (x y)
(let-values (((i _ __)
(is:split x y)))
i))
c)
(list z)))
;; ->re
(test-block ((c (make-cache))
(isc is:integer-set-contents)
(r (->re #\a c))
(rr (->re `(concatenation ,r ,r) c))
(rrr (->re `(concatenation ,r ,rr) c))
(rrr* (->re `(repetition 0 +inf.0 ,rrr) c)))
((isc (char-setR-chars r)) (isc (is:make-range (char->integer #\a))))
((->re "" c) e)
((->re "asdf" c) (->re `(concatenation #\a #\s #\d #\f) c))
((->re r c) r)
((->re `(repetition 0 +inf.0 ,r) c) (build-repeat 0 +inf.0 r c))
((->re `(repetition 1 +inf.0 ,r) c) (build-repeat 1 +inf.0 r c))
((->re `(repetition 0 1 ,r) c) (build-repeat 0 1 r c))
((->re `(repetition 0 1 ,rrr*) c) rrr*)
((->re `(union (union (char-range #\a #\c)
(char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(union (repetition 0 +inf.0 #\2))) c)
(build-or (list (build-char-set (is:union (is:make-range 73)
(is:make-range 97 99))
c)
(build-repeat 0 +inf.0 (build-char-set (is:make-range 50) c) c))
c))
((->re `(union ,rr ,rrr) c) (build-or (list rr rrr) c))
((->re `(union ,r) c) r)
((->re `(union) c) z)
((->re `(intersection (intersection #\111
(char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(intersection (repetition 0 +inf.0 #\2))) c)
(build-and (list (build-char-set (is:make-range 73) c)
(build-repeat 0 +inf.0 (build-char-set (is:make-range 50) c) c))
c))
((->re `(intersection (intersection #\000 (char-complement (char-range #\000 #\110)
(char-range #\112 ,(integer->char max-char-num))))
(intersection (repetition 0 +inf.0 #\2))) c)
z)
((->re `(intersection ,rr ,rrr) c) (build-and (list rr rrr) c))
((->re `(intersection ,r) c) r)
((->re `(intersection) c) (build-neg z c))
((->re `(complement ,r) c) (build-neg r c))
((->re `(concatenation) c) e)
((->re `(concatenation ,rrr*) c) rrr*)
(rr (build-concat r r c))
((->re `(concatenation ,r ,rr ,rrr) c)
(build-concat r (build-concat rr rrr c) c))
((isc (char-setR-chars (->re `(char-range #\1 #\1) c))) (isc (is:make-range 49)))
((isc (char-setR-chars (->re `(char-range #\1 #\9) c))) (isc (is:make-range 49 57)))
((isc (char-setR-chars (->re `(char-range "1" "1") c))) (isc (is:make-range 49)))
((isc (char-setR-chars (->re `(char-range "1" "9") c))) (isc (is:make-range 49 57)))
((->re `(char-range "9" "1") c) z)
((isc (char-setR-chars (->re `(char-complement) c)))
(isc (char-setR-chars (->re `(char-range #\000 ,(integer->char max-char-num)) c))))
((isc (char-setR-chars (->re `(char-complement #\001 (char-range #\002 ,(integer->char max-char-num))) c)))
(isc (is:make-range 0)))
)
)

220
parser-tools-lib/parser-tools/private-lex/stx.rkt
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@ -0,0 +1,220 @@
#lang racket
(require "util.rkt"
syntax/id-table)
(provide parse)
(define (bad-args stx num)
(raise-syntax-error
#f
(format "incorrect number of arguments (should have ~a)" num)
stx))
;; char-range-arg: syntax-object syntax-object -> nat
;; If c contains is a character or length 1 string, returns the integer
;; for the character. Otherwise raises a syntax error.
(define (char-range-arg stx containing-stx)
(let ((c (syntax-e stx)))
(cond
((char? c) (char->integer c))
((and (string? c) (= (string-length c) 1))
(char->integer (string-ref c 0)))
(else
(raise-syntax-error
#f
"not a char or single-char string"
containing-stx stx)))))
(module+ test
(check-equal? (char-range-arg #'#\1 #'here) (char->integer #\1))
(check-equal? (char-range-arg #'"1" #'here) (char->integer #\1)))
(define orig-insp (variable-reference->module-declaration-inspector
(#%variable-reference)))
(define (disarm stx)
(syntax-disarm stx orig-insp))
;; parse : syntax-object (box (list-of syntax-object)) -> s-re (see re.rkt)
;; checks for errors and generates the plain s-exp form for s
;; Expands lex-abbrevs and applies lex-trans.
(define (parse stx disappeared-uses)
(let loop ([stx stx]
[disappeared-uses disappeared-uses]
;; seen-lex-abbrevs: id-table
[seen-lex-abbrevs (make-immutable-free-id-table)])
(let ([recur (lambda (s)
(loop (syntax-rearm s stx)
disappeared-uses
seen-lex-abbrevs))]
[recur/abbrev (lambda (s id)
(loop (syntax-rearm s stx)
disappeared-uses
(free-id-table-set seen-lex-abbrevs id id)))])
(syntax-case (disarm stx) (repetition union intersection complement concatenation
char-range char-complement)
(_
(identifier? stx)
(let ((expansion (syntax-local-value stx (lambda () #f))))
(unless (lex-abbrev? expansion)
(raise-syntax-error 'regular-expression
"undefined abbreviation"
stx))
;; Check for cycles.
(when (free-id-table-ref seen-lex-abbrevs stx (lambda () #f))
(raise-syntax-error 'regular-expression
"illegal lex-abbrev cycle detected"
stx
#f
(list (free-id-table-ref seen-lex-abbrevs stx))))
(set-box! disappeared-uses (cons stx (unbox disappeared-uses)))
(recur/abbrev ((lex-abbrev-get-abbrev expansion)) stx)))
(_
(or (char? (syntax-e stx)) (string? (syntax-e stx)))
(syntax-e stx))
((repetition arg ...)
(let ((arg-list (syntax->list (syntax (arg ...)))))
(unless (= 3 (length arg-list))
(bad-args stx 2))
(let ((low (syntax-e (car arg-list)))
(high (syntax-e (cadr arg-list)))
(re (caddr arg-list)))
(unless (and (number? low) (exact? low) (integer? low) (>= low 0))
(raise-syntax-error #f
"not a non-negative exact integer"
stx
(car arg-list)))
(unless (or (and (number? high) (exact? high) (integer? high) (>= high 0))
(eq? high +inf.0))
(raise-syntax-error #f
"not a non-negative exact integer or +inf.0"
stx
(cadr arg-list)))
(unless (<= low high)
(raise-syntax-error
#f
"the first argument is not less than or equal to the second argument"
stx))
`(repetition ,low ,high ,(recur re)))))
((union re ...)
`(union ,@(map recur (syntax->list (syntax (re ...))))))
((intersection re ...)
`(intersection ,@(map recur (syntax->list (syntax (re ...))))))
((complement re ...)
(let ((re-list (syntax->list (syntax (re ...)))))
(unless (= 1 (length re-list))
(bad-args stx 1))
`(complement ,(recur (car re-list)))))
((concatenation re ...)
`(concatenation ,@(map recur (syntax->list (syntax (re ...))))))
((char-range arg ...)
(let ((arg-list (syntax->list (syntax (arg ...)))))
(unless (= 2 (length arg-list))
(bad-args stx 2))
(let ((i1 (char-range-arg (car arg-list) stx))
(i2 (char-range-arg (cadr arg-list) stx)))
(if (<= i1 i2)
`(char-range ,(integer->char i1) ,(integer->char i2))
(raise-syntax-error
#f
"the first argument does not precede or equal second argument"
stx)))))
((char-complement arg ...)
(let ((arg-list (syntax->list (syntax (arg ...)))))
(unless (= 1 (length arg-list))
(bad-args stx 1))
(let ((parsed (recur (car arg-list))))
(unless (char-set? parsed)
(raise-syntax-error #f
"not a character set"
stx
(car arg-list)))
`(char-complement ,parsed))))
((op form ...)
(identifier? (syntax op))
(let* ((o (syntax op))
(expansion (syntax-local-value o (lambda () #f))))
(set-box! disappeared-uses (cons o (unbox disappeared-uses)))
(cond
((lex-trans? expansion)
(recur ((lex-trans-f expansion) (disarm stx))))
(expansion
(raise-syntax-error 'regular-expression
"not a lex-trans"
stx))
(else
(raise-syntax-error 'regular-expression
"undefined operator"
stx)))))
(_
(raise-syntax-error
'regular-expression
"not a char, string, identifier, or (op args ...)"
stx))))))
;; char-set? : s-re -> bool
;; A char-set is an re that matches only strings of length 1.
;; char-set? is conservative.
(define (char-set? s-re)
(cond
((char? s-re) #t)
((string? s-re) (= (string-length s-re) 1))
((list? s-re)
(let ((op (car s-re)))
(case op
((union intersection) (andmap char-set? (cdr s-re)))
((char-range char-complement) #t)
((repetition)
(and (= (cadr s-re) (caddr s-re)) (char-set? (cadddr s-re))))
((concatenation)
(and (= 2 (length s-re)) (char-set? (cadr s-re))))
(else #f))))
(else #f)))
(module+ test
(require rackunit))
(module+ test
(check-equal? (char-set? #\a) #t)
(check-equal? (char-set? "12") #f)
(check-equal? (char-set? "1") #t)
(check-equal? (char-set? '(repetition 1 2 #\1)) #f)
(check-equal? (char-set? '(repetition 1 1 "12")) #f)
(check-equal? (char-set? '(repetition 1 1 "1")) #t)
(check-equal? (char-set? '(union "1" "2" "3")) #t)
(check-equal? (char-set? '(union "1" "" "3")) #f)
(check-equal? (char-set? '(intersection "1" "2" (union "3" "4"))) #t)
(check-equal? (char-set? '(intersection "1" "")) #f)
(check-equal? (char-set? '(complement "1")) #f)
(check-equal? (char-set? '(concatenation "1" "2")) #f)
(check-equal? (char-set? '(concatenation "" "2")) #f)
(check-equal? (char-set? '(concatenation "1")) #t)
(check-equal? (char-set? '(concatenation "12")) #f)
(check-equal? (char-set? '(char-range #\1 #\2)) #t)
(check-equal? (char-set? '(char-complement #\1)) #t))
;; yikes... these test cases all have the wrong arity, now.
;; and by "now", I mean it's been broken since before we
;; moved to git.
(module+ test
(check-equal? (parse #'#\a null) #\a)
(check-equal? (parse #'"1" null) "1")
(check-equal? (parse #'(repetition 1 1 #\1) null)
'(repetition 1 1 #\1))
(check-equal? (parse #'(repetition 0 +inf.0 #\1) null) '(repetition 0 +inf.0 #\1))
(check-equal? (parse #'(union #\1 (union "2") (union)) null)
'(union #\1 (union "2") (union)))
(check-equal? (parse #'(intersection #\1 (intersection "2") (intersection))
null)
'(intersection #\1 (intersection "2") (intersection)))
(check-equal? (parse #'(complement (union #\1 #\2))
null)
'(complement (union #\1 #\2)))
(check-equal? (parse #'(concatenation "1" "2" (concatenation)) null)
'(concatenation "1" "2" (concatenation)))
(check-equal? (parse #'(char-range "1" #\1) null) '(char-range #\1 #\1))
(check-equal? (parse #'(char-range #\1 "1") null) '(char-range #\1 #\1))
(check-equal? (parse #'(char-range "1" "3") null) '(char-range #\1 #\3))
(check-equal? (parse #'(char-complement (union "1" "2")) null)
'(char-complement (union "1" "2"))))
; )

9
parser-tools-lib/parser-tools/private-lex/token-syntax.rkt
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@ -0,0 +1,9 @@
(module token-syntax mzscheme
;; The things needed at compile time to handle definition of tokens
(provide make-terminals-def terminals-def-t terminals-def?
make-e-terminals-def e-terminals-def-t e-terminals-def?)
(define-struct terminals-def (t))
(define-struct e-terminals-def (t))
)

