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.
375 lines
16 KiB
Scheme
375 lines
16 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)
|
|
|
|
(define file-path (make-parameter #f))
|
|
|
|
;; wrap-action: syntax-object -> syntax-object
|
|
(define-for-syntax (wrap-action action)
|
|
(with-syntax ((action-stx action))
|
|
(syntax/loc action
|
|
(lambda (start-pos-p end-pos-p lexeme-p return-without-pos-p input-port-p)
|
|
(syntax-parameterize
|
|
((start-pos (lambda (x) #'start-pos-p))
|
|
(end-pos (lambda (x) #'end-pos-p))
|
|
(lexeme (lambda (x) #'lexeme-p))
|
|
(return-without-pos (lambda (x) #'return-without-pos-p))
|
|
(input-port (lambda (x) #'input-port-p)))
|
|
action-stx)))))
|
|
|
|
(define-for-syntax (make-lexer-trans wrap?)
|
|
(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)))
|
|
(let-values (((trans start actions no-look disappeared-uses)
|
|
(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) #f))
|
|
(vector->list actions))))
|
|
(spec-act-stx
|
|
(wrap-action spec-act))
|
|
(spec-error-act-stx
|
|
(wrap-action spec-error-act))
|
|
(has-comment-act?-stx
|
|
(if (syntax-e spec-comment-act) #t #f))
|
|
(spec-comment-act-stx
|
|
(wrap-action spec-comment-act))
|
|
(eof-act-stx (wrap-action eof-act))
|
|
(wrap? wrap?))
|
|
(syntax-property
|
|
(syntax/loc stx
|
|
(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?))
|
|
'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 (make-lex-trans #,body))))
|
|
(_
|
|
(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 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) wrap?))
|
|
((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 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-bytes (char-utf-8-length first-char))
|
|
(length-chars 1)
|
|
;; how many characters are in the longest match
|
|
(longest-match-length 1))
|
|
;; (printf "(peek-char-or-special port ~e) = ~e~n" (sub1 length-bytes) char)
|
|
(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 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)
|
|
wrap?)))
|
|
(else
|
|
(let ((act (vector-ref actions next-state)))
|
|
(lexer-loop next-state
|
|
(peek-char-or-special ip length-bytes)
|
|
(if act
|
|
act
|
|
longest-match-action)
|
|
(+ (char-utf-8-length char) length-bytes)
|
|
(add1 length-chars)
|
|
(if act
|
|
length-chars
|
|
longest-match-length)))))))))))))
|
|
lexer))
|
|
|
|
(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)))
|
|
(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 wrap?)))
|
|
|
|
|
|
(define (do-match ip first-pos action value wrap?)
|
|
(let ((end-pos (get-position ip)))
|
|
(cond
|
|
(wrap?
|
|
(let/ec ret
|
|
(make-position-token (action first-pos end-pos value ret ip)
|
|
first-pos
|
|
end-pos)))
|
|
(else
|
|
(action first-pos end-pos value id 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)
|
|
|
|
)
|