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original commit: 176176d30261069544a413a4a2385412b777223e
tokens
Scott Owens 20 years ago
parent fddf5e115f
commit 519b6f80a3
2 changed files with 140 additions and 5 deletions
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103
collects/parser-tools/lex.ss
Unescape Escape View File

@ -115,8 +115,7 @@
#f
"Form should be (define-lex-abbrevs (name re) ...)"
stx))))
#;
(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?)
@ -197,6 +196,106 @@
length
longest-match-length)))))))))))))
lexer))
(define (get-next-state-helper char min max table)
(if (>= min max)
#f
(let* ((try (quotient (+ min max) 2))
(el (vector-ref table try))
(range (car el))
(r1 (car range))
(r2 (cdr range)))
(cond
((and (>= char r1) (<= char r2)) (cdr el))
((< 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)))
(cond
((eq? 'special first-char)
(let* ((comment? #f)
(error? #f)
(spec (with-handlers ((exn:special-comment?
(lambda (x) (set! comment? #t)))
(not-break-exn?
(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?)))))
((eof-object? first-char)
(do-match ip first-pos eof-action (read-char-or-special ip) 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) #f)
((eq? char 'special) #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 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))

42
collects/parser-tools/private-lex/front.ss
Unescape Escape View File

@ -1,5 +1,6 @@
(module front mzscheme
(require (prefix is: (lib "integer-set.ss"))
(lib "list.ss")
"util.ss"
"stx.ss"
"re.ss"
@ -18,10 +19,31 @@
;; - (vector-of (union #f nat))
;; - (vector-of (vector-of (cons (cons nat nat) nat)))
(define loc:integer-set-contents is:integer-set-contents)
;; dfa->1d-table : dfa -> (same as build-lexer)
; (define (dfa->1d-table dfa)
; (let (
(define (dfa->1d-table dfa)
(let ((state-table (make-vector (dfa-num-states dfa) #f)))
(for-each (lambda (trans)
(let* ((from-state (car trans))
(all-chars/to (cdr trans))
(flat-all-chars/to
(mergesort
(apply append
(map (lambda (chars/to)
(let ((char-ranges (loc:integer-set-contents (car chars/to)))
(to (cdr chars/to)))
(map (lambda (char-range)
(cons char-range to))
char-ranges)))
all-chars/to))
(lambda (a b)
(< (caar a) (caar b))))))
(vector-set! state-table from-state (list->vector flat-all-chars/to))))
(dfa-transitions dfa))
state-table))
(define loc:foldr is:foldr)
;; dfa->2d-table : dfa -> (same as build-lexer)
@ -76,6 +98,11 @@
(d2 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3))))))
(d3 (make-dfa 4 1 (list (cons 2 2) (cons 3 3))
(list (cons 1 (list (cons (is:make-range 100 200) 0)
(cons (is:make-range 49 50) 1)
(cons (is:make-range 51) 2)))
(cons 2 (list (cons (is:make-range 49) 3)))))))
((dfa->2d-table d1) (make-vector 256 #f))
((dfa->2d-table d2) (let ((v (make-vector 1024 #f)))
@ -84,6 +111,15 @@
(vector-set! v 307 2)
(vector-set! v 561 3)
v))
((dfa->1d-table d1) (make-vector 1 #f))
((dfa->1d-table d2) #(#f
#(((49 . 50) . 1) ((51 . 51) . 2))
#(((49 . 49) . 3))
#f))
((dfa->1d-table d3) #(#f
#(((49 . 50) . 1) ((51 . 51) . 2) ((100 . 200) . 0))
#(((49 . 49) . 3))
#f))
((dfa->actions d1) (vector #f))
((dfa->actions d2) (vector #f #f 2 3))
((dfa->no-look d1) (vector #t))
@ -107,5 +143,5 @@
(dfa (time (build-dfa re-acts cache))))
;(print-dfa dfa)
;(printf "states: ~a~n" (dfa-num-states dfa))
(values (time (dfa->2d-table dfa)) (dfa-start-state dfa) (dfa->actions dfa) (dfa->no-look dfa))))
(values (time (dfa->1d-table dfa)) (dfa-start-state dfa) (dfa->actions dfa) (dfa->no-look dfa))))
)

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