89
parser-tools-lib/parser-tools/private-lex/token.rkt
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@ -0,0 +1,89 @@
(module token mzscheme
(require-for-syntax "token-syntax.rkt")
;; Defining tokens
(provide define-tokens define-empty-tokens make-token token?
(protect (rename token-name real-token-name))
(protect (rename token-value real-token-value))
(rename token-name* token-name)
(rename token-value* token-value)
(struct position (offset line col))
(struct position-token (token start-pos end-pos)))
;; A token is either
;; - symbol
;; - (make-token symbol any)
(define-struct token (name value) (make-inspector))
;; token-name*: token -> symbol
(define (token-name* t)
(cond
((symbol? t) t)
((token? t) (token-name t))
(else (raise-type-error
'token-name
"symbol or struct:token"
0
t))))
;; token-value*: token -> any
(define (token-value* t)
(cond
((symbol? t) #f)
((token? t) (token-value t))
(else (raise-type-error
'token-value
"symbol or struct:token"
0
t))))
(define-for-syntax (make-ctor-name n)
(datum->syntax-object n
(string->symbol (format "token-~a" (syntax-e n)))
n
n))
(define-for-syntax (make-define-tokens empty?)
(lambda (stx)
(syntax-case stx ()
((_ name (token ...))
(andmap identifier? (syntax->list (syntax (token ...))))
(with-syntax (((marked-token ...)
(map values #;(make-syntax-introducer)
(syntax->list (syntax (token ...))))))
(quasisyntax/loc stx
(begin
(define-syntax name
#,(if empty?
#'(make-e-terminals-def (quote-syntax (marked-token ...)))
#'(make-terminals-def (quote-syntax (marked-token ...)))))
#,@(map
(lambda (n)
(when (eq? (syntax-e n) 'error)
(raise-syntax-error
#f
"Cannot define a token named error."
stx))
(if empty?
#`(define (#,(make-ctor-name n))
'#,n)
#`(define (#,(make-ctor-name n) x)
(make-token '#,n x))))
(syntax->list (syntax (token ...))))
#;(define marked-token #f) #;...))))
((_ ...)
(raise-syntax-error
#f
"must have the form (define-tokens name (identifier ...)) or (define-empty-tokens name (identifier ...))"
stx)))))
(define-syntax define-tokens (make-define-tokens #f))
(define-syntax define-empty-tokens (make-define-tokens #t))
(define-struct position (offset line col) #f)
(define-struct position-token (token start-pos end-pos) #f)
)

50
br-parser-tools-lib/br-parser-tools/private-lex/unicode-chars.rkt → parser-tools-lib/parser-tools/private-lex/unicode-chars.rkt
Unescape Escape View File

@ -1,5 +1,6 @@
#lang racket/base
(require racket/promise "util.rkt")
#lang racket
(require "util.rkt")
(provide (all-defined-out))
@ -9,33 +10,36 @@
;; get-chars-for-x : (nat -> bool) (listof (list nat nat bool)) -> (listof (cons nat nat))
(define (get-chars-for char-x? mapped-chars)
(cond
[(null? mapped-chars) null]
[else
(define range (car mapped-chars))
(define low (car range))
(define high (cadr range))
(define x (char-x? low))
((null? mapped-chars) null)
(else
(let* ((range (car mapped-chars))
(low (car range))
(high (cadr range))
(x (char-x? low)))
(cond
[(caddr range)
((caddr range)
(if x
(cons (cons low high) (get-chars-for char-x? (cdr mapped-chars)))
(get-chars-for char-x? (cdr mapped-chars)))]
[else
(let loop ([range-start low]
[i (car range)]
[parity x])
(cons (cons low high)
(get-chars-for char-x? (cdr mapped-chars)))
(get-chars-for char-x? (cdr mapped-chars))))
(else
(let loop ((range-start low)
(i (car range))
(parity x))
(cond
[(> i high)
((> i high)
(if parity
(cons (cons range-start high) (get-chars-for char-x? (cdr mapped-chars)))
(get-chars-for char-x? (cdr mapped-chars)))]
[(eq? parity (char-x? i))
(loop range-start (add1 i) parity)]
[parity (cons (cons range-start (sub1 i)) (loop i (add1 i) #f))]
[else (loop i (add1 i) #t)]))])]))
(get-chars-for char-x? (cdr mapped-chars))))
((eq? parity (char-x? i))
(loop range-start (add1 i) parity))
(parity
(cons (cons range-start (sub1 i)) (loop i (add1 i) #f)))
(else
(loop i (add1 i) #t))))))))))
(define (compute-ranges x?)
(delay (get-chars-for (λ (x) (x? (integer->char x))) mapped-chars)))
(delay (get-chars-for (lambda (x) (x? (integer->char x))) mapped-chars)))
(define alphabetic-ranges (compute-ranges char-alphabetic?)) ;; 325
(define lower-case-ranges (compute-ranges char-lower-case?)) ;; 405
@ -57,7 +61,7 @@
(check-equal? (get-chars-for odd? '()) '())
(check-equal? (get-chars-for odd? '((1 4 #f) (8 13 #f)))
'((1 . 1) (3 . 3) (9 . 9) (11 . 11) (13 . 13)))
(check-equal? (get-chars-for (λ (x)
(check-equal? (get-chars-for (lambda (x)
(odd? (quotient x 10)))
'((1 5 #t) (17 19 #t) (21 51 #f)))
'((17 . 19) (30 . 39) (50 . 51))))

70
br-parser-tools-lib/br-parser-tools/private-lex/util.rkt → parser-tools-lib/parser-tools/private-lex/util.rkt
Unescape Escape View File

@ -1,5 +1,4 @@
#lang racket/base
(require (for-syntax racket/base))
#lang racket
(provide (all-defined-out))
@ -11,16 +10,16 @@
(module+ test
(require rackunit))
(define-syntax (test-block stx)
(syntax-case stx ()
[(_ defs (code right-ans) ...)
#'(module+ test
(require rackunit)
#;(define-syntax test-block
(syntax-rules ()
((_ defs (code right-ans) ...)
(let* defs
(let ([real-ans code])
(check-equal? real-ans right-ans)) ...))]))
(let ((real-ans code))
(unless (equal? real-ans right-ans)
(printf "Test failed: ~e gave ~e. Expected ~e\n"
'code real-ans 'right-ans))) ...))))
#;(define-syntax test-block
(define-syntax test-block
(syntax-rules ()
((_ x ...) (void))))
@ -32,22 +31,23 @@
;; returned.
;; Xs are compared with equal?
(define (make-cache)
(let ([table (make-hash)])
(λ (key build)
(hash-ref table key (λ ()
(let ([new (build)])
(let ((table (make-hash)))
(lambda (key build)
(hash-ref table key
(lambda ()
(let ((new (build)))
(hash-set! table key new)
new))))))
(module+ test
(define cache (make-cache))
(check-equal? (cache '(s 1 2) (λ () 9)) 9)
(check-equal? (cache '(s 2 1) (λ () 8)) 8)
(check-equal? (cache '(s 1 2) (λ () 1)) 9)
(check-equal? (cache '(s 1 2) (lambda () 9)) 9)
(check-equal? (cache '(s 2 1) (lambda () 8)) 8)
(check-equal? (cache '(s 1 2) (lambda () 1)) 9)
(check-equal? (cache (cons 's (cons 0 (cons +inf.0 10)))
(λ () 22)) 22)
(lambda () 22)) 22)
(check-equal? (cache (cons 's (cons 0 (cons +inf.0 10)))
(λ () 1)) 22))
(lambda () 1)) 22))
@ -55,8 +55,8 @@
;; makes a function that returns a higher number by 1, each time
;; it is called.
(define (make-counter)
(let ([counter 0])
(λ ()
(let ((counter 0))
(lambda ()
(begin0
counter
(set! counter (add1 counter))))))
@ -76,12 +76,12 @@
;; previous entry. l must be grouped by indexes.
(define (remove-dups l index acc)
(cond
[(null? l) (reverse acc)]
[(null? acc) (remove-dups (cdr l) index (cons (car l) acc))]
[(= (index (car acc)) (index (car l)))
(remove-dups (cdr l) index acc)]
[else
(remove-dups (cdr l) index (cons (car l) acc))]))
((null? l) (reverse acc))
((null? acc) (remove-dups (cdr l) index (cons (car l) acc)))
((= (index (car acc)) (index (car l)))
(remove-dups (cdr l) index acc))
(else
(remove-dups (cdr l) index (cons (car l) acc)))))
(module+ test
@ -94,8 +94,8 @@
;; Sorts l according to index and removes the entries with duplicate
;; indexes.
(define (do-simple-equiv l index)
(define ordered (sort l (λ (a b) (< (index a) (index b)))))
(remove-dups ordered index null))
(let ((ordered (sort l (lambda (a b) (< (index a) (index b))))))
(remove-dups ordered index null)))
(module+ test
(check-equal? (do-simple-equiv '((2 2) (1 4) (1 2)
@ -110,16 +110,16 @@
;; list.
(define (replace l pred? get acc)
(cond
[(null? l) acc]
[(pred? (car l)) (replace (cdr l) pred? get (append (get (car l)) acc))]
[else (replace (cdr l) pred? get (cons (car l) acc))]))
((null? l) acc)
((pred? (car l)) (replace (cdr l) pred? get (append (get (car l)) acc)))
(else (replace (cdr l) pred? get (cons (car l) acc)))))
(module+ test
(check-equal? (replace null void (λ () (list 1)) null) null)
(check-equal? (replace null void (lambda () (list 1)) null) null)
(check-equal? (replace '(1 2 3 4 3 5)
(λ (x) (= x 3))
(λ (x) (list 1 2 3))
(lambda (x) (= x 3))
(lambda (x) (list 1 2 3))
null)
'(5 1 2 3 4 1 2 3 2 1)))

