rebase on fork of parser-tools

pull/5/head
Matthew Butterick 6 years ago
parent 3e71cfa350
commit 9b8e0f96c8

@ -2,14 +2,14 @@
@(require scribble/manual scribble/struct scribble/xref scribble/bnf
(for-label scheme/base
scheme/contract
parser-tools/lex
(prefix-in : parser-tools/lex-sre)
parser-tools/yacc
parser-tools/cfg-parser))
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre)
br-parser-tools/yacc
br-parser-tools/cfg-parser))
@title{Parser Tools: @exec{lex} and @exec{yacc}-style Parsing}
@title{Parser Tools: @exec{lex} and @exec{yacc}-style Parsing (Beautiful Racket edition)}
@author["Scott Owens"]
@author["Scott Owens (99%)" "Matthew Butterick (1%)"]
This documentation assumes familiarity with @exec{lex} and @exec{yacc}
style lexer and parser generators.
@ -24,7 +24,7 @@ style lexer and parser generators.
@section-index["scanning"]
@section-index["scanner"]
@defmodule[parser-tools/lex]
@defmodule[br-parser-tools/lex]
@; ----------------------------------------
@ -59,7 +59,7 @@ style lexer and parser generators.
@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{parser-tools} collection contain
of the @filepath{br-parser-tools} collection contain
simpler example lexers.}
An @racket[re] is matched as follows:
@ -67,7 +67,7 @@ style lexer and parser generators.
@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[parser-tools/lex-sre].}
like @racketmodname[br-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]
@ -92,15 +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[parser-tools/lex-sre] supplies operators from Olin
Shivers's SREs, and @racketmodname[parser-tools/lex-plt-v200] supplies
@racketmodname[br-parser-tools/lex-sre] supplies operators from Olin
Shivers's SREs, and @racketmodname[br-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 : parser-tools/lex-sre))
(require (prefix-in : br-parser-tools/lex-sre))
]
The suggested prefix is @racket[:], so that @racket[:*] and
@ -167,14 +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)] 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
@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
information. For example:
@racketblock[
(define get-token
(lexer-src-pos
(lexer-srcloc
...
((comment) (get-token input-port))
...))
@ -182,12 +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-pos (get-token input-port)))]
@racket[((comment) (return-without-srcloc (get-token input-port)))]
will cause the value of the recursive call to be returned without
wrapping position around it.}
]
The lexer raises an exception @racket[(exn:read)] if none of the
The lexer raises an @racket[exn:fail:read] exception 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
@ -248,12 +248,21 @@ 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
@ -276,12 +285,21 @@ 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].}
@; ----------------------------------------
@ -340,14 +358,14 @@ characters, @racket[char-lower-case?] characters, etc.}
@subsection{Lexer SRE Operators}
@defmodule[parser-tools/lex-sre]
@defmodule[br-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 parser-tools/lex-sre))
(require (for-label br-parser-tools/lex-sre))
@defform[(* re ...)]{
@ -416,16 +434,16 @@ characters.}
@subsection{Lexer Legacy Operators}
@defmodule[parser-tools/lex-plt-v200]
@defmodule[br-parser-tools/lex-plt-v200]
@(define-syntax-rule (lex-v200-doc)
(...
(begin
(require (for-label parser-tools/lex-plt-v200))
(require (for-label br-parser-tools/lex-plt-v200))
@t{The @racketmodname[parser-tools/lex-plt-v200] module re-exports
@t{The @racketmodname[br-parser-tools/lex-plt-v200] module re-exports
@racket[*], @racket[+], @racket[?], and @racket[&] from
@racketmodname[parser-tools/lex-sre]. It also re-exports
@racketmodname[br-parser-tools/lex-sre]. It also re-exports
@racket[:or] as @racket[:], @racket[::] as @racket[|@|], @racket[:~]
as @racket[^], and @racket[:/] as @racket[-].}
@ -446,7 +464,7 @@ 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[parser-tools/parser], but tokens may not
a parser generated by @racket[br-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 ...))]{
@ -492,7 +510,7 @@ be the right choice when using @racket[lexer] in other situations.
@section-index["yacc"]
@defmodule[parser-tools/yacc]
@defmodule[br-parser-tools/yacc]
@defform/subs[#:literals (grammar tokens start end precs src-pos
suppress debug yacc-output prec)
@ -691,9 +709,9 @@ be the right choice when using @racket[lexer] in other situations.
@section-index["cfg-parser"]
@defmodule[parser-tools/cfg-parser]{The @racketmodname[parser-tools/cfg-parser]
@defmodule[br-parser-tools/cfg-parser]{The @racketmodname[br-parser-tools/cfg-parser]
library provides a parser generator that is an alternative to that of
@racketmodname[parser-tools/yacc].}
@racketmodname[br-parser-tools/yacc].}
@defform/subs[#:literals (grammar tokens start end precs src-pos
suppress debug yacc-output prec)
@ -710,7 +728,7 @@ 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[parser-tools/yacc], with
grammars. Its interface is a subset of @racketmodname[br-parser-tools/yacc], with
the following differences:
@itemize[
@ -730,7 +748,7 @@ library provides a parser generator that is an alternative to that of
@section{Converting @exec{yacc} or @exec{bison} Grammars}
@defmodule[parser-tools/yacc-to-scheme]
@defmodule[br-parser-tools/yacc-to-scheme]
@defproc[(trans [file path-string?]) any/c]{
@ -744,7 +762,7 @@ 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{parser-tools} collection.}
@filepath{br-parser-tools} collection.}
@; ----------------------------------------------------------------------

