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original commit: 17bf91debb00e110dea94115149f04ab20dc8d1e
tokens
Scott Owens 20 years ago
parent 6e0524b098
commit cb57eb49ea
1 changed files with 10 additions and 25 deletions
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35
collects/parser-tools/lex.ss
Unescape Escape View File

@ -71,11 +71,9 @@
(get-special-action spec/re-act-lst #'eof #''eof)) (get-special-action spec/re-act-lst #'eof #''eof))
(spec-act (spec-act
(get-special-action spec/re-act-lst #'special #'(void))) (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 (spec-comment-act
(get-special-action spec/re-act-lst #'special-comment #'#f)) (get-special-action spec/re-act-lst #'special-comment #'#f))
(ids (list #'special #'special-comment #'special-error #'eof)) (ids (list #'special #'special-comment #'eof))
(re-act-lst (re-act-lst
(filter (filter
(lambda (spec/re-act) (lambda (spec/re-act)
@ -123,8 +121,6 @@
((act-name ...) (vector->list action-names)) ((act-name ...) (vector->list action-names))
(spec-act-stx (spec-act-stx
(wrap-action spec-act src-pos?)) (wrap-action spec-act src-pos?))
(spec-error-act-stx
(wrap-action spec-error-act src-pos?))
(has-comment-act?-stx (has-comment-act?-stx
(if (syntax-e spec-comment-act) #t #f)) (if (syntax-e spec-comment-act) #t #f))
(spec-comment-act-stx (spec-comment-act-stx
@ -138,7 +134,6 @@
(vector act-name ...) (vector act-name ...)
no-lookahead-stx no-lookahead-stx
spec-act-stx spec-act-stx
spec-error-act-stx
has-comment-act?-stx has-comment-act?-stx
spec-comment-act-stx spec-comment-act-stx
eof-act-stx))) eof-act-stx)))
@ -220,8 +215,7 @@
(get-next-state-helper char 0 (vector-length table) table) (get-next-state-helper char 0 (vector-length table) table)
#f)) #f))
(define (lexer-body start-state trans-table actions no-lookahead (define (lexer-body start-state trans-table actions no-lookahead special-action
special-action special-error-action
has-special-comment-action? special-comment-action eof-action) has-special-comment-action? special-comment-action eof-action)
(letrec ((lexer (letrec ((lexer
(lambda (ip) (lambda (ip)
@ -231,23 +225,15 @@
(cond (cond
((eof-object? first-char) ((eof-object? first-char)
(do-match ip first-pos eof-action (read-char-or-special ip))) (do-match ip first-pos eof-action (read-char-or-special ip)))
((not (char? first-char)) ((special-comment? first-char)
(let* ((comment? #f) (read-char-or-special ip)
(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 (cond
((and comment? (not has-special-comment-action?)) (has-special-comment-action?
(lexer ip)) (do-match ip first-pos special-comment-action #f))
(else (else (lexer ip))))
(do-match ip first-pos (cond ((not (char? first-char))
(comment? special-comment-action) (let ((spec (read-char-or-special ip)))
(error? special-error-action) (do-match ip first-pos special-action (read-char-or-special ip))))
(else special-action))
spec)))))
(else (else
(let lexer-loop ( (let lexer-loop (
;; current-state ;; current-state
@ -267,7 +253,6 @@
(longest-match-length 0)) (longest-match-length 0))
(let ((next-state (let ((next-state
(cond (cond
((eof-object? char) #f)
((not (char? char)) #f) ((not (char? char)) #f)
(else (get-next-state (char->integer char) (else (get-next-state (char->integer char)
(vector-ref trans-table state)))))) (vector-ref trans-table state))))))

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