Re: [Boost-users] RegEx Exception

From: John Maddock (john_at_[hidden])
Date: 2006-03-28 04:19:32

>> I'm using the latest version of the boost regex libraries and am
>> receiving an exception when using the regex_replace function with
>> the following regular expression:
>>
>> (?i)(?<!')((<\s*OBJECT\s*[^>]+classid="clsid:[^>]+?(?<!\s*/\s*)>[^*]+?<\s*/\
>> s*OBJECT\s*>)|(<\s*OBJECT\s*[^>]+classid=\s*\"clsid:[^/>]+/))
>>
>> ..which works in other industry standard regex library routines.
>>
>> I seem to be failing on line 767 of basic_regex_creator.hpp.

That happens when you have a lookbehind expression that's not supported: as 
Eric has already pointed out Boost.Regex doesn't support variable width 
lookbehind, neither do PCRE or or Perl as far as I know.  It's technically 
possible to do, although doing so efficiently is quite hard, and for 
questionable gain at present.

HTH, John.