280
parser-tools-lib/parser-tools/private-yacc/grammar.rkt
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@ -0,0 +1,280 @@
;; Constructs to create and access grammars, the internal
;; representation of the input to the parser generator.
(module grammar mzscheme
(require mzlib/class
mzlib/list
"yacc-helper.rkt"
racket/contract)
;; Each production has a unique index 0 <= index <= number of productions
(define-struct prod (lhs rhs index prec action) (make-inspector))
;; The dot-pos field is the index of the element in the rhs
;; of prod that the dot immediately precedes.
;; Thus 0 <= dot-pos <= (vector-length rhs).
(define-struct item (prod dot-pos) (make-inspector))
;; gram-sym = (union term? non-term?)
;; Each term has a unique index 0 <= index < number of terms
;; Each non-term has a unique index 0 <= index < number of non-terms
(define-struct term (sym index prec) (make-inspector))
(define-struct non-term (sym index) (make-inspector))
;; a precedence declaration.
(define-struct prec (num assoc) (make-inspector))
(provide/contract
(make-item (prod? (or/c #f natural-number/c) . -> . item?))
(make-term (symbol? (or/c #f natural-number/c) (or/c prec? #f) . -> . term?))
(make-non-term (symbol? (or/c #f natural-number/c) . -> . non-term?))
(make-prec (natural-number/c (or/c 'left 'right 'nonassoc) . -> . prec?))
(make-prod (non-term? (vectorof (or/c non-term? term?))
(or/c #f natural-number/c) (or/c #f prec?) syntax? . -> . prod?)))
(provide
;; Things that work on items
start-item? item-prod item->string
sym-at-dot move-dot-right item<? item-dot-pos
;; Things that operate on grammar symbols
gram-sym-symbol gram-sym-index term-prec gram-sym->string
non-term? term? non-term<? term<?
term-list->bit-vector term-index non-term-index
;; Things that work on precs
prec-num prec-assoc
grammar%
;; Things that work on productions
prod-index prod-prec prod-rhs prod-lhs prod-action)
;;---------------------- LR items --------------------------
;; item<?: LR-item * LR-item -> bool
;; Lexicographic comparison on two items.
(define (item<? i1 i2)
(let ((p1 (prod-index (item-prod i1)))
(p2 (prod-index (item-prod i2))))
(or (< p1 p2)
(and (= p1 p2)
(let ((d1 (item-dot-pos i1))
(d2 (item-dot-pos i2)))
(< d1 d2))))))
;; start-item?: LR-item -> bool
;; The start production always has index 0
(define (start-item? i)
(= 0 (non-term-index (prod-lhs (item-prod i)))))
;; move-dot-right: LR-item -> LR-item | #f
;; moves the dot to the right in the item, unless it is at its
;; rightmost, then it returns false
(define (move-dot-right i)
(cond
((= (item-dot-pos i) (vector-length (prod-rhs (item-prod i)))) #f)
(else (make-item (item-prod i)
(add1 (item-dot-pos i))))))
;; sym-at-dot: LR-item -> gram-sym | #f
;; returns the symbol after the dot in the item or #f if there is none
(define (sym-at-dot i)
(let ((dp (item-dot-pos i))
(rhs (prod-rhs (item-prod i))))
(cond
((= dp (vector-length rhs)) #f)
(else (vector-ref rhs dp)))))
;; print-item: LR-item ->
(define (item->string it)
(let ((print-sym (lambda (i)
(let ((gs (vector-ref (prod-rhs (item-prod it)) i)))
(cond
((term? gs) (format "~a " (term-sym gs)))
(else (format "~a " (non-term-sym gs))))))))
(string-append
(format "~a -> " (non-term-sym (prod-lhs (item-prod it))))
(let loop ((i 0))
(cond
((= i (vector-length (prod-rhs (item-prod it))))
(if (= i (item-dot-pos it))
". "
""))
((= i (item-dot-pos it))
(string-append ". " (print-sym i) (loop (add1 i))))
(else (string-append (print-sym i) (loop (add1 i)))))))))
;; --------------------- Grammar Symbols --------------------------
(define (non-term<? nt1 nt2)
(< (non-term-index nt1) (non-term-index nt2)))
(define (term<? nt1 nt2)
(< (term-index nt1) (term-index nt2)))
(define (gram-sym-index gs)
(cond
((term? gs) (term-index gs))
(else (non-term-index gs))))
(define (gram-sym-symbol gs)
(cond
((term? gs) (term-sym gs))
(else (non-term-sym gs))))
(define (gram-sym->string gs)
(symbol->string (gram-sym-symbol gs)))
;; term-list->bit-vector: term list -> int
;; Creates a number where the nth bit is 1 if the term with index n is in
;; the list, and whose nth bit is 0 otherwise
(define (term-list->bit-vector terms)
(cond
((null? terms) 0)
(else
(bitwise-ior (arithmetic-shift 1 (term-index (car terms))) (term-list->bit-vector (cdr terms))))))
;; ------------------------- Grammar ------------------------------
(define grammar%
(class object%
(super-instantiate ())
;; prods: production list list
;; where there is one production list per non-term
(init prods)
;; init-prods: production list
;; The productions parsing can start from
;; nullable-non-terms is indexed by the non-term-index and is true iff non-term is nullable
(init-field init-prods terms non-terms end-terms)
;; list of all productions
(define all-prods (apply append prods))
(define num-prods (length all-prods))
(define num-terms (length terms))
(define num-non-terms (length non-terms))
(let ((count 0))
(for-each
(lambda (nt)
(set-non-term-index! nt count)
(set! count (add1 count)))
non-terms))
(let ((count 0))
(for-each
(lambda (t)
(set-term-index! t count)
(set! count (add1 count)))
terms))
(let ((count 0))
(for-each
(lambda (prod)
(set-prod-index! prod count)
(set! count (add1 count)))
all-prods))
;; indexed by the index of the non-term - contains the list of productions for that non-term
(define nt->prods
(let ((v (make-vector (length prods) #f)))
(for-each (lambda (prods)
(vector-set! v (non-term-index (prod-lhs (car prods))) prods))
prods)
v))
(define nullable-non-terms
(nullable all-prods num-non-terms))
(define/public (get-num-terms) num-terms)
(define/public (get-num-non-terms) num-non-terms)
(define/public (get-prods-for-non-term nt)
(vector-ref nt->prods (non-term-index nt)))
(define/public (get-prods) all-prods)
(define/public (get-init-prods) init-prods)
(define/public (get-terms) terms)
(define/public (get-non-terms) non-terms)
(define/public (get-num-prods) num-prods)
(define/public (get-end-terms) end-terms)
(define/public (nullable-non-term? nt)
(vector-ref nullable-non-terms (non-term-index nt)))
(define/public (nullable-after-dot? item)
(let* ((rhs (prod-rhs (item-prod item)))
(prod-length (vector-length rhs)))
(let loop ((i (item-dot-pos item)))
(cond
((< i prod-length)
(if (and (non-term? (vector-ref rhs i)) (nullable-non-term? (vector-ref rhs i)))
(loop (add1 i))
#f))
((= i prod-length) #t)))))
(define/public (nullable-non-term-thunk)
(lambda (nt)
(nullable-non-term? nt)))
(define/public (nullable-after-dot?-thunk)
(lambda (item)
(nullable-after-dot? item)))))
;; nullable: production list * int -> non-term set
;; determines which non-terminals can derive epsilon
(define (nullable prods num-nts)
(letrec ((nullable (make-vector num-nts #f))
(added #f)
;; possible-nullable: producion list -> production list
;; Removes all productions that have a terminal
(possible-nullable
(lambda (prods)
(filter (lambda (prod)
(vector-andmap non-term? (prod-rhs prod)))
prods)))
;; set-nullables: production list -> production list
;; makes one pass through the productions, adding the ones
;; known to be nullable now to nullable and returning a list
;; of productions that we don't know about yet.
(set-nullables
(lambda (prods)
(cond
((null? prods) null)
((vector-ref nullable
(gram-sym-index (prod-lhs (car prods))))
(set-nullables (cdr prods)))
((vector-andmap (lambda (nt)
(vector-ref nullable (gram-sym-index nt)))
(prod-rhs (car prods)))
(vector-set! nullable
(gram-sym-index (prod-lhs (car prods)))
#t)
(set! added #t)
(set-nullables (cdr prods)))
(else
(cons (car prods)
(set-nullables (cdr prods))))))))
(let loop ((P (possible-nullable prods)))
(cond
((null? P) nullable)
(else
(set! added #f)
(let ((new-P (set-nullables P)))
(if added
(loop new-P)
nullable)))))))
)

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parser-tools-lib/parser-tools/private-yacc/graph.rkt
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(module graph mzscheme
(provide digraph)
(define (zero-thunk) 0)
;; digraph:
;; ('a list) * ('a -> 'a list) * ('a -> 'b) * ('b * 'b -> 'b) * (-> 'b)
;; -> ('a -> 'b)
;; DeRemer and Pennello 1982
;; Computes (f x) = (f- x) union Union{(f y) | y in (edges x)}
;; We use a hash-table to represent the result function 'a -> 'b set, so
;; the values of type 'a must be comparable with eq?.
(define (digraph nodes edges f- union fail)
(letrec [
;; Will map elements of 'a to 'b sets
(results (make-hash-table))
(f (lambda (x) (hash-table-get results x fail)))
;; Maps elements of 'a to integers.
(N (make-hash-table))
(get-N (lambda (x) (hash-table-get N x zero-thunk)))
(set-N (lambda (x d) (hash-table-put! N x d)))
(stack null)
(push (lambda (x)
(set! stack (cons x stack))))
(pop (lambda ()
(begin0
(car stack)
(set! stack (cdr stack)))))
(depth (lambda () (length stack)))
;; traverse: 'a ->
(traverse
(lambda (x)
(push x)
(let ((d (depth)))
(set-N x d)
(hash-table-put! results x (f- x))
(for-each (lambda (y)
(if (= 0 (get-N y))
(traverse y))
(hash-table-put! results
x
(union (f x) (f y)))
(set-N x (min (get-N x) (get-N y))))
(edges x))
(if (= d (get-N x))
(let loop ((p (pop)))
(set-N p +inf.0)
(hash-table-put! results p (f x))
(if (not (eq? x p))
(loop (pop))))))))]
(for-each (lambda (x)
(if (= 0 (get-N x))
(traverse x)))
nodes)
f))
)

