Re: [Boost-users] Regexp without ^ and $

From: Stuart Dootson (stuart.dootson_at_[hidden])
Date: 2005-08-02 02:16:56

On 8/2/05, Merrill Cornish <merrill.cornish_at_[hidden]> wrote:
> I am using regex_match() from Boost 1.32.0.  I am well famililar with Perl's regular expression, but I got a surprise from Boost's regex_match().  My basic code is
> 
>         static const regex CHAR(" char ");
>         regex_match(newSpec, CHAR)
> 
> If newSpec is " char ", then it matches, of course.  However, if newSpec is " char * ", it doesn't match.  Hmmmm.
> 
> In my Perl experience, a regex of " char " says match those six characters if found ANYWHERE in newSpec.  This would mean that a Boost regex of " char " would match a newSpec of " char * ", but it doesn't seem to.
> 
> If I change the regex to ".* char .*", then it matches, implying that Boost's regex of " char " is being treated as if it were Perl's "^ char $".
> 
> I could add the ".*" before and after each of my (many) regular exressions.  However, I'm guessing there is a match_flag_type value which would do this for me.  Unfortunately, none of the match constant descriptions seem to be what I need.
> 
> How should I write a Boost regex so that it would find " char " anywhere in the input string regardless of any prefix or suffix?
> 
> Merrill

It's not the regex, it's the algorithm - use regex_search rather than
regex_match

HTH
Stuart Dootson