Bug Report -- replace-regexp-in-string from subr.el

Bug Report -- replace-regexp-in-string from subr.el

[Sam Fiechter]

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Hi,

I noticed that the lisp function replace-regexp-in-string from emacs
24.4.50.1 does not pass the sub-expression match when the rep is a function
call rather than a string.
For Example:
(progn
  (defun samscat (s)
      (concat "[" s "]"))
 (replace-regexp-in-string "\\(foo\\).*\\'" 'samscat " foo foo" nil nil 1))

returns:
" [foo foo] foo"
 not:
" [foo] foo"

looking at the code, I notice that the sub-expression is hard-coded on line
3642 of subr.el.gz:
     (funcall rep (match-string 0 str)))
rather than:
     (funcall rep (match-string (or subexp 0) str)))

I hope this is helpful!

Here's my about emacs screen:
This is GNU Emacs, one component of the GNU/Linux operating system.

GNU Emacs 24.4.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.10)
 of 2014-03-30 on lenovo-laptop
Copyright (C) 2014 Free Software Foundation, Inc.

If you would like any other info please let me know.

Best,

Sam

-- 
Sam Fiechter
(302) 689-3798

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Re: Bug Report -- replace-regexp-in-string from subr.el

[Andreas Schwab]

Sam Fiechter <sam.fiechter@gmail.com> writes:

> I noticed that the lisp function replace-regexp-in-string from emacs
> 24.4.50.1 does not pass the sub-expression match when the rep is a function
> call rather than a string.

Which matches the documentation:

    REP is either a string used as the NEWTEXT arg of `replace-match' or a
    function.  If it is a function, it is called with the actual text of each
    match, and its value is used as the replacement text.  When REP is called,
    the match data are the result of matching REGEXP against a substring
    of STRING.

The "actual text of each match" is (match-string 0), not (match-string
subexp).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Bug Report -- replace-regexp-in-string from subr.el

[Davis Herring]

>     REP is either a string used as the NEWTEXT arg of `replace-match' or a
>     function.  If it is a function, it is called with the actual text of each
>     match, and its value is used as the replacement text.  When REP is called,
>     the match data are the result of matching REGEXP against a substring
>     of STRING.
> 
> The "actual text of each match" is (match-string 0), not (match-string
> subexp).

If it's not obvious, you can write (match-string 1 s) in your
replacement function to get the desired behavior.

Davis

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