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parser-tools-lib/parser-tools/private-yacc/input-file-parser.rkt
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(module input-file-parser mzscheme
;; routines for parsing the input to the parser generator and producing a
;; grammar (See grammar.rkt)
(require "yacc-helper.rkt"
"../private-lex/token-syntax.rkt"
"grammar.rkt"
mzlib/class
racket/contract)
(require-for-template mzscheme)
(define (is-a-grammar%? x) (is-a? x grammar%))
(provide/contract
(parse-input ((listof identifier?) (listof identifier?) (listof identifier?)
(or/c #f syntax?) syntax? any/c . -> . is-a-grammar%?))
(get-term-list ((listof identifier?) . -> . (listof identifier?))))
(define stx-for-original-property (read-syntax #f (open-input-string "original")))
;; get-args: ??? -> (values (listof syntax) (or/c #f (cons integer? stx)))
(define (get-args i rhs src-pos term-defs)
(let ((empty-table (make-hash-table))
(biggest-pos #f))
(hash-table-put! empty-table 'error #t)
(for-each (lambda (td)
(let ((v (syntax-local-value td)))
(if (e-terminals-def? v)
(for-each (lambda (s)
(hash-table-put! empty-table (syntax-object->datum s) #t))
(syntax->list (e-terminals-def-t v))))))
term-defs)
(let ([args
(let get-args ((i i)
(rhs rhs))
(cond
((null? rhs) null)
(else
(let ((b (car rhs))
(name (if (hash-table-get empty-table (syntax-object->datum (car rhs)) (lambda () #f))
(gensym)
(string->symbol (format "$~a" i)))))
(cond
(src-pos
(let ([start-pos-id
(datum->syntax-object b (string->symbol (format "$~a-start-pos" i)) b stx-for-original-property)]
[end-pos-id
(datum->syntax-object b (string->symbol (format "$~a-end-pos" i)) b stx-for-original-property)])
(set! biggest-pos (cons start-pos-id end-pos-id))
`(,(datum->syntax-object b name b stx-for-original-property)
,start-pos-id
,end-pos-id
,@(get-args (add1 i) (cdr rhs)))))
(else
`(,(datum->syntax-object b name b stx-for-original-property)
,@(get-args (add1 i) (cdr rhs)))))))))])
(values args biggest-pos))))
;; Given the list of terminal symbols and the precedence/associativity definitions,
;; builds terminal structures (See grammar.rkt)
;; build-terms: symbol list * symbol list list -> term list
(define (build-terms term-list precs)
(let ((counter 0)
;;(term-list (cons (gensym) term-list))
;; Will map a terminal symbol to its precedence/associativity
(prec-table (make-hash-table)))
;; Fill the prec table
(for-each
(lambda (p-decl)
(begin0
(let ((assoc (car p-decl)))
(for-each
(lambda (term-sym)
(hash-table-put! prec-table term-sym (make-prec counter assoc)))
(cdr p-decl)))
(set! counter (add1 counter))))
precs)
;; Build the terminal structures
(map
(lambda (term-sym)
(make-term term-sym
#f
(hash-table-get prec-table term-sym (lambda () #f))))
term-list)))
;; Retrieves the terminal symbols from a terminals-def (See terminal-syntax.rkt)
;; get-terms-from-def: identifier? -> (listof identifier?)
(define (get-terms-from-def term-syn)
(let ((t (syntax-local-value term-syn (lambda () #f))))
(cond
((terminals-def? t) (syntax->list (terminals-def-t t)))
((e-terminals-def? t) (syntax->list (e-terminals-def-t t)))
(else
(raise-syntax-error
'parser-tokens
"undefined token group"
term-syn)))))
(define (get-term-list term-group-names)
(remove-duplicates
(cons (datum->syntax-object #f 'error)
(apply append
(map get-terms-from-def term-group-names)))))
(define (parse-input term-defs start ends prec-decls prods src-pos)
(let* ((start-syms (map syntax-e start))
(list-of-terms (map syntax-e (get-term-list term-defs)))
(end-terms
(map
(lambda (end)
(unless (memq (syntax-e end) list-of-terms)
(raise-syntax-error
'parser-end-tokens
(format "End token ~a not defined as a token"
(syntax-e end))
end))
(syntax-e end))
ends))
;; Get the list of terminals out of input-terms
(list-of-non-terms
(syntax-case prods ()
(((non-term production ...) ...)
(begin
(for-each
(lambda (nts)
(if (memq (syntax-object->datum nts) list-of-terms)
(raise-syntax-error
'parser-non-terminals
(format "~a used as both token and non-terminal"
(syntax-object->datum nts))
nts)))
(syntax->list (syntax (non-term ...))))
(let ((dup (duplicate-list? (syntax-object->datum
(syntax (non-term ...))))))
(if dup
(raise-syntax-error
'parser-non-terminals
(format "non-terminal ~a defined multiple times"
dup)
prods)))
(syntax-object->datum (syntax (non-term ...)))))
(_
(raise-syntax-error
'parser-grammar
"Grammar must be of the form (grammar (non-terminal productions ...) ...)"
prods))))
;; Check the precedence declarations for errors and turn them into data
(precs
(syntax-case prec-decls ()
(((type term ...) ...)
(let ((p-terms
(syntax-object->datum (syntax (term ... ...)))))
(cond
((duplicate-list? p-terms) =>
(lambda (d)
(raise-syntax-error
'parser-precedences
(format "duplicate precedence declaration for token ~a"
d)
prec-decls)))
(else
(for-each
(lambda (a)
(for-each
(lambda (t)
(if (not (memq (syntax-object->datum t)
list-of-terms))
(raise-syntax-error
'parser-precedences
(format
"Precedence declared for non-token ~a"
(syntax-object->datum t))
t)))
(syntax->list a)))
(syntax->list (syntax ((term ...) ...))))
(for-each
(lambda (type)
(if (not (memq (syntax-object->datum type)
`(left right nonassoc)))
(raise-syntax-error
'parser-precedences
"Associativity must be left, right or nonassoc"
type)))
(syntax->list (syntax (type ...))))
(syntax-object->datum prec-decls)))))
(#f null)
(_
(raise-syntax-error
'parser-precedences
"Precedence declaration must be of the form (precs (assoc term ...) ...) where assoc is left, right or nonassoc"
prec-decls))))
(terms (build-terms list-of-terms precs))
(non-terms (map (lambda (non-term) (make-non-term non-term #f))
list-of-non-terms))
(term-table (make-hash-table))
(non-term-table (make-hash-table)))
(for-each (lambda (t)
(hash-table-put! term-table (gram-sym-symbol t) t))
terms)
(for-each (lambda (nt)
(hash-table-put! non-term-table (gram-sym-symbol nt) nt))
non-terms)
(let* (
;; parse-prod: syntax-object -> gram-sym vector
(parse-prod
(lambda (prod-so)
(syntax-case prod-so ()
((prod-rhs-sym ...)
(andmap identifier? (syntax->list prod-so))
(begin
(for-each (lambda (t)
(if (memq (syntax-object->datum t) end-terms)
(raise-syntax-error
'parser-production-rhs
(format "~a is an end token and cannot be used in a production"
(syntax-object->datum t))
t)))
(syntax->list prod-so))
(list->vector
(map (lambda (s)
(hash-table-get
term-table
(syntax-object->datum s)
(lambda ()
(hash-table-get
non-term-table
(syntax-object->datum s)
(lambda ()
(raise-syntax-error
'parser-production-rhs
(format
"~a is not declared as a terminal or non-terminal"
(syntax-object->datum s))
s))))))
(syntax->list prod-so)))))
(_
(raise-syntax-error
'parser-production-rhs
"production right-hand-side must have form (symbol ...)"
prod-so)))))
;; parse-action: syntax-object * syntax-object -> syntax-object
(parse-action
(lambda (rhs act)
(let-values ([(args biggest) (get-args 1 (syntax->list rhs) src-pos term-defs)])
(let ([act
(if biggest
(with-syntax ([$n-start-pos (datum->syntax-object (car biggest) '$n-start-pos)]
[$n-end-pos (datum->syntax-object (cdr biggest) '$n-end-pos)])
#`(let ([$n-start-pos #,(car biggest)]
[$n-end-pos #,(cdr biggest)])
#,act))
act)])
(quasisyntax/loc act
(lambda #,args
#,act))))))
;; parse-prod+action: non-term * syntax-object -> production
(parse-prod+action
(lambda (nt prod-so)
(syntax-case prod-so ()
((prod-rhs action)
(let ((p (parse-prod (syntax prod-rhs))))
(make-prod
nt
p
#f
(let loop ((i (sub1 (vector-length p))))
(if (>= i 0)
(let ((gs (vector-ref p i)))
(if (term? gs)
(term-prec gs)
(loop (sub1 i))))
#f))
(parse-action (syntax prod-rhs) (syntax action)))))
((prod-rhs (prec term) action)
(identifier? (syntax term))
(let ((p (parse-prod (syntax prod-rhs))))
(make-prod
nt
p
#f
(term-prec
(hash-table-get
term-table
(syntax-object->datum (syntax term))
(lambda ()
(raise-syntax-error
'parser-production-rhs
(format
"unrecognized terminal ~a in precedence declaration"
(syntax-object->datum (syntax term)))
(syntax term)))))
(parse-action (syntax prod-rhs) (syntax action)))))
(_
(raise-syntax-error
'parser-production-rhs
"production must have form [(symbol ...) expression] or [(symbol ...) (prec symbol) expression]"
prod-so)))))
;; parse-prod-for-nt: syntax-object -> production list
(parse-prods-for-nt
(lambda (prods-so)
(syntax-case prods-so ()
((nt productions ...)
(> (length (syntax->list (syntax (productions ...)))) 0)
(let ((nt (hash-table-get non-term-table
(syntax-object->datum (syntax nt)))))
(map (lambda (p) (parse-prod+action nt p))
(syntax->list (syntax (productions ...))))))
(_
(raise-syntax-error
'parser-productions
"A production for a non-terminal must be (non-term right-hand-side ...) with at least 1 right hand side"
prods-so))))))
(for-each
(lambda (sstx ssym)
(unless (memq ssym list-of-non-terms)
(raise-syntax-error
'parser-start
(format "Start symbol ~a not defined as a non-terminal" ssym)
sstx)))
start start-syms)
(let* ((starts (map (lambda (x) (make-non-term (gensym) #f)) start-syms))
(end-non-terms (map (lambda (x) (make-non-term (gensym) #f)) start-syms))
(parsed-prods (map parse-prods-for-nt (syntax->list prods)))
(start-prods
(map (lambda (start end-non-term)
(list (make-prod start (vector end-non-term) #f #f
(syntax (lambda (x) x)))))
starts end-non-terms))
(prods
`(,@start-prods
,@(map
(lambda (end-nt start-sym)
(map
(lambda (end)
(make-prod end-nt
(vector
(hash-table-get non-term-table start-sym)
(hash-table-get term-table end))
#f
#f
(syntax (lambda (x) x))))
end-terms))
end-non-terms start-syms)
,@parsed-prods)))
(make-object grammar%
prods
(map car start-prods)
terms
(append starts (append end-non-terms non-terms))
(map (lambda (term-name)
(hash-table-get term-table term-name))
end-terms)))))))

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parser-tools-lib/parser-tools/private-yacc/lalr.rkt
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(module lalr mzscheme
;; Compute LALR lookaheads from DeRemer and Pennello 1982
(require "lr0.rkt"
"grammar.rkt"
mzlib/list
mzlib/class)
(provide compute-LA)
;; compute-DR: LR0-automaton * grammar -> (trans-key -> term set)
;; computes for each state, non-term transition pair, the terminals
;; which can transition out of the resulting state
;; output term set is represented in bit-vector form
(define (compute-DR a g)
(lambda (tk)
(let ((r (send a run-automaton (trans-key-st tk) (trans-key-gs tk))))
(term-list->bit-vector
(filter
(lambda (term)
(send a run-automaton r term))
(send g get-terms))))))
;; compute-reads:
;; LR0-automaton * grammar -> (trans-key -> trans-key list)
(define (compute-reads a g)
(let ((nullable-non-terms
(filter (lambda (nt) (send g nullable-non-term? nt))
(send g get-non-terms))))
(lambda (tk)
(let ((r (send a run-automaton (trans-key-st tk) (trans-key-gs tk))))
(map (lambda (x) (make-trans-key r x))
(filter (lambda (non-term) (send a run-automaton r non-term))
nullable-non-terms))))))
;; compute-read: LR0-automaton * grammar -> (trans-key -> term set)
;; output term set is represented in bit-vector form
(define (compute-read a g)
(let* ((dr (compute-DR a g))
(reads (compute-reads a g)))
(digraph-tk->terml (send a get-mapped-non-term-keys)
reads
dr
(send a get-num-states))))
;; returns the list of all k such that state k transitions to state start on the
;; transitions in rhs (in order)
(define (run-lr0-backward a rhs dot-pos start num-states)
(let loop ((states (list start))
(i (sub1 dot-pos)))
(cond
((< i 0) states)
(else (loop (send a run-automaton-back states (vector-ref rhs i))
(sub1 i))))))
;; prod->items-for-include: grammar * prod * non-term -> lr0-item list
;; returns the list of all (B -> beta . nt gamma) such that prod = (B -> beta nt gamma)
;; and gamma =>* epsilon
(define (prod->items-for-include g prod nt)
(let* ((rhs (prod-rhs prod))
(rhs-l (vector-length rhs)))
(append (if (and (> rhs-l 0) (eq? nt (vector-ref rhs (sub1 rhs-l))))
(list (make-item prod (sub1 rhs-l)))
null)
(let loop ((i (sub1 rhs-l)))
(cond
((and (> i 0)
(non-term? (vector-ref rhs i))
(send g nullable-non-term? (vector-ref rhs i)))
(if (eq? nt (vector-ref rhs (sub1 i)))
(cons (make-item prod (sub1 i))
(loop (sub1 i)))
(loop (sub1 i))))
(else null))))))
;; prod-list->items-for-include: grammar * prod list * non-term -> lr0-item list
;; return the list of all (B -> beta . nt gamma) such that (B -> beta nt gamma) in prod-list
;; and gamma =>* epsilon
(define (prod-list->items-for-include g prod-list nt)
(apply append (map (lambda (prod) (prod->items-for-include g prod nt)) prod-list)))
;; comput-includes: lr0-automaton * grammar -> (trans-key -> trans-key list)
(define (compute-includes a g)
(let ((num-states (send a get-num-states))
(items-for-input-nt (make-vector (send g get-num-non-terms) null)))
(for-each
(lambda (input-nt)
(vector-set! items-for-input-nt (non-term-index input-nt)
(prod-list->items-for-include g (send g get-prods) input-nt)))
(send g get-non-terms))
(lambda (tk)
(let* ((goal-state (trans-key-st tk))
(non-term (trans-key-gs tk))
(items (vector-ref items-for-input-nt (non-term-index non-term))))
(trans-key-list-remove-dups
(apply append
(map (lambda (item)
(let* ((prod (item-prod item))
(rhs (prod-rhs prod))
(lhs (prod-lhs prod)))
(map (lambda (state)
(make-trans-key state lhs))
(run-lr0-backward a
rhs
(item-dot-pos item)
goal-state
num-states))))
items)))))))
;; compute-lookback: lr0-automaton * grammar -> (kernel * proc -> trans-key list)
(define (compute-lookback a g)
(let ((num-states (send a get-num-states)))
(lambda (state prod)
(map (lambda (k) (make-trans-key k (prod-lhs prod)))
(run-lr0-backward a (prod-rhs prod) (vector-length (prod-rhs prod)) state num-states)))))
;; compute-follow: LR0-automaton * grammar -> (trans-key -> term set)
;; output term set is represented in bit-vector form
(define (compute-follow a g includes)
(let ((read (compute-read a g)))
(digraph-tk->terml (send a get-mapped-non-term-keys)
includes
read
(send a get-num-states))))
;; compute-LA: LR0-automaton * grammar -> kernel * prod -> term set
;; output term set is represented in bit-vector form
(define (compute-LA a g)
(let* ((includes (compute-includes a g))
(lookback (compute-lookback a g))
(follow (compute-follow a g includes)))
(lambda (k p)
(let* ((l (lookback k p))
(f (map follow l)))
(apply bitwise-ior (cons 0 f))))))
(define (print-DR dr a g)
(print-input-st-sym dr "DR" a g print-output-terms))
(define (print-Read Read a g)
(print-input-st-sym Read "Read" a g print-output-terms))
(define (print-includes i a g)
(print-input-st-sym i "includes" a g print-output-st-nt))
(define (print-lookback l a g)
(print-input-st-prod l "lookback" a g print-output-st-nt))
(define (print-follow f a g)
(print-input-st-sym f "follow" a g print-output-terms))
(define (print-LA l a g)
(print-input-st-prod l "LA" a g print-output-terms))
(define (print-input-st-sym f name a g print-output)
(printf "~a:\n" name)
(send a for-each-state
(lambda (state)
(for-each
(lambda (non-term)
(let ((res (f (make-trans-key state non-term))))
(if (not (null? res))
(printf "~a(~a, ~a) = ~a\n"
name
state
(gram-sym-symbol non-term)
(print-output res)))))
(send g get-non-terms))))
(newline))
(define (print-input-st-prod f name a g print-output)
(printf "~a:\n" name)
(send a for-each-state
(lambda (state)
(for-each
(lambda (non-term)
(for-each
(lambda (prod)
(let ((res (f state prod)))
(if (not (null? res))
(printf "~a(~a, ~a) = ~a\n"
name
(kernel-index state)
(prod-index prod)
(print-output res)))))
(send g get-prods-for-non-term non-term)))
(send g get-non-terms)))))
(define (print-output-terms r)
(map
(lambda (p)
(gram-sym-symbol p))
r))
(define (print-output-st-nt r)
(map
(lambda (p)
(list
(kernel-index (trans-key-st p))
(gram-sym-symbol (trans-key-gs p))))
r))
;; init-tk-map : int -> (vectorof hashtable?)
(define (init-tk-map n)
(let ((v (make-vector n #f)))
(let loop ((i (sub1 (vector-length v))))
(when (>= i 0)
(vector-set! v i (make-hash-table))
(loop (sub1 i))))
v))
;; lookup-tk-map : (vectorof (symbol? int hashtable)) -> trans-key? -> int
(define (lookup-tk-map map)
(lambda (tk)
(let ((st (trans-key-st tk))
(gs (trans-key-gs tk)))
(hash-table-get (vector-ref map (kernel-index st))
(gram-sym-symbol gs)
(lambda () 0)))))
;; add-tk-map : (vectorof (symbol? int hashtable)) -> trans-key int ->
(define (add-tk-map map)
(lambda (tk v)
(let ((st (trans-key-st tk))
(gs (trans-key-gs tk)))
(hash-table-put! (vector-ref map (kernel-index st))
(gram-sym-symbol gs)
v))))
;; digraph-tk->terml:
;; (trans-key list) * (trans-key -> trans-key list) * (trans-key -> term list) * int * int * int
;; -> (trans-key -> term list)
;; DeRemer and Pennello 1982
;; Computes (f x) = (f- x) union Union{(f y) | y in (edges x)}
;; A specialization of digraph in the file graph.rkt
(define (digraph-tk->terml nodes edges f- num-states)
(letrec [
;; Will map elements of trans-key to term sets represented as bit vectors
(results (init-tk-map num-states))
;; Maps elements of trans-keys to integers.
(N (init-tk-map num-states))
(get-N (lookup-tk-map N))
(set-N (add-tk-map N))
(get-f (lookup-tk-map results))
(set-f (add-tk-map results))
(stack null)
(push (lambda (x)
(set! stack (cons x stack))))
(pop (lambda ()
(begin0
(car stack)
(set! stack (cdr stack)))))
(depth (lambda () (length stack)))
;; traverse: 'a ->
(traverse
(lambda (x)
(push x)
(let ((d (depth)))
(set-N x d)
(set-f x (f- x))
(for-each (lambda (y)
(when (= 0 (get-N y))
(traverse y))
(set-f x (bitwise-ior (get-f x) (get-f y)))
(set-N x (min (get-N x) (get-N y))))
(edges x))
(when (= d (get-N x))
(let loop ((p (pop)))
(set-N p +inf.0)
(set-f p (get-f x))
(unless (equal? x p)
(loop (pop))))))))]
(for-each (lambda (x)
(when (= 0 (get-N x))
(traverse x)))
nodes)
get-f))
)

