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[Bug 1851] [F&O] back references to a group that was captured 0 times?

From: <bugzilla@wiggum.w3.org>
Date: Wed, 05 Oct 2005 01:54:38 +0000
To: public-qt-comments@w3.org
Cc:
Message-Id: <E1EMyUQ-0006KV-7y@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=1851


weiran.zhang@oracle.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|CLOSED                      |REOPENED
         Resolution|FIXED                       |




------- Additional Comments From weiran.zhang@oracle.com  2005-10-05 01:54 -------
I think this may not be the best behavior. In effect, this is imposing a default
value of zero-length string on back-references, which makes it impossible to
differentiate among sub-expressions that actually matched the zero-length
string, sub-expressions that didn't participate in the match, and invalid
sub-expression references. A pattern like '(a)*\1' will match anything under
this interpretation. Conceptually it is also confusing to the user since
non-empty subexpressions should not match an empty string. None of the popular
implementations I know of (Perl, Java, etc.) behaves this way.
Received on Wednesday, 5 October 2005 01:54:44 UTC

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