Re: [Boost-users] [regex] Context-sensitive replacement oftextusingregex_replace

Subject: Re: [Boost-users] [regex] Context-sensitive replacement oftextusingregex_replace
From: John Maddock (john_at_[hidden])
Date: 2009-02-25 13:59:24

> I don't think such a callback would be useful to the OP. If the callback
> merely accepts the matched string, it would need to reparse the string
> to find the sub-matches. In addition, accepting and returning strings
> imposes unnecessary dynamic allocations.
>
> Xpressive's regex_replace() algorithm can accept a formatter function or
> function object with one of three different signatures. It can either:
>
> a) Accept the match_results object, and return a std::string, or
> b) Accept the match_results object and an output iterator, and return
>    the output iterator, or
> b) Accept the match_results object, an output iterator and the match
>    flags, and return the output iterator.
>
> You can read about it here: http://tinyurl.com/bd6c3f. I like this
> interface because it gives the formatter object lots of context and
> makes formatting potentially very efficient.
>
> It would be great if Boost.Regex and Boost.Xpressive settled on a common
> callback interface for regex_replace().

I think the interface you have there is very good - I'd always assumed that 
the callback would accept a match_results not a string - as you say the 
performance would be just so much better...

John.