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parser-tools-lib/parser-tools/private-yacc/lr0.rkt
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(module lr0 mzscheme
;; Handle the LR0 automaton
(require "grammar.rkt"
"graph.rkt"
mzlib/list
mzlib/class)
(provide build-lr0-automaton lr0%
(struct trans-key (st gs)) trans-key-list-remove-dups
kernel-items kernel-index)
;; kernel = (make-kernel (LR1-item list) index)
;; the list must be kept sorted according to item<? so that equal? can
;; be used to compare kernels
;; Each kernel is assigned a unique index, 0 <= index < number of states
;; trans-key = (make-trans-key kernel gram-sym)
(define-struct kernel (items index) (make-inspector))
(define-struct trans-key (st gs) (make-inspector))
(define (trans-key<? a b)
(let ((kia (kernel-index (trans-key-st a)))
(kib (kernel-index (trans-key-st b))))
(or (< kia kib)
(and (= kia kib)
(< (non-term-index (trans-key-gs a))
(non-term-index (trans-key-gs b)))))))
(define (trans-key-list-remove-dups tkl)
(let loop ((sorted (sort tkl trans-key<?)))
(cond
((null? sorted) null)
((null? (cdr sorted)) sorted)
(else
(if (and (= (non-term-index (trans-key-gs (car sorted)))
(non-term-index (trans-key-gs (cadr sorted))))
(= (kernel-index (trans-key-st (car sorted)))
(kernel-index (trans-key-st (cadr sorted)))))
(loop (cdr sorted))
(cons (car sorted) (loop (cdr sorted))))))))
;; build-transition-table : int (listof (cons/c trans-key X) ->
;; (vectorof (symbol X hashtable))
(define (build-transition-table num-states assoc)
(let ((transitions (make-vector num-states #f)))
(let loop ((i (sub1 (vector-length transitions))))
(when (>= i 0)
(vector-set! transitions i (make-hash-table))
(loop (sub1 i))))
(for-each
(lambda (trans-key/kernel)
(let ((tk (car trans-key/kernel)))
(hash-table-put! (vector-ref transitions (kernel-index (trans-key-st tk)))
(gram-sym-symbol (trans-key-gs tk))
(cdr trans-key/kernel))))
assoc)
transitions))
;; reverse-assoc : (listof (cons/c trans-key? kernel?)) ->
;; (listof (cons/c trans-key? (listof kernel?)))
(define (reverse-assoc assoc)
(let ((reverse-hash (make-hash-table 'equal))
(hash-table-add!
(lambda (ht k v)
(hash-table-put! ht k (cons v (hash-table-get ht k (lambda () null)))))))
(for-each
(lambda (trans-key/kernel)
(let ((tk (car trans-key/kernel)))
(hash-table-add! reverse-hash
(make-trans-key (cdr trans-key/kernel)
(trans-key-gs tk))
(trans-key-st tk))))
assoc)
(hash-table-map reverse-hash cons)))
;; kernel-list-remove-duplicates
;; LR0-automaton = object of class lr0%
(define lr0%
(class object%
(super-instantiate ())
;; term-assoc : (listof (cons/c trans-key? kernel?))
;; non-term-assoc : (listof (cons/c trans-key? kernel?))
;; states : (vectorof kernel?)
;; epsilons : ???
(init-field term-assoc non-term-assoc states epsilons)
(define transitions (build-transition-table (vector-length states)
(append term-assoc non-term-assoc)))
(define reverse-term-assoc (reverse-assoc term-assoc))
(define reverse-non-term-assoc (reverse-assoc non-term-assoc))
(define reverse-transitions
(build-transition-table (vector-length states)
(append reverse-term-assoc reverse-non-term-assoc)))
(define mapped-non-terms (map car non-term-assoc))
(define/public (get-mapped-non-term-keys)
mapped-non-terms)
(define/public (get-num-states)
(vector-length states))
(define/public (get-epsilon-trans)
epsilons)
(define/public (get-transitions)
(append term-assoc non-term-assoc))
;; for-each-state : (state ->) ->
;; Iteration over the states in an automaton
(define/public (for-each-state f)
(let ((num-states (vector-length states)))
(let loop ((i 0))
(if (< i num-states)
(begin
(f (vector-ref states i))
(loop (add1 i)))))))
;; run-automaton: kernel? gram-sym? -> (union kernel #f)
;; returns the state reached from state k on input s, or #f when k
;; has no transition on s
(define/public (run-automaton k s)
(hash-table-get (vector-ref transitions (kernel-index k))
(gram-sym-symbol s)
(lambda () #f)))
;; run-automaton-back : (listof kernel?) gram-sym? -> (listof kernel)
;; returns the list of states that can reach k by transitioning on s.
(define/public (run-automaton-back k s)
(apply append
(map
(lambda (k)
(hash-table-get (vector-ref reverse-transitions (kernel-index k))
(gram-sym-symbol s)
(lambda () null)))
k)))))
(define (union comp<?)
(letrec ((union
(lambda (l1 l2)
(cond
((null? l1) l2)
((null? l2) l1)
(else (let ((c1 (car l1))
(c2 (car l2)))
(cond
((comp<? c1 c2)
(cons c1 (union (cdr l1) l2)))
((comp<? c2 c1)
(cons c2 (union l1 (cdr l2))))
(else (union (cdr l1) l2)))))))))
union))
;; The kernels in the automaton are represented cannonically.
;; That is (equal? a b) <=> (eq? a b)
(define (kernel->string k)
(apply string-append
`("{" ,@(map (lambda (i) (string-append (item->string i) ", "))
(kernel-items k))
"}")))
;; build-LR0-automaton: grammar -> LR0-automaton
;; Constructs the kernels of the sets of LR(0) items of g
(define (build-lr0-automaton grammar)
; (printf "LR(0) automaton:\n")
(letrec (
(epsilons (make-hash-table 'equal))
(grammar-symbols (append (send grammar get-non-terms)
(send grammar get-terms)))
;; first-non-term: non-term -> non-term list
;; given a non-terminal symbol C, return those non-terminal
;; symbols A s.t. C -> An for some string of terminals and
;; non-terminals n where -> means a rightmost derivation in many
;; steps. Assumes that each non-term can be reduced to a string
;; of terms.
(first-non-term
(digraph (send grammar get-non-terms)
(lambda (nt)
(filter non-term?
(map (lambda (prod)
(sym-at-dot (make-item prod 0)))
(send grammar get-prods-for-non-term nt))))
(lambda (nt) (list nt))
(union non-term<?)
(lambda () null)))
;; closure: LR1-item list -> LR1-item list
;; Creates a set of items containing i s.t. if A -> n.Xm is in it,
;; X -> .o is in it too.
(LR0-closure
(lambda (i)
(cond
((null? i) null)
(else
(let ((next-gsym (sym-at-dot (car i))))
(cond
((non-term? next-gsym)
(cons (car i)
(append
(apply append
(map (lambda (non-term)
(map (lambda (x)
(make-item x 0))
(send grammar
get-prods-for-non-term
non-term)))
(first-non-term next-gsym)))
(LR0-closure (cdr i)))))
(else
(cons (car i) (LR0-closure (cdr i))))))))))
;; maps trans-keys to kernels
(automaton-term null)
(automaton-non-term null)
;; keeps the kernels we have seen, so we can have a unique
;; list for each kernel
(kernels (make-hash-table 'equal))
(counter 0)
;; goto: LR1-item list -> LR1-item list list
;; creates new kernels by moving the dot in each item in the
;; LR0-closure of kernel to the right, and grouping them by
;; the term/non-term moved over. Returns the kernels not
;; yet seen, and places the trans-keys into automaton
(goto
(lambda (kernel)
(let (
;; maps a gram-syms to a list of items
(table (make-hash-table))
;; add-item!:
;; (symbol (listof item) hashtable) item? ->
;; adds i into the table grouped with the grammar
;; symbol following its dot
(add-item!
(lambda (table i)
(let ((gs (sym-at-dot i)))
(cond
(gs
(let ((already
(hash-table-get table
(gram-sym-symbol gs)
(lambda () null))))
(unless (member i already)
(hash-table-put! table
(gram-sym-symbol gs)
(cons i already)))))
((= 0 (vector-length (prod-rhs (item-prod i))))
(let ((current (hash-table-get epsilons
kernel
(lambda () null))))
(hash-table-put! epsilons
kernel
(cons i current)))))))))
;; Group the items of the LR0 closure of the kernel
;; by the character after the dot
(for-each (lambda (item)
(add-item! table item))
(LR0-closure (kernel-items kernel)))
;; each group is a new kernel, with the dot advanced.
;; sorts the items in a kernel so kernels can be compared
;; with equal? for using the table kernels to make sure
;; only one representitive of each kernel is created
(filter
(lambda (x) x)
(map
(lambda (i)
(let* ((gs (car i))
(items (cadr i))
(new #f)
(new-kernel (sort
(filter (lambda (x) x)
(map move-dot-right items))
item<?))
(unique-kernel (hash-table-get
kernels
new-kernel
(lambda ()
(let ((k (make-kernel
new-kernel
counter)))
(set! new #t)
(set! counter (add1 counter))
(hash-table-put! kernels
new-kernel
k)
k)))))
(cond
((term? gs)
(set! automaton-term (cons (cons (make-trans-key kernel gs)
unique-kernel)
automaton-term)))
(else
(set! automaton-non-term (cons (cons (make-trans-key kernel gs)
unique-kernel)
automaton-non-term))))
#;(printf "~a -> ~a on ~a\n"
(kernel->string kernel)
(kernel->string unique-kernel)
(gram-sym-symbol gs))
(if new
unique-kernel
#f)))
(let loop ((gsyms grammar-symbols))
(cond
((null? gsyms) null)
(else
(let ((items (hash-table-get table
(gram-sym-symbol (car gsyms))
(lambda () null))))
(cond
((null? items) (loop (cdr gsyms)))
(else
(cons (list (car gsyms) items)
(loop (cdr gsyms))))))))))))))
(starts
(map (lambda (init-prod) (list (make-item init-prod 0)))
(send grammar get-init-prods)))
(startk
(map (lambda (start)
(let ((k (make-kernel start counter)))
(hash-table-put! kernels start k)
(set! counter (add1 counter))
k))
starts))
(new-kernels (make-queue)))
(let loop ((old-kernels startk)
(seen-kernels null))
(cond
((and (empty-queue? new-kernels) (null? old-kernels))
(make-object lr0%
automaton-term
automaton-non-term
(list->vector (reverse seen-kernels))
epsilons))
((null? old-kernels)
(loop (deq! new-kernels) seen-kernels))
(else
(enq! new-kernels (goto (car old-kernels)))
(loop (cdr old-kernels) (cons (car old-kernels) seen-kernels)))))))
(define-struct q (f l) (make-inspector))
(define (empty-queue? q)
(null? (q-f q)))
(define (make-queue)
(make-q null null))
(define (enq! q i)
(if (empty-queue? q)
(let ((i (mcons i null)))
(set-q-l! q i)
(set-q-f! q i))
(begin
(set-mcdr! (q-l q) (mcons i null))
(set-q-l! q (mcdr (q-l q))))))
(define (deq! q)
(begin0
(mcar (q-f q))
(set-q-f! q (mcdr (q-f q)))))
)

