Re: [Boost-users] REGEXP - Serializing regexp ?

From: Jacques-Olivier Goussard (jogoussard_at_[hidden])
Date: 2007-10-30 16:01:21

Thanks a lot, I'll take a look - it seems very promising.
Does it support wchar_t ? Another requirement of mine I'm afraid :)
        /jog

On 10/30/07, Eric Niebler <eric_at_[hidden]> wrote:
>
>
> Jacques-Olivier Goussard wrote:
> > Thanks for taking the time to answer John.
> >
> >  > How desperate are you? Are there really that many regexes that
> > loading them
> >  > from their string representation is a problem?
> >
> > Well, not *that* desperate - I'm looking at the existing options for
> now.
> > The number of regexp is roughly 4000 currently but unconstrained a
> priori
> > and a lot of them are quite huge. Futhermore, the match is done for all
> > those regexps on a list of string that can contain around 1 million
> strings
> > (so recompilation each time of the regexp is likely to be a problem).
> >
> > The problem is the following: I'm supposed to implement a  match
> > on general tokens, i.e. being able to code regexps that would
> > contain tokens like:
> > (CITY)
> > where CITY is defined elsewhere as a list of possible cities.
> > The only way I see to do this with boost-regexp is to translate those
> > pseudo-regexp
> > into ones containing
> > (boston|chicago|.....)
> > I.e. replace all references to generic tokens to their expanded value -
> > I'm afraid
> > that will use too much mem (if all loaded) or too much time (if
> > recompiled each time) -
> > unless there is a way to refer to another regexp in a regexp ?
>
>
> I'll second the suggestion to look into xpressive. With xpressive, you
> can refer to one regex from another. And with the latest version (in the
> Boost Sandbox) you can put your list of cities into a symbol table and
> get very fast look-up -- much better than just a bunch of alternates.
>
> You can read about xpressive's symbol tables here:
>
> http://boost-sandbox.sourceforge.net/libs/xpressive/doc/html/boost_xpressive/user_s_guide/symbol_tables_and_attributes.html
>
> HTH,
>
> --
> Eric Niebler
> Boost Consulting
> www.boost-consulting.com
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