[Emacs-bug-tracker] bug#6388: closed (Should not match data be set on misses?)

[GNU bug Tracking System]

Your message dated Wed, 09 Jun 2010 22:03:08 -0400
with message-id <address@hidden>
and subject line Re: bug#6388: Should not match data be set on misses?
has caused the GNU bug report #6388,
regarding Should not match data be set on misses?
to be marked as done.

(If you believe you have received this mail in error, please contact
address@hidden)


-- 
6388: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=6388
GNU Bug Tracking System
Contact address@hidden with problems
> --- Begin Message ---
>
>
>
> Subject: 
>
> Should not match data be set on misses?
>
>
>
>
> Date: 
>
> Thu, 10 Jun 2010 02:42:59 +0200
>
>
>
>
> (let ((ret (re-search-forward "some weird thing" (point-at-eol) t)))
>   (message "ret=%s, mb0=%s, 1" ret (match-beginning 0) (match-beginning 1)))
>
> gives me messages like
>
>    ret=nil, mb0=517, 1
>
> I expected
>
>    ret=nil, mb0=nil, nil
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#6388: Should not match data be set on misses?
>
>
>
>
> Date: 
>
> Wed, 09 Jun 2010 22:03:08 -0400
>
>
>
>
> > From: Lennart Borgman <address@hidden>
> > Date: Thu, 10 Jun 2010 02:42:59 +0200
> > Cc: 
> > 
> > (let ((ret (re-search-forward "some weird thing" (point-at-eol) t)))
> >   (message "ret=%s, mb0=%s, 1" ret (match-beginning 0) (match-beginning 1)))
> > 
> > gives me messages like
> > 
> >    ret=nil, mb0=517, 1
> > 
> > I expected
> > 
> >    ret=nil, mb0=nil, nil
>
> I'm closing this bug report because the ELisp manual explicitly
> documents the current behavior:
>
>       Every successful search sets the match data.  Therefore, you should
>    query the match data immediately after searching, before calling any
>    other function that might perform another search.  Alternatively, you
>    may save and restore the match data (*note Saving Match Data::) around
>    the call to functions that could perform another search.
>
>       A search which fails may or may not alter the match data.  In the
>    past, a failing search did not do this, but we may change it in the
>    future.  So don't try to rely on the value of the match data after a
>    failing search.
>
> Patches welcome to "change this in the future" (unless Stefan or
> Yidong object to such a change).
>
>
> --- End Message ---