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fix bugs in lookbehind matching #3

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fix bugs in lookbehind matching #3

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20 changes: 15 additions & 5 deletions pregexp-test.scm
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Original file line number Diff line number Diff line change
Expand Up @@ -248,12 +248,22 @@
((27 . 31))

(pregexp-match-positions "(?<=grey)hound"
"the hound in the picture is not a greyhound")
((38 . 43))

"\nthe hound in the picture is not a greyhound")
((39 . 44))

(pregexp-match-positions "(?<!grey)hound"
"\nthe greyhound in the picture is not a hound")
((39 . 44))

(pregexp-match-positions "(?<=grey)hound"
"greyhound"
4)
#f

(pregexp-match-positions "(?<!grey)hound"
"the greyhound in the picture is not a hound")
((38 . 43))
"greyhound"
4)
((4 . 9))

)

Expand Down
39 changes: 20 additions & 19 deletions pregexp.scm
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -439,18 +439,15 @@
'()))))

(define pregexp-match-positions-aux
(lambda (re s sn start n i)
(lambda (re s start n i)
(let ((identity (lambda (x) x))
(backrefs (pregexp-make-backref-list re))
(case-sensitive? #t))
(let sub ((re re) (i i) (sk identity) (fk (lambda () #f)))
;(printf "sub ~s ~s\n" i re)
(cond ((eqv? re ':bos)
;(if (= i 0) (sk i) (fk))
(if (= i start) (sk i) (fk))
)
((eqv? re ':eos)
;(if (>= i sn) (sk i) (fk))
(if (>= i n) (sk i) (fk))
)
((eqv? re ':empty)
Expand All @@ -464,7 +461,6 @@
(fk)
(sk i)))
((and (char? re) (< i n))
;(printf "bingo\n")
(if ((if case-sensitive? char=? char-ci=?)
(string-ref s i) re)
(sk (+ i 1)) (fk)))
Expand Down Expand Up @@ -539,22 +535,28 @@
identity (lambda () #f))))
(if found-it? (fk) (sk i))))
((:lookbehind)
(let ((n-actual n) (sn-actual sn))
(set! n i) (set! sn i)
(let ((n-actual n) (inner (cadr re)))
(set! n i)
(let ((found-it?
(sub (list ':seq '(:between #f 0 #f :any)
(cadr re) ':eos) 0
identity (lambda () #f))))
(set! n n-actual) (set! sn sn-actual)
(let loup-behind ((i i))
(sub inner i
(lambda (i) (= i n))
(lambda ()
(and (> i start)
(loup-behind (- i 1))))))))
(set! n n-actual)
(if found-it? (sk i) (fk)))))
((:neg-lookbehind)
(let ((n-actual n) (sn-actual sn))
(set! n i) (set! sn i)
(let ((n-actual n) (inner (cadr re)))
(set! n i)
(let ((found-it?
(sub (list ':seq '(:between #f 0 #f :any)
(cadr re) ':eos) 0
identity (lambda () #f))))
(set! n n-actual) (set! sn sn-actual)
(let loup-behind ((i i))
(sub inner i
(lambda (i) (= i n))
(lambda ()
(and (> i start)
(loup-behind (- i 1))))))))
(set! n n-actual)
(if found-it? (fk) (sk i)))))
((:no-backtrack)
(let ((found-it? (sub (cadr re) i
Expand Down Expand Up @@ -614,7 +616,6 @@
(else (pregexp-error 'pregexp-match-positions-aux))))
((>= i n) (fk))
(else (pregexp-error 'pregexp-match-positions-aux))))
;(printf "done\n")
(let ((backrefs (map cdr backrefs)))
(and (car backrefs) backrefs)))))

Expand Down Expand Up @@ -666,7 +667,7 @@
(let loop ((i start))
(and (<= i end)
(or (pregexp-match-positions-aux
pat str str-len start end i)
pat str start end i)
(loop (+ i 1))))))))

(define pregexp-match
Expand Down