ID: 49550
User updated by: spoon dot reloaded at gmail dot com
Reported By: spoon dot reloaded at gmail dot com
Status: Bogus
Bug Type: PCRE related
Operating System: Linux
PHP Version: 5.3.0
New Comment:
oops my previous workaround still doens't work
echo preg_match('/^$|^(.(?:|(?1)))$/', 'abc'), "\n";
Previous Comments:
------------------------------------------------------------------------
[2009-09-14 11:05:33] spoon dot reloaded at gmail dot com
oops in that last one I meant
echo preg_match('/^$|^(.(?:|(?1)))$/', 'ab'), "\n";
------------------------------------------------------------------------
[2009-09-14 10:58:29] spoon dot reloaded at gmail dot com
I found a solution:
echo preg_match('/^|(.(?:|(?1)))$/', 'ab'), "\n";
but I still don't understand why the other one doesn't work
------------------------------------------------------------------------
[2009-09-14 10:49:09] spoon dot reloaded at gmail dot com
But that still wouldn't explain why stuff like balanced parentheses
matching /^(\(((?>[^()]+)|(?1))*\))$/ works. I am still waiting for an
explanation on my example.
------------------------------------------------------------------------
[2009-09-14 10:24:41] spoon dot reloaded at gmail dot com
Nevermind, so I think the reason is that PCRE differs from Perl in that
a recursive "sub-"pattern (i.e. ?1, ?2, etc. but not ?0) only matches
exactly what was matched before by that subgroup, even if there are
other unused possibilities by that group. Is that correct?
------------------------------------------------------------------------
[2009-09-14 10:06:30] spoon dot reloaded at gmail dot com
> Remove the $ and it works.
Yeah but that changes the meaning. I want to enforce that it matches
the entire string, and it doesn't do that.
To give another example without a $, consider:
echo preg_match('/^(|.(?1))x/', 'abx'), "\n";
Again, it works in Perl, but not in PHP.
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/49550
--
Edit this bug report at http://bugs.php.net/?id=49550&edit=1