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

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

@ -1,5 +1,5 @@
#lang racket/base
;; This module implements a parser form like the parser-tools's
;; This module implements a parser form like the br-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 parser-tools's `parse' is used to transform tokens in the
;; The br-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 parser-tools/yacc
parser-tools/lex)
(require br-parser-tools/yacc
br-parser-tools/lex)
(require (for-syntax racket/base
syntax/boundmap
parser-tools/private-lex/token-syntax))
br-parser-tools/private-lex/token-syntax))
(provide cfg-parser)
@ -489,6 +489,12 @@
(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
;; (IIUC, the parser is multi-threaded, and this approach is not thread-safe)
;; so I see no alternative to the old standby of making them ludicrously unlikely
(define-for-syntax start-id-temp 'start_jihqolbbafscgxvsufnepvmxqipnxgmlpxukmdoqxqzmzgaogaftbkbyqjttwwfimifowdxfyekjiixdmtprfkcvfciraehoeuaz)
(define-for-syntax atok-id-temp 'atok_wrutdjgecmybyfipiwsgjlvsveryodlgassuzcargiuznzgdghrykfqfbwcjgzdhdoeqxcucmtjkuyucskzethozhqkasphdwbht)
(define-syntax (cfg-parser stx)
(syntax-case stx ()
[(_ clause ...)
@ -704,11 +710,17 @@
[(pos ...)
(if src-pos?
#'($1-start-pos $1-end-pos)
#'(#f #f))])
#`(grammar (start [() null]
[(atok start) (cons $1 $2)])
(atok [(tok) (make-tok 'tok-id 'tok $e pos ...)] ...)))
#`(start start)
#'(#f #f))]
;; rename `start` and `atok` to temp ids
;; so that "start" and "atok" can be used as literal string tokens in a grammar.
;; not sure why this works, but it passes all tests.
[%start start-id-temp]
[%atok atok-id-temp])
#`(grammar (%start [() null]
[(%atok %start) (cons $1 $2)])
(%atok [(tok) (make-tok 'tok-id 'tok $e pos ...)] ...)))
(with-syntax ([%start start-id-temp])
#`(start %start))
parser-clauses)))]
[(grammar . _)
(raise-syntax-error
@ -744,16 +756,10 @@
val
(next success-k fail-k 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
(call-error-proc #t
(error-proc #t
'no-tokens
#f
(make-position #f #f #f)
@ -766,7 +772,7 @@
(min (sub1 (length tok-list))
max-depth))])
(if error-proc
(call-error-proc #t
(error-proc #t
(tok-orig-name bad-tok)
(tok-val bad-tok)
(tok-start bad-tok)
@ -803,9 +809,8 @@
(module* test racket/base
(require (submod "..")
parser-tools/lex
br-parser-tools/lex
racket/block
racket/generator
rackunit)
;; Test: parsing regular expressions.
@ -855,60 +860,6 @@
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))))))))

