[boost] [regex] regex_match algorithm strategy?

From: Lorenzo Bettini (bettini_at_[hidden])
Date: 2007-08-01 10:36:41

Hi

I have to split a regular expression of the shape (simplified for this 
example)

(?:\<(or)\>)|((?:[[:word:]]+)[[:blank:]]*(?=\())

the idea is to match (actually with regex_search algorithm) or as a 
keyword and to match function names in function invocations (or 
declarations); i.e.,

or (

should be matched as the keyword "or" and then a parenthesis, but

foo (

"foo" should be matched as a function name

the above expression works correctly (and I've always used that one).
Now, I had to split that expression into two regular expressions

(?:\<(or)\>)

((?:[[:word:]]+)[[:blank:]]*(?=\())

and try to match the above situations the same way.
Thus, I'm trying to match each one and then take the one that matched 
first with the biggest length (and smallest prefix but this is not 
important now);
of course I don't get the desired behavior, since in

or (

"or" is matched as a function name.

Thus I was wondering: which is the actual algorithm used by 
regex_search?  Does it take into consideration other things beside the 
biggest length?

thanks in advance
        Lorenzo

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Lorenzo Bettini, PhD in Computer Science, DSI, Univ. di Firenze
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