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parser-tools-lib/parser-tools/private-yacc/parser-actions.rkt
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(module parser-actions mzscheme
(require "grammar.rkt")
(provide (all-defined-except make-reduce make-reduce*)
(rename make-reduce* make-reduce))
;; An action is
;; - (make-shift int)
;; - (make-reduce prod runtime-action)
;; - (make-accept)
;; - (make-goto int)
;; - (no-action)
;; A reduce contains a runtime-reduce so that sharing of the reduces can
;; be easily transferred to sharing of runtime-reduces.
(define-struct action () (make-inspector))
(define-struct (shift action) (state) (make-inspector))
(define-struct (reduce action) (prod runtime-reduce) (make-inspector))
(define-struct (accept action) () (make-inspector))
(define-struct (goto action) (state) (make-inspector))
(define-struct (no-action action) () (make-inspector))
(define (make-reduce* p)
(make-reduce p
(vector (prod-index p)
(gram-sym-symbol (prod-lhs p))
(vector-length (prod-rhs p)))))
;; A runtime-action is
;; non-negative-int (shift)
;; (vector int symbol int) (reduce)
;; 'accept (accept)
;; negative-int (goto)
;; #f (no-action)
(define (action->runtime-action a)
(cond
((shift? a) (shift-state a))
((reduce? a) (reduce-runtime-reduce a))
((accept? a) 'accept)
((goto? a) (- (+ (goto-state a) 1)))
((no-action? a) #f)))
(define (runtime-shift? x) (and (integer? x) (>= x 0)))
(define runtime-reduce? vector?)
(define (runtime-accept? x) (eq? x 'accept))
(define (runtime-goto? x) (and (integer? x) (< x 0)))
(define runtime-shift-state values)
(define (runtime-reduce-prod-num x) (vector-ref x 0))
(define (runtime-reduce-lhs x) (vector-ref x 1))
(define (runtime-reduce-rhs-length x) (vector-ref x 2))
(define (runtime-goto-state x) (- (+ x 1)))
)

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parser-tools-lib/parser-tools/private-yacc/parser-builder.rkt
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(module parser-builder mzscheme
(require "input-file-parser.rkt"
"grammar.rkt"
"table.rkt"
mzlib/class
racket/contract)
(require-for-template mzscheme)
(provide/contract
(build-parser (-> string? any/c any/c
(listof identifier?)
(listof identifier?)
(listof identifier?)
(or/c syntax? #f)
syntax?
(values any/c any/c any/c any/c))))
;; fix-check-syntax : (listof identifier?) (listof identifier?) (listof identifier?)
;; (union syntax? false/c) syntax?) -> syntax?
(define (fix-check-syntax input-terms start ends assocs prods)
(let* ((term-binders (get-term-list input-terms))
(get-term-binder
(let ((t (make-hash-table)))
(for-each
(lambda (term)
(hash-table-put! t (syntax-e term) term))
term-binders)
(lambda (x)
(let ((r (hash-table-get t (syntax-e x) (lambda () #f))))
(if r
(syntax-local-introduce (datum->syntax-object r (syntax-e x) x x))
x)))))
(rhs-list
(syntax-case prods ()
(((_ rhs ...) ...)
(syntax->list (syntax (rhs ... ...)))))))
(with-syntax (((tmp ...) (map syntax-local-introduce term-binders))
((term-group ...)
(map (lambda (tg)
(syntax-property
(datum->syntax-object tg #f)
'disappeared-use
tg))
input-terms))
((end ...)
(map get-term-binder ends))
((start ...)
(map get-term-binder start))
((bind ...)
(syntax-case prods ()
(((bind _ ...) ...)
(syntax->list (syntax (bind ...))))))
(((bound ...) ...)
(map
(lambda (rhs)
(syntax-case rhs ()
(((bound ...) (_ pbound) __)
(map get-term-binder
(cons (syntax pbound)
(syntax->list (syntax (bound ...))))))
(((bound ...) _)
(map get-term-binder
(syntax->list (syntax (bound ...)))))))
rhs-list))
((prec ...)
(if assocs
(map get-term-binder
(syntax-case assocs ()
(((__ term ...) ...)
(syntax->list (syntax (term ... ...))))))
null)))
#`(when #f
(let ((bind void) ... (tmp void) ...)
(void bound ... ... term-group ... start ... end ... prec ...))))))
(require mzlib/list "parser-actions.rkt")
(define (build-parser filename src-pos suppress input-terms start end assocs prods)
(let* ((grammar (parse-input input-terms start end assocs prods src-pos))
(table (build-table grammar filename suppress))
(all-tokens (make-hash-table))
(actions-code
`(vector ,@(map prod-action (send grammar get-prods)))))
(for-each (lambda (term)
(hash-table-put! all-tokens (gram-sym-symbol term) #t))
(send grammar get-terms))
#;(let ((num-states (vector-length table))
(num-gram-syms (+ (send grammar get-num-terms)
(send grammar get-num-non-terms)))
(num-ht-entries (apply + (map length (vector->list table))))
(num-reduces
(let ((ht (make-hash-table)))
(for-each
(lambda (x)
(when (reduce? x)
(hash-table-put! ht x #t)))
(map cdr (apply append (vector->list table))))
(length (hash-table-map ht void)))))
(printf "~a states, ~a grammar symbols, ~a hash-table entries, ~a reduces\n"
num-states num-gram-syms num-ht-entries num-reduces)
(printf "~a -- ~aKB, previously ~aKB\n"
(/ (+ 2 num-states
(* 4 num-states) (* 2 1.5 num-ht-entries)
(* 5 num-reduces)) 256.0)
(/ (+ 2 num-states
(* 4 num-states) (* 2 2.3 num-ht-entries)
(* 5 num-reduces)) 256.0)
(/ (+ 2 (* num-states num-gram-syms) (* 5 num-reduces)) 256.0)))
(values table
all-tokens
actions-code
(fix-check-syntax input-terms start end assocs prods))))
)