@ -4,9 +4,9 @@
;; Import the parser and lexer generators.
(require parser-tools/yacc
parser-tools/lex
(prefix-in : parser-tools/lex-sre))
(require br-parser-tools/yacc
br-parser-tools/lex
(prefix-in : br-parser-tools/lex-sre))
(define-tokens value-tokens (NUM VAR FNCT))
(define-empty-tokens op-tokens (newline = OP CP + - * / ^ EOF NEG))

@ -4,9 +4,9 @@
(module read mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre)
parser-tools/yacc
(require br-parser-tools/lex
(prefix : br-parser-tools/lex-sre)
br-parser-tools/yacc
syntax/readerr)
(define-tokens data (DATUM))

@ -1,6 +1,6 @@
(module lex-plt-v200 mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre))
(require br-parser-tools/lex
(prefix : br-parser-tools/lex-sre))
(provide epsilon
~

@ -1,5 +1,5 @@
(module lex-sre mzscheme
(require parser-tools/lex)
(require br-parser-tools/lex)
(provide (rename sre-* *)
(rename sre-+ +)

@ -0,0 +1,369 @@
#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 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"
racket/base
racket/promise))
(require mzlib/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. 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-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)
(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 #'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 disappeared-uses) (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-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:
(λ (port) (proc port)))))
'disappeared-use disappeared-uses)))])))
(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)
(letrec ([lexer
(λ (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)))])))])))])
(λ (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 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)

@ -1,4 +1,4 @@
#lang scheme/base
#lang racket/base
(provide (all-defined-out))
(require syntax/stx)
@ -10,7 +10,7 @@
((null? rules) none)
(else
(syntax-case (car rules) ()
(((special) act)
[((special) ACT)
(and (identifier? #'special) (module-or-top-identifier=? (syntax special) which-special))
(syntax act))
(_ (get-special-action (cdr rules) which-special none))))))
#'ACT]
[_ (get-special-action (cdr rules) which-special none)]))))

@ -172,7 +172,7 @@
((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)
(eqv? (repeatR-high r) +inf.0)
(or (= 0 (repeatR-low r))
(= 1 (repeatR-low r))))
(build-repeat (* low (repeatR-low r))

@ -84,7 +84,7 @@
stx
(car arg-list)))
(unless (or (and (number? high) (exact? high) (integer? high) (>= high 0))
(eq? high +inf.0))
(eqv? high +inf.0))
(raise-syntax-error #f
"not a non-negative exact integer or +inf.0"
stx

@ -10,7 +10,8 @@
(rename token-name* token-name)
(rename token-value* token-value)
(struct position (offset line col))
(struct position-token (token start-pos end-pos)))
(struct position-token (token start-pos end-pos))
(struct srcloc-token (token srcloc)))
;; A token is either
@ -85,5 +86,7 @@
(define-struct position (offset line col) #f)
(define-struct position-token (token start-pos end-pos) #f)
(define-struct srcloc-token (token srcloc) #f)
)

@ -1,7 +1,7 @@
(module yacc-to-scheme mzscheme
(require parser-tools/lex
(prefix : parser-tools/lex-sre)
parser-tools/yacc
(require br-parser-tools/lex
(prefix : br-parser-tools/lex-sre)
br-parser-tools/yacc
syntax/readerr
mzlib/list)
(provide trans)

@ -0,0 +1,412 @@
#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-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))
(let ([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)
(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))))))))))

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

@ -0,0 +1,12 @@
#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))

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

@ -1,393 +0,0 @@
(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)
)

@ -1,396 +0,0 @@
#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))))))))))

@ -1,12 +0,0 @@
#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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