From 08792e684e6733310f0ac5dd28eb637d73332952 Mon Sep 17 00:00:00 2001 From: Scott Owens Date: Sat, 18 Oct 2003 02:26:22 +0000 Subject: [PATCH] *** empty log message *** original commit: 17e9ac305563e736049bef0b956ca048284a8117 --- collects/parser-tools/lex.ss | 156 +++++++++++++++++++---------------- 1 file changed, 84 insertions(+), 72 deletions(-) diff --git a/collects/parser-tools/lex.ss b/collects/parser-tools/lex.ss index bd91a76..4336f7e 100644 --- a/collects/parser-tools/lex.ss +++ b/collects/parser-tools/lex.ss @@ -60,10 +60,17 @@ "expects regular expression / action pairs" x)))) (syntax->list (syntax (re-act ...)))) - (let* ((spec/re-act-lst (syntax->list (syntax (re-act ...)))) - (spec-act (get-special-action spec/re-act-lst 'special #'here)) - (spec-comment-act (get-special-action spec/re-act-lst 'special-comment #'here)) - (re-act-lst (filter-out-specials spec/re-act-lst '(special special-comment)))) + (let* ((error-continue-arg (gensym)) + (spec/re-act-lst + (syntax->list (syntax (re-act ...)))) + (spec-act + (get-special-action spec/re-act-lst 'special #'(void))) + (spec-comment-act + (get-special-action spec/re-act-lst 'special-comment + #`(#,error-continue-arg input-port))) + (re-act-lst + (filter-out-specials spec/re-act-lst + '(special special-comment special-error)))) (let ((table (generate-table re-act-lst stx))) (with-syntax ((start-state-stx (table-start table)) (trans-table-stx (table-trans table)) @@ -79,7 +86,8 @@ (spec-comment-act-stx (datum->syntax-object spec-comment-act - `(lambda (start-pos end-pos ,(gensym) return-without-pos input-port) + `(lambda (start-pos end-pos ,error-continue-arg + return-without-pos input-port) ,spec-comment-act) spec-comment-act)) (wrap? wrap?)) @@ -143,76 +151,80 @@ (let ((first-pos (get-position ip))) (let-values (((longest-match-length length longest-match-action) (lexer ip peek-string))) - (check-match ip first-pos longest-match-length length (vector-ref actions longest-match-action) wrap?))))) + (check-match ip first-pos longest-match-length length + (vector-ref actions longest-match-action) wrap?))))) (define (lexer-body start-state trans-table eof-table actions no-lookahead special-action special-comment-action wrap?) - (lambda (ip) - (unless (input-port? ip) - (raise-type-error - 'lexer - "input-port" - 0 - ip)) - (let ((first-pos (get-position ip)) - (first-char (peek-char-or-special ip 0))) - (cond - ((eq? 'special first-char) - (let* ((comment? #f) - (spec (with-handlers ((exn:special-comment? - (lambda (x) (set! comment? #t) #f))) - (read-char-or-special ip)))) - (do-match ip first-pos (if comment? - special-comment-action - special-action) - spec wrap?))) - (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 characters have been read - ;; including the one just read - (length 1) - ;; how many characters are in the longest match - (longest-match-length 1)) - (let ((next-state - (cond - ((eof-object? char) - (vector-ref eof-table state)) - ((eq? char 'special) - #f) - (else - (vector-ref - trans-table - (+ (char->integer char) (* 256 state))))))) - (cond - ((not next-state) - (check-match ip first-pos longest-match-length length longest-match-action wrap?)) - ((vector-ref no-lookahead next-state) - (let ((act (vector-ref actions next-state))) - (check-match ip - first-pos - (if act length longest-match-length) - length - (if act act longest-match-action) - wrap?))) - (else - (let ((act (vector-ref actions next-state))) - (lexer-loop next-state - (peek-char-or-special ip length) - (if act - act - longest-match-action) - (add1 length) - (if act - length - longest-match-length)))))))))))) + (letrec ((lexer + (lambda (ip) + (unless (input-port? ip) + (raise-type-error + 'lexer + "input-port" + 0 + ip)) + (let ((first-pos (get-position ip)) + (first-char (peek-char-or-special ip 0))) + (cond + ((eq? 'special first-char) + (let* ((comment? #f) + (spec (with-handlers ((exn:special-comment? + (lambda (x) (set! comment? #t) lexer))) + (read-char-or-special ip)))) + (do-match ip first-pos (if comment? + special-comment-action + special-action) + spec wrap?))) + (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 characters have been read + ;; including the one just read + (length 1) + ;; how many characters are in the longest match + (longest-match-length 1)) + (let ((next-state + (cond + ((eof-object? char) + (vector-ref eof-table state)) + ((eq? char 'special) + #f) + (else + (vector-ref + trans-table + (+ (char->integer char) (* 256 state))))))) + (cond + ((not next-state) + (check-match ip first-pos longest-match-length + length longest-match-action wrap?)) + ((vector-ref no-lookahead next-state) + (let ((act (vector-ref actions next-state))) + (check-match ip + first-pos + (if act length longest-match-length) + length + (if act act longest-match-action) + wrap?))) + (else + (let ((act (vector-ref actions next-state))) + (lexer-loop next-state + (peek-char-or-special ip length) + (if act + act + longest-match-action) + (add1 length) + (if act + length + longest-match-length))))))))))))) + lexer)) (define id (lambda (x) x))