GNU bug report logs - #18762
[PATCH] dfa: don't consider RE_DOT_NEWLINE and RE_DOT_NOT_NULL in matching with a bracket expression

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Message #22 received at 18762-done <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Cc: 18762-done <at> debbugs.gnu.org
Subject: Re: bug#18762: [PATCH] dfa: don't consider RE_DOT_NEWLINE and
 RE_DOT_NOT_NULL in matching with a bracket expression
Date: Sun, 19 Oct 2014 18:24:56 -0700

[Message part 1 (text/plain, inline)]

On Sat, Oct 18, 2014 at 7:07 PM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
> Jim Meyering <jim <at> meyering.net> wrote:
>> dfa.c's match_mb_charset function *is* used, e.g., in a
>> command like this one:
>>
>>   printf '\0' |src/grep -aE '^\s?$'
>
> Wow, just it isn't good.  I think that behavior of `fails' should be
> same as of `trans' except `fails' checks accepted conditions, including
> following part.  match_mb_charset() should be avoided as far as possible,
> as it doesn't support collating symbols and equivalence classes.
>
>>               /* Falling back to the glibc matcher in this case gives
>>                  better performance (up to 25% better on [a-z], for
>>                  example) and enables support for collating symbols and
>>                  equivalence classes.  */
>>               if (d->states[s].has_mbcset && backref)
>>                 {
>>                   *backref = 1;
>>                   goto done;
>>                 }

Nice change.  I've adjusted the commit log and added the test
above, since no other code even excercised the
now-inaccessible function. I will push it tomorrow.

[0001-dfa-process-all-MBCSET-constructs-via-glibc-s-matche.patch (application/octet-stream, attachment)]

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