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Fix replace-regexp-in-string substring match data translation

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For certain patterns, re-matching the same regexp on the matched
substring does not produce correctly translated match data
(bug#15107 and bug#44861).

Using a new builtin function also improves performance since the
number of calls to string-match is halved.

Reported by Kevin Ryde and Shigeru Fukaya.

* lisp/subr.el (replace-regexp-in-string): Translate the match data
using match-data--translate instead of trusting a call to string-match
on the matched string to do the job.
* test/lisp/subr-tests.el (subr-replace-regexp-in-string):
Add test cases.
* src/search.c (Fmatch_data__translate): New internal function.
(syms_of_search): Register it as a subroutine.
This commit is contained in:
Mattias Engdegård 2020-11-25 15:32:08 +01:00
parent 0287c51768
commit 558b6dbca7
3 changed files with 26 additions and 5 deletions
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7
lisp/subr.el
View file

@ -4546,10 +4546,9 @@ and replace a sub-expression, e.g.
(when (= me mb) (setq me (min l (1+ mb))))
;; Generate a replacement for the matched substring.
;; Operate on only the substring to minimize string consing.
;; Set up match data for the substring for replacement;
;; presumably this is likely to be faster than munging the
;; match data directly in Lisp.
(string-match regexp (setq str (substring string mb me)))
;; Translate the match data so that it applies to the matched substring.
(match-data--translate (- mb))
(setq str (substring string mb me))
(setq matches
(cons (replace-match (if (stringp rep)
rep

18
src/search.c
View file

@ -3031,6 +3031,23 @@ If optional arg RESEAT is non-nil, make markers on LIST point nowhere. */)
return Qnil;
}
DEFUN ("match-data--translate", Fmatch_data__translate, Smatch_data__translate,
1, 1, 0,
doc: /* Add N to all string positions in the match data. Internal. */)
(Lisp_Object n)
{
CHECK_FIXNUM (n);
EMACS_INT delta = XFIXNUM (n);
if (EQ (last_thing_searched, Qt)) /* String match data only. */
for (ptrdiff_t i = 0; i < search_regs.num_regs; i++)
if (search_regs.start[i] >= 0)
{
search_regs.start[i] = max (0, search_regs.start[i] + delta);
search_regs.end[i] = max (0, search_regs.end[i] + delta);
}
return Qnil;
}
/* Called from Flooking_at, Fstring_match, search_buffer, Fstore_match_data
if asynchronous code (filter or sentinel) is running. */
static void
@ -3388,6 +3405,7 @@ is to bind it with `let' around a small expression. */);
defsubr (&Smatch_end);
defsubr (&Smatch_data);
defsubr (&Sset_match_data);
defsubr (&Smatch_data__translate);
defsubr (&Sregexp_quote);
defsubr (&Snewline_cache_check);

6
test/lisp/subr-tests.el
View file

@ -545,7 +545,11 @@ See https://debbugs.gnu.org/cgi/bugreport.cgi?bug=19350."
(match-beginning 1) (match-end 1)))
"babbcaacabc")
"b<abbc,0,4,1,3>a<ac,0,2,1,1><abc,0,3,1,2>"))
)
;; anchors (bug#15107, bug#44861)
(should (equal (replace-regexp-in-string "a\\B" "b" "a aaaa")
"a bbba"))
(should (equal (replace-regexp-in-string "\\`\\|x" "z" "--xx--")
"z--zz--")))
(provide 'subr-tests)
;;; subr-tests.el ends here