diff --git a/collects/parser-tools/lex.ss b/collects/parser-tools/lex.ss index c1ca19e..70dedb7 100644 --- a/collects/parser-tools/lex.ss +++ b/collects/parser-tools/lex.ss @@ -3,227 +3,140 @@ ;; 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" + (require-for-syntax "private-lex/util.ss" "private-lex/actions.ss" - "private-lex/front.ss" - "private-lex/unicode-chars.ss") + "private-lex/front.ss") - (require (lib "stxparam.ss") - (lib "readerr.ss" "syntax") + (require (lib "readerr.ss" "syntax") + (lib "cffi.ss" "compiler") "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) + (provide lexer lexer-src-pos define-lex-abbrev define-lex-abbrevs + get-position position-offset position-line position-col position? + define-tokens define-empty-tokens token-name token-value token? file-path) - ;; 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))) - #;(when (vector-ref action-names start) - (raise-syntax-error #f "accepts the empty string" 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?)) - (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 file-path (make-parameter #f)) + + (define-syntaxes (lexer lexer-src-pos) + (let ((build-lexer + (lambda (wrap?) + (lambda (stx) + (syntax-case stx () + ((_) + (raise-syntax-error #f "empty lexer is not allowed" stx)) + ((_ re-act ...) + (begin + (for-each + (lambda (x) + (syntax-case x () + ((re act) (void)) + (_ (raise-syntax-error 'lexer + "expects regular expression / action pairs" + 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 exception))) + (spec-comment-act + (get-special-action spec/re-act-lst 'special-comment #'#f)) + (re-act-lst + (filter-out-specials spec/re-act-lst + '(special special-comment special-error eof)))) + (let-values (((trans start actions no-look) + (build-lexer re-act-lst))) + (with-syntax ((start-state-stx start) + (trans-table-stx trans) + (no-lookahead-stx no-look) + (actions-stx `(vector ,@(map (lambda (a) + (if a (wrap-action a 'lexeme #'here a) #f)) + (vector->list actions)))) + (spec-act-stx + (wrap-action spec-act 'special #'here spec-act)) + (spec-error-act-stx + (wrap-action spec-error-act 'exception #'here spec-error-act)) + (has-comment-act?-stx (if (syntax-e spec-comment-act) #t #f)) + (spec-comment-act-stx + (wrap-action spec-comment-act (gensym) #'here spec-comment-act)) + (eof-act-stx + (wrap-action eof-act 'lexeme #'here eof-act)) + (wrap? wrap?)) + (syntax + (lexer-body start-state-stx + trans-table-stx + actions-stx + no-lookahead-stx + spec-act-stx + spec-error-act-stx + has-comment-act?-stx + spec-comment-act-stx + eof-act-stx + wrap?)))))))))))) + (values + (build-lexer #f) + (build-lexer #t)))) (define-syntax (define-lex-abbrev stx) (syntax-case stx () ((_ name re) - (identifier? (syntax name)) - (syntax/loc stx + (syntax (define-syntax name (make-lex-abbrev (quote-syntax re))))) (_ (raise-syntax-error #f - "form should be (define-lex-abbrev name re)" + "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))))))) + (let* ((abbrev (syntax->list (syntax (x ...)))) + (r (map (lambda (a) + (syntax-case a () + ((name re) + (identifier? (syntax name)) + (syntax (define-lex-abbrev name re))) + (_ (raise-syntax-error + 'Lexer-abbreviation + "Form should be (identifier value)" + a)))) + abbrev))) + (datum->syntax-object + #'here + (cons 'begin r) + stx))) (_ (raise-syntax-error #f - "form should be (define-lex-trans name transformer)" + "Form should be (define-lex-abbrevs (name re) ...)" 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) + has-special-comment-action? special-comment-action eof-action wrap?) (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))) - ;(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)) + ((eq? 'special first-char) (let* ((comment? #f) (error? #f) - (spec (with-handlers ((special-comment? + (spec (with-handlers ((exn:special-comment? (lambda (x) (set! comment? #t))) - (exn:fail? + (not-break-exn? (lambda (ex) (set! error? #t) ex))) (read-char-or-special ip)))) (cond @@ -234,7 +147,9 @@ (comment? special-comment-action) (error? special-error-action) (else special-action)) - spec))))) + spec wrap?))))) + ((eof-object? first-char) + (do-match ip first-pos eof-action (read-char-or-special ip) wrap?)) (else (let lexer-loop ( ;; current-state @@ -245,56 +160,47 @@ ;; 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) + (length 1) ;; how many characters are in the longest match (longest-match-length 0)) (let ((next-state (cond ((eof-object? char) #f) - ((not (char? char)) #f) - (else (get-next-state (char->integer char) - (vector-ref trans-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-chars longest-match-action)) + 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-chars longest-match-length) - length-chars - (if act act longest-match-action)))) + (if act length longest-match-length) + length + (if act act longest-match-action) + wrap?))) (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) + (let ((act (vector-ref actions next-state))) (lexer-loop next-state - next-char + (peek-char-or-special ip length) (if act act longest-match-action) - next-length-bytes - (add1 length-chars) + (add1 length) (if act - length-chars + length longest-match-length))))))))))))) - (lambda (ip) - (unless (input-port? ip) - (raise-type-error - 'lexer - "input-port" - 0 - ip)) - (lexer ip)))) + lexer)) - (define (check-match lb first-pos longest-match-length length longest-match-action) + (define id (lambda (x) x)) + + (define (check-match lb first-pos longest-match-length length longest-match-action wrap?) (unless longest-match-action (let* ((match (read-string length lb)) (end-pos (get-position lb))) @@ -306,81 +212,23 @@ (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))) + (do-match lb first-pos longest-match-action match wrap?))) - (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 (do-match ip first-pos action value wrap?) + (let ((end-pos (get-position ip))) + (cond + (wrap? + (let/ec ret + (list (action first-pos end-pos value ret ip) + first-pos + end-pos))) + (else + (action first-pos end-pos value id ip))))) + (define-struct position (offset line col)) (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) - )