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parser-tools-lib/parser-tools/private-yacc/table.rkt
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#lang scheme/base
;; Routine to build the LALR table
(require "grammar.rkt"
"lr0.rkt"
"lalr.rkt"
"parser-actions.rkt"
racket/contract
mzlib/list
mzlib/class)
(define (is-a-grammar%? x) (is-a? x grammar%))
(provide/contract
(build-table (-> is-a-grammar%? string? any/c
(vectorof (listof (cons/c (or/c term? non-term?) action?))))))
;; A parse-table is (vectorof (listof (cons/c gram-sym? action)))
;; A grouped-parse-table is (vectorof (listof (cons/c gram-sym? (listof action))))
;; make-parse-table : int -> parse-table
(define (make-parse-table num-states)
(make-vector num-states null))
;; table-add!: parse-table nat symbol action ->
(define (table-add! table state-index symbol val)
(vector-set! table state-index (cons (cons symbol val)
(vector-ref table state-index))))
;; group-table : parse-table -> grouped-parse-table
(define (group-table table)
(list->vector
(map
(lambda (state-entry)
(let ((ht (make-hash)))
(for-each
(lambda (gs/actions)
(let ((group (hash-ref ht (car gs/actions) (lambda () null))))
(unless (member (cdr gs/actions) group)
(hash-set! ht (car gs/actions) (cons (cdr gs/actions) group)))))
state-entry)
(hash-map ht cons)))
(vector->list table))))
;; table-map : (vectorof (listof (cons/c gram-sym? X))) (gram-sym? X -> Y) ->
;; (vectorof (listof (cons/c gram-sym? Y)))
(define (table-map f table)
(list->vector
(map
(lambda (state-entry)
(map
(lambda (gs/X)
(cons (car gs/X) (f (car gs/X) (cdr gs/X))))
state-entry))
(vector->list table))))
(define (bit-vector-for-each f bv)
(letrec ((for-each
(lambda (bv number)
(cond
((= 0 bv) (void))
((= 1 (bitwise-and 1 bv))
(f number)
(for-each (arithmetic-shift bv -1) (add1 number)))
(else (for-each (arithmetic-shift bv -1) (add1 number)))))))
(for-each bv 0)))
;; print-entry: symbol action output-port ->
;; prints the action a for lookahead sym to the given port
(define (print-entry sym a port)
(let ((s "\t~a\t\t\t\t\t~a\t~a\n"))
(cond
((shift? a)
(fprintf port s sym "shift" (shift-state a)))
((reduce? a)
(fprintf port s sym "reduce" (prod-index (reduce-prod a))))
((accept? a)
(fprintf port s sym "accept" ""))
((goto? a)
(fprintf port s sym "goto" (goto-state a))))))
;; count: ('a -> bool) * 'a list -> num
;; counts the number of elements in list that satisfy pred
(define (count pred list)
(cond
((null? list) 0)
((pred (car list)) (+ 1 (count pred (cdr list))))
(else (count pred (cdr list)))))
;; display-parser: LR0-automaton grouped-parse-table (listof prod?) output-port ->
;; Prints out the parser given by table.
(define (display-parser a grouped-table prods port)
(let* ((SR-conflicts 0)
(RR-conflicts 0))
(for-each
(lambda (prod)
(fprintf port
"~a\t~a\t=\t~a\n"
(prod-index prod)
(gram-sym-symbol (prod-lhs prod))
(map gram-sym-symbol (vector->list (prod-rhs prod)))))
prods)
(send a for-each-state
(lambda (state)
(fprintf port "State ~a\n" (kernel-index state))
(for-each (lambda (item)
(fprintf port "\t~a\n" (item->string item)))
(kernel-items state))
(newline port)
(for-each
(lambda (gs/action)
(let ((sym (gram-sym-symbol (car gs/action)))
(act (cdr gs/action)))
(cond
((null? act) (void))
((null? (cdr act))
(print-entry sym (car act) port))
(else
(fprintf port "begin conflict:\n")
(when (> (count reduce? act) 1)
(set! RR-conflicts (add1 RR-conflicts)))
(when (> (count shift? act) 0)
(set! SR-conflicts (add1 SR-conflicts)))
(map (lambda (x) (print-entry sym x port)) act)
(fprintf port "end conflict\n")))))
(vector-ref grouped-table (kernel-index state)))
(newline port)))
(when (> SR-conflicts 0)
(fprintf port "~a shift/reduce conflict~a\n"
SR-conflicts
(if (= SR-conflicts 1) "" "s")))
(when (> RR-conflicts 0)
(fprintf port "~a reduce/reduce conflict~a\n"
RR-conflicts
(if (= RR-conflicts 1) "" "s")))))
;; resolve-conflict : (listof action?) -> action? bool bool
(define (resolve-conflict actions)
(cond
((null? actions) (values (make-no-action) #f #f))
((null? (cdr actions))
(values (car actions) #f #f))
(else
(let ((SR-conflict? (> (count shift? actions) 0))
(RR-conflict? (> (count reduce? actions) 1)))
(let loop ((current-guess #f)
(rest actions))
(cond
((null? rest) (values current-guess SR-conflict? RR-conflict?))
((shift? (car rest)) (values (car rest) SR-conflict? RR-conflict?))
((not current-guess)
(loop (car rest) (cdr rest)))
((and (reduce? (car rest))
(< (prod-index (reduce-prod (car rest)))
(prod-index (reduce-prod current-guess))))
(loop (car rest) (cdr rest)))
((accept? (car rest))
(eprintf "accept/reduce or accept/shift conflicts. Check the grammar for useless cycles of productions\n")
(loop current-guess (cdr rest)))
(else (loop current-guess (cdr rest)))))))))
;; resolve-conflicts : grouped-parse-table bool -> parse-table
(define (resolve-conflicts grouped-table suppress)
(let* ((SR-conflicts 0)
(RR-conflicts 0)
(table (table-map
(lambda (gs actions)
(let-values (((action SR? RR?)
(resolve-conflict actions)))
(when SR?
(set! SR-conflicts (add1 SR-conflicts)))
(when RR?
(set! RR-conflicts (add1 RR-conflicts)))
action))
grouped-table)))
(unless suppress
(when (> SR-conflicts 0)
(eprintf "~a shift/reduce conflict~a\n"
SR-conflicts
(if (= SR-conflicts 1) "" "s")))
(when (> RR-conflicts 0)
(eprintf "~a reduce/reduce conflict~a\n"
RR-conflicts
(if (= RR-conflicts 1) "" "s"))))
table))
;; resolve-sr-conflict : (listof action) (union int #f) -> (listof action)
;; Resolves a single shift-reduce conflict, if precedences are in place.
(define (resolve-sr-conflict/prec actions shift-prec)
(let* ((shift (if (shift? (car actions))
(car actions)
(cadr actions)))
(reduce (if (shift? (car actions))
(cadr actions)
(car actions)))
(reduce-prec (prod-prec (reduce-prod reduce))))
(cond
((and shift-prec reduce-prec)
(cond
((< (prec-num shift-prec) (prec-num reduce-prec))
(list reduce))
((> (prec-num shift-prec) (prec-num reduce-prec))
(list shift))
((eq? 'left (prec-assoc shift-prec))
(list reduce))
((eq? 'right (prec-assoc shift-prec))
(list shift))
(else null)))
(else actions))))
;; resolve-prec-conflicts : parse-table -> grouped-parse-table
(define (resolve-prec-conflicts table)
(table-map
(lambda (gs actions)
(cond
((and (term? gs)
(= 2 (length actions))
(or (shift? (car actions))
(shift? (cadr actions))))
(resolve-sr-conflict/prec actions (term-prec gs)))
(else actions)))
(group-table table)))
;; build-table: grammar string bool -> parse-table
(define (build-table g file suppress)
(let* ((a (build-lr0-automaton g))
(term-vector (list->vector (send g get-terms)))
(end-terms (send g get-end-terms))
(table (make-parse-table (send a get-num-states)))
(get-lookahead (compute-LA a g))
(reduce-cache (make-hash)))
(for-each
(lambda (trans-key/state)
(let ((from-state-index (kernel-index (trans-key-st (car trans-key/state))))
(gs (trans-key-gs (car trans-key/state)))
(to-state (cdr trans-key/state)))
(table-add! table from-state-index gs
(cond
((non-term? gs)
(make-goto (kernel-index to-state)))
((member gs end-terms)
(make-accept))
(else
(make-shift
(kernel-index to-state)))))))
(send a get-transitions))
(send a for-each-state
(lambda (state)
(for-each
(lambda (item)
(let ((item-prod (item-prod item)))
(bit-vector-for-each
(lambda (term-index)
(unless (start-item? item)
(let ((r (hash-ref reduce-cache item-prod
(lambda ()
(let ((r (make-reduce item-prod)))
(hash-set! reduce-cache item-prod r)
r)))))
(table-add! table
(kernel-index state)
(vector-ref term-vector term-index)
r))))
(get-lookahead state item-prod))))
(append (hash-ref (send a get-epsilon-trans) state (lambda () null))
(filter (lambda (item)
(not (move-dot-right item)))
(kernel-items state))))))
(let ((grouped-table (resolve-prec-conflicts table)))
(unless (string=? file "")
(with-handlers [(exn:fail:filesystem?
(lambda (e)
(eprintf
"Cannot write debug output to file \"~a\": ~a\n"
file
(exn-message e))))]
(call-with-output-file file
(lambda (port)
(display-parser a grouped-table (send g get-prods) port))
#:exists 'truncate)))
(resolve-conflicts grouped-table suppress))))

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parser-tools-lib/parser-tools/private-yacc/yacc-helper.rkt
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(module yacc-helper mzscheme
(require mzlib/list
"../private-lex/token-syntax.rkt")
;; General helper routines
(provide duplicate-list? remove-duplicates overlap? vector-andmap display-yacc)
(define (vector-andmap f v)
(let loop ((i 0))
(cond
((= i (vector-length v)) #t)
(else (if (f (vector-ref v i))
(loop (add1 i))
#f)))))
;; duplicate-list?: symbol list -> #f | symbol
;; returns a symbol that exists twice in l, or false if no such symbol
;; exists
(define (duplicate-list? l)
(letrec ((t (make-hash-table))
(dl? (lambda (l)
(cond
((null? l) #f)
((hash-table-get t (car l) (lambda () #f)) =>
(lambda (x) x))
(else
(hash-table-put! t (car l) (car l))
(dl? (cdr l)))))))
(dl? l)))
;; remove-duplicates: syntax-object list -> syntax-object list
;; removes the duplicates from the lists
(define (remove-duplicates sl)
(let ((t (make-hash-table)))
(letrec ((x
(lambda (sl)
(cond
((null? sl) sl)
((hash-table-get t (syntax-object->datum (car sl)) (lambda () #f))
(x (cdr sl)))
(else
(hash-table-put! t (syntax-object->datum (car sl)) #t)
(cons (car sl) (x (cdr sl))))))))
(x sl))))
;; overlap?: symbol list * symbol list -> #f | symbol
;; Returns an symbol in l1 intersect l2, or #f is no such symbol exists
(define (overlap? l1 l2)
(let/ec ret
(let ((t (make-hash-table)))
(for-each (lambda (s1)
(hash-table-put! t s1 s1))
l1)
(for-each (lambda (s2)
(cond
((hash-table-get t s2 (lambda () #f)) =>
(lambda (o) (ret o)))))
l2)
#f)))
(define (display-yacc grammar tokens start precs port)
(let-syntax ((p (syntax-rules ()
((_ args ...) (fprintf port args ...)))))
(let* ((tokens (map syntax-local-value tokens))
(eterms (filter e-terminals-def? tokens))
(terms (filter terminals-def? tokens))
(term-table (make-hash-table))
(display-rhs
(lambda (rhs)
(for-each (lambda (sym) (p "~a " (hash-table-get term-table sym (lambda () sym))))
(car rhs))
(if (= 3 (length rhs))
(p "%prec ~a" (cadadr rhs)))
(p "\n"))))
(for-each
(lambda (t)
(for-each
(lambda (t)
(hash-table-put! term-table t (format "'~a'" t)))
(syntax-object->datum (e-terminals-def-t t))))
eterms)
(for-each
(lambda (t)
(for-each
(lambda (t)
(p "%token ~a\n" t)
(hash-table-put! term-table t (format "~a" t)))
(syntax-object->datum (terminals-def-t t))))
terms)
(if precs
(for-each (lambda (prec)
(p "%~a " (car prec))
(for-each (lambda (tok)
(p " ~a" (hash-table-get term-table tok)))
(cdr prec))
(p "\n"))
precs))
(p "%start ~a\n" start)
(p "%%\n")
(for-each (lambda (prod)
(let ((nt (car prod)))
(p "~a: " nt)
(display-rhs (cadr prod))
(for-each (lambda (rhs)
(p "| ")
(display-rhs rhs))
(cddr prod))
(p ";\n")))
grammar)
(p "%%\n"))))
)

135
parser-tools-lib/parser-tools/yacc-to-scheme.rkt
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(module yacc-to-scheme mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre)
parser-tools/yacc
syntax/readerr
mzlib/list)
(provide trans)
(define match-double-string
(lexer
((:+ (:~ #\" #\\)) (append (string->list lexeme)
(match-double-string input-port)))
((:: #\\ any-char) (cons (string-ref lexeme 1) (match-double-string input-port)))
(#\" null)))
(define match-single-string
(lexer
((:+ (:~ #\' #\\)) (append (string->list lexeme)
(match-single-string input-port)))
((:: #\\ any-char) (cons (string-ref lexeme 1) (match-single-string input-port)))
(#\' null)))
(define-lex-abbrevs
(letter (:or (:/ "a" "z") (:/ "A" "Z")))
(digit (:/ "0" "9"))
(initial (:or letter (char-set "!$%&*/<=>?^_~@")))
(subsequent (:or initial digit (char-set "+-.@")))
(comment (:: "/*" (complement (:: any-string "*/" any-string)) "*/")))
(define-empty-tokens x
(EOF PIPE |:| SEMI |%%| %prec))
(define-tokens y
(SYM STRING))
(define get-token-grammar
(lexer-src-pos
("%%" '|%%|)
(":" (string->symbol lexeme))
("%prec" (string->symbol lexeme))
(#\| 'PIPE)
((:+ (:or #\newline #\tab " " comment (:: "{" (:* (:~ "}")) "}")))
(return-without-pos (get-token-grammar input-port)))
(#\; 'SEMI)
(#\' (token-STRING (string->symbol (list->string (match-single-string input-port)))))
(#\" (token-STRING (string->symbol (list->string (match-double-string input-port)))))
((:: initial (:* subsequent)) (token-SYM (string->symbol lexeme)))))
(define (parse-grammar enter-term enter-empty-term enter-non-term)
(parser
(tokens x y)
(src-pos)
(error (lambda (tok-ok tok-name tok-value start-pos end-pos)
(raise-read-error
(format "Error Parsing YACC grammar at token: ~a with value: ~a" tok-name tok-value)
(file-path)
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos) (position-offset start-pos)))))
(end |%%|)
(start gram)
(grammar
(gram
((production) (list $1))
((production gram) (cons $1 $2)))
(production
((SYM |:| prods SEMI)
(begin
(enter-non-term $1)
(cons $1 $3))))
(prods
((rhs) (list `(,$1 #f)))
((rhs prec) (list `(,$1 ,$2 #f)))
((rhs PIPE prods) (cons `(,$1 #f) $3))
((rhs prec PIPE prods) (cons `(,$1 ,$2 #f) $4)))
(prec
((%prec SYM)
(begin
(enter-term $2)
(list 'prec $2)))
((%prec STRING)
(begin
(enter-empty-term $2)
(list 'prec $2))))
(rhs
(() null)
((SYM rhs)
(begin
(enter-term $1)
(cons $1 $2)))
((STRING rhs)
(begin
(enter-empty-term $1)
(cons $1 $2)))))))
(define (symbol<? a b)
(string<? (symbol->string a) (symbol->string b)))
(define (trans filename)
(let* ((i (open-input-file filename))
(terms (make-hash-table))
(eterms (make-hash-table))
(nterms (make-hash-table))
(enter-term
(lambda (s)
(if (not (hash-table-get nterms s (lambda () #f)))
(hash-table-put! terms s #t))))
(enter-empty-term
(lambda (s)
(if (not (hash-table-get nterms s (lambda () #f)))
(hash-table-put! eterms s #t))))
(enter-non-term
(lambda (s)
(hash-table-remove! terms s)
(hash-table-remove! eterms s)
(hash-table-put! nterms s #t))))
(port-count-lines! i)
(file-path filename)
(regexp-match "%%" i)
(begin0
(let ((gram ((parse-grammar enter-term enter-empty-term enter-non-term)
(lambda ()
(let ((t (get-token-grammar i)))
t)))))
`(begin
(define-tokens t ,(sort (hash-table-map terms (lambda (k v) k)) symbol<?))
(define-empty-tokens et ,(sort (hash-table-map eterms (lambda (k v) k)) symbol<?))
(parser
(start ___)
(end ___)
(error ___)
(tokens t et)
(grammar ,@gram))))
(close-input-port i)))))

