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

From: Jacques-Olivier Goussard (jogoussard_at_[hidden])
Date: 2007-10-31 13:11:17

Great! I think I'm all set with this.
Thanks a lot - that's an amazing package.
          /jog

On 10/31/07, Eric Niebler <eric_at_[hidden]> wrote:
>
>
> Jacques-Olivier Goussard wrote:
> > *Eric Niebler*  wrote:
> >>'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.
> >
> > Ok, I've taken a look and that doesn't seem to be what I need afteral.
> > The regexp used must use the Perl semantic and are only known at
> > runtime, so I would go for what you call dynamic expressions, however
> > I'm not sure I see
> > how I can use your symbol table neat trick with those, unless they are
> > disconnected. I.e. I can easily translate
> > "in (CITY) on westbrook"
> > into
> > sregex leftre = 'in';
> > sregex rightre = 'on westbrook';
> > sregex re = leftre >> (city_map) >> rightre;
> >
> > but what to do with
> > "in (CITY|heaven) on westbrook" ?
>
>
> You're right, you can't /directly/ use symbol tables in dynamic regexes,
> but you can embed a static regex into a dynamic one. See the section on
> Dynamic Regex Grammars here: http://tinyurl.com/2nacj7.
>
> In particular, you can:
>
>    sregex_compiler comp;
>    // static regex, creates a symbol table from city_map:
>    comp["CITY"] = (a1 = city_map);
>    // dynamic regex calls static regex
>    sregex re = comp.compile("in ((?$CITY)|heaven) on westbrook");
>
> HTH,
>
> --
> Eric Niebler
> Boost Consulting
> www.boost-consulting.com
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