You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
385 lines
17 KiB
Scheme
385 lines
17 KiB
Scheme
(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 doc.txt.
|
|
|
|
(require-for-syntax (lib "list.ss")
|
|
(lib "stx.ss" "syntax")
|
|
(lib "define.ss" "syntax")
|
|
(lib "boundmap.ss" "syntax")
|
|
"private-lex/util.ss"
|
|
"private-lex/actions.ss"
|
|
"private-lex/front.ss"
|
|
"private-lex/unicode-chars.ss")
|
|
|
|
(require (lib "stxparam.ss")
|
|
(lib "readerr.ss" "syntax")
|
|
"private-lex/token.ss")
|
|
|
|
(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 ()
|
|
((_)
|
|
(raise-syntax-error #f "accepts the empty string" 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-error-act
|
|
(get-special-action spec/re-act-lst #'special-error #'(raise lexeme)))
|
|
(spec-comment-act
|
|
(get-special-action spec/re-act-lst #'special-comment #'#f))
|
|
(ids (list #'special #'special-comment #'special-error #'eof))
|
|
(re-act-lst
|
|
(filter
|
|
(lambda (spec/re-act)
|
|
(syntax-case spec/re-act ()
|
|
(((special) act)
|
|
(not (ormap
|
|
(lambda (x)
|
|
(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)))
|
|
(let-values (((trans start action-names no-look disappeared-uses)
|
|
(build-lexer re-actname-lst)))
|
|
(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?))
|
|
(spec-error-act-stx
|
|
(wrap-action spec-error-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] ...)
|
|
(lexer-body start-state-stx
|
|
trans-table-stx
|
|
(vector act-name ...)
|
|
no-lookahead-stx
|
|
spec-act-stx
|
|
spec-error-act-stx
|
|
has-comment-act?-stx
|
|
spec-comment-act-stx
|
|
eof-act-stx)))
|
|
'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 (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 ((certifier (syntax-local-certifier)))
|
|
(make-lex-trans (lambda (stx)
|
|
(certifier (#,body stx) 'a)))))))
|
|
(_
|
|
(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 special-error-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)))
|
|
((not (char? first-char))
|
|
(let* ((comment? #f)
|
|
(error? #f)
|
|
(spec (with-handlers ((special-comment?
|
|
(lambda (x) (set! comment? #t)))
|
|
(exn:fail?
|
|
(lambda (ex) (set! error? #t) ex)))
|
|
(read-char-or-special ip))))
|
|
(cond
|
|
((and comment? (not has-special-comment-action?))
|
|
(lexer ip))
|
|
(else
|
|
(do-match ip first-pos (cond
|
|
(comment? special-comment-action)
|
|
(error? special-error-action)
|
|
(else special-action))
|
|
spec)))))
|
|
(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 preceed 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 1))
|
|
(let ((next-state
|
|
(cond
|
|
((eof-object? char) #f)
|
|
((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-type-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)
|
|
|
|
)
|