396
parser-tools-lib/parser-tools/yacc.rkt
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#lang scheme/base
(require (for-syntax scheme/base
"private-yacc/parser-builder.rkt"
"private-yacc/grammar.rkt"
"private-yacc/yacc-helper.rkt"
"private-yacc/parser-actions.rkt"))
(require "private-lex/token.rkt"
"private-yacc/parser-actions.rkt"
mzlib/etc
mzlib/pretty
syntax/readerr)
(provide parser)
;; convert-parse-table : (vectorof (listof (cons/c gram-sym? action?))) ->
;; (vectorof (symbol runtime-action hashtable))
(define-for-syntax (convert-parse-table table)
(list->vector
(map
(lambda (state-entry)
(let ((ht (make-hasheq)))
(for-each
(lambda (gs/action)
(hash-set! ht
(gram-sym-symbol (car gs/action))
(action->runtime-action (cdr gs/action))))
state-entry)
ht))
(vector->list table))))
(define-syntax (parser stx)
(syntax-case stx ()
((_ args ...)
(let ((arg-list (syntax->list (syntax (args ...))))
(src-pos #f)
(debug #f)
(error #f)
(tokens #f)
(start #f)
(end #f)
(precs #f)
(suppress #f)
(grammar #f)
(yacc-output #f))
(for-each
(lambda (arg)
(syntax-case* arg (debug error tokens start end precs grammar
suppress src-pos yacc-output)
(lambda (a b)
(eq? (syntax-e a) (syntax-e b)))
((debug filename)
(cond
((not (string? (syntax-e (syntax filename))))
(raise-syntax-error
#f
"Debugging filename must be a string"
stx
(syntax filename)))
(debug
(raise-syntax-error #f "Multiple debug declarations" stx))
(else
(set! debug (syntax-e (syntax filename))))))
((suppress)
(set! suppress #t))
((src-pos)
(set! src-pos #t))
((error expression)
(if error
(raise-syntax-error #f "Multiple error declarations" stx)
(set! error (syntax expression))))
((tokens def ...)
(begin
(when tokens
(raise-syntax-error #f "Multiple tokens declarations" stx))
(let ((defs (syntax->list (syntax (def ...)))))
(for-each
(lambda (d)
(unless (identifier? d)
(raise-syntax-error
#f
"Token-group name must be an identifier"
stx
d)))
defs)
(set! tokens defs))))
((start symbol ...)
(let ((symbols (syntax->list (syntax (symbol ...)))))
(for-each
(lambda (sym)
(unless (identifier? sym)
(raise-syntax-error #f
"Start symbol must be a symbol"
stx
sym)))
symbols)
(when start
(raise-syntax-error #f "Multiple start declarations" stx))
(when (null? symbols)
(raise-syntax-error #f
"Missing start symbol"
stx
arg))
(set! start symbols)))
((end symbols ...)
(let ((symbols (syntax->list (syntax (symbols ...)))))
(for-each
(lambda (sym)
(unless (identifier? sym)
(raise-syntax-error #f
"End token must be a symbol"
stx
sym)))
symbols)
(let ((d (duplicate-list? (map syntax-e symbols))))
(when d
(raise-syntax-error
#f
(format "Duplicate end token definition for ~a" d)
stx
arg))
(when (null? symbols)
(raise-syntax-error
#f
"end declaration must contain at least 1 token"
stx
arg))
(when end
(raise-syntax-error #f "Multiple end declarations" stx))
(set! end symbols))))
((precs decls ...)
(if precs
(raise-syntax-error #f "Multiple precs declarations" stx)
(set! precs (syntax/loc arg (decls ...)))))
((grammar prods ...)
(if grammar
(raise-syntax-error #f "Multiple grammar declarations" stx)
(set! grammar (syntax/loc arg (prods ...)))))
((yacc-output filename)
(cond
((not (string? (syntax-e (syntax filename))))
(raise-syntax-error #f
"Yacc-output filename must be a string"
stx
(syntax filename)))
(yacc-output
(raise-syntax-error #f "Multiple yacc-output declarations" stx))
(else
(set! yacc-output (syntax-e (syntax filename))))))
(_ (raise-syntax-error #f "argument must match (debug filename), (error expression), (tokens def ...), (start non-term), (end tokens ...), (precs decls ...), or (grammar prods ...)" stx arg))))
(syntax->list (syntax (args ...))))
(unless tokens
(raise-syntax-error #f "missing tokens declaration" stx))
(unless error
(raise-syntax-error #f "missing error declaration" stx))
(unless grammar
(raise-syntax-error #f "missing grammar declaration" stx))
(unless end
(raise-syntax-error #f "missing end declaration" stx))
(unless start
(raise-syntax-error #f "missing start declaration" stx))
(let-values (((table all-term-syms actions check-syntax-fix)
(build-parser (if debug debug "")
src-pos
suppress
tokens
start
end
precs
grammar)))
(when (and yacc-output (not (string=? yacc-output "")))
(with-handlers [(exn:fail:filesystem?
(lambda (e)
(eprintf
"Cannot write yacc-output to file \"~a\"\n"
yacc-output)))]
(call-with-output-file yacc-output
(lambda (port)
(display-yacc (syntax->datum grammar)
tokens
(map syntax->datum start)
(if precs
(syntax->datum precs)
#f)
port))
#:exists 'truncate)))
(with-syntax ((check-syntax-fix check-syntax-fix)
(err error)
(ends end)
(starts start)
(debug debug)
(table (convert-parse-table table))
(all-term-syms all-term-syms)
(actions actions)
(src-pos src-pos))
(syntax
(begin
check-syntax-fix
(parser-body debug err (quote starts) (quote ends) table all-term-syms actions src-pos)))))))
(_
(raise-syntax-error #f
"parser must have the form (parser args ...)"
stx))))
(define (reduce-stack stack num ret-vals src-pos)
(cond
((> num 0)
(let* ((top-frame (car stack))
(ret-vals
(if src-pos
(cons (stack-frame-value top-frame)
(cons (stack-frame-start-pos top-frame)
(cons (stack-frame-end-pos top-frame)
ret-vals)))
(cons (stack-frame-value top-frame) ret-vals))))
(reduce-stack (cdr stack) (sub1 num) ret-vals src-pos)))
(else (values stack ret-vals))))
;; extract-helper : (symbol or make-token) any any -> symbol any any any
(define (extract-helper tok v1 v2)
(cond
((symbol? tok)
(values tok #f v1 v2))
((token? tok)
(values (real-token-name tok) (real-token-value tok) v1 v2))
(else (raise-argument-error 'parser
"(or/c symbol? token?)"
0
tok))))
;; well-formed-position-token?: any -> boolean
;; Returns true if pt is a position token whose position-token-token
;; is itself a token or a symbol.
;; This is meant to help raise more precise error messages when
;; a tokenizer produces an erroneous position-token wrapped twice.
;; (as often happens when omitting return-without-pos).
(define (well-formed-position-token? pt)
(and (position-token? pt)
(let ([t (position-token-token pt)])
(or (symbol? t)
(token? t)))))
;; extract-src-pos : position-token -> symbol any any any
(define (extract-src-pos ip)
(cond
((well-formed-position-token? ip)
(extract-helper (position-token-token ip)
(position-token-start-pos ip)
(position-token-end-pos ip)))
(else
(raise-argument-error 'parser
"well-formed-position-token?"
0
ip))))
;; extract-no-src-pos : (symbol or make-token) -> symbol any any any
(define (extract-no-src-pos ip)
(extract-helper ip #f #f))
(define-struct stack-frame (state value start-pos end-pos) #:inspector (make-inspector))
(define (make-empty-stack i) (list (make-stack-frame i #f #f #f)))
;; The table is a vector that maps each state to a hash-table that maps a
;; terminal symbol to either an accept, shift, reduce, or goto structure.
; We encode the structures according to the runtime-action data definition in
;; parser-actions.rkt
(define (parser-body debug? err starts ends table all-term-syms actions src-pos)
(local ((define extract
(if src-pos
extract-src-pos
extract-no-src-pos))
(define (fix-error stack tok val start-pos end-pos get-token)
(when debug? (pretty-print stack))
(local ((define (remove-input tok val start-pos end-pos)
(if (memq tok ends)
(raise-read-error "parser: Cannot continue after error"
#f #f #f #f #f)
(let ((a (find-action stack tok val start-pos end-pos)))
(cond
((runtime-shift? a)
;; (printf "shift:~a\n" (runtime-shift-state a))
(cons (make-stack-frame (runtime-shift-state a)
val
start-pos
end-pos)
stack))
(else
;; (printf "discard input:~a\n" tok)
(let-values (((tok val start-pos end-pos)
(extract (get-token))))
(remove-input tok val start-pos end-pos))))))))
(let remove-states ()
(let ((a (find-action stack 'error #f start-pos end-pos)))
(cond
((runtime-shift? a)
;; (printf "shift:~a\n" (runtime-shift-state a))
(set! stack
(cons
(make-stack-frame (runtime-shift-state a)
#f
start-pos
end-pos)
stack))
(remove-input tok val start-pos end-pos))
(else
;; (printf "discard state:~a\n" (car stack))
(cond
((< (length stack) 2)
(raise-read-error "parser: Cannot continue after error"
#f #f #f #f #f))
(else
(set! stack (cdr stack))
(remove-states)))))))))
(define (find-action stack tok val start-pos end-pos)
(unless (hash-ref all-term-syms
tok
#f)
(if src-pos
(err #f tok val start-pos end-pos)
(err #f tok val))
(raise-read-error (format "parser: got token of unknown type ~a" tok)
#f #f #f #f #f))
(hash-ref (vector-ref table (stack-frame-state (car stack)))
tok
#f))
(define (make-parser start-number)
(lambda (get-token)
(unless (and (procedure? get-token)
(procedure-arity-includes? get-token 0))
(error 'get-token "expected a nullary procedure, got ~e" get-token))
(let parsing-loop ((stack (make-empty-stack start-number))
(ip (get-token)))
(let-values (((tok val start-pos end-pos)
(extract ip)))
(let ((action (find-action stack tok val start-pos end-pos)))
(cond
((runtime-shift? action)
;; (printf "shift:~a\n" (runtime-shift-state action))
(parsing-loop (cons (make-stack-frame (runtime-shift-state action)
val
start-pos
end-pos)
stack)
(get-token)))
((runtime-reduce? action)
;; (printf "reduce:~a\n" (runtime-reduce-prod-num action))
(let-values (((new-stack args)
(reduce-stack stack
(runtime-reduce-rhs-length action)
null
src-pos)))
(let ((goto
(runtime-goto-state
(hash-ref
(vector-ref table (stack-frame-state (car new-stack)))
(runtime-reduce-lhs action)))))
(parsing-loop
(cons
(if src-pos
(make-stack-frame
goto
(apply (vector-ref actions (runtime-reduce-prod-num action)) args)
(if (null? args) start-pos (cadr args))
(if (null? args)
end-pos
(list-ref args (- (* (runtime-reduce-rhs-length action) 3) 1))))
(make-stack-frame
goto
(apply (vector-ref actions (runtime-reduce-prod-num action)) args)
#f
#f))
new-stack)
ip))))
((runtime-accept? action)
;; (printf "accept\n")
(stack-frame-value (car stack)))
(else
(if src-pos
(err #t tok val start-pos end-pos)
(err #t tok val))
(parsing-loop (fix-error stack tok val start-pos end-pos get-token)
(get-token))))))))))
(cond
((null? (cdr starts)) (make-parser 0))
(else
(let loop ((l starts)
(i 0))
(cond
((null? l) null)
(else (cons (make-parser i) (loop (cdr l) (add1 i))))))))))

0
br-parser-tools/LICENSE.txt → parser-tools/LICENSE.txt
Unescape Escape View File

12
parser-tools/info.rkt
Unescape Escape View File

@ -0,0 +1,12 @@
#lang info
(define collection 'multi)
(define deps '("parser-tools-lib"
"parser-tools-doc"))
(define implies '("parser-tools-lib"
"parser-tools-doc"))
(define pkg-desc "Lex- and Yacc-style parsing tools")
(define pkg-authors '(mflatt))
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