Re: [Boost-users] [xpressive] static expression adding

Subject: Re: [Boost-users] [xpressive] static expression adding
From: Eric Niebler (eric_at_[hidden])
Date: 2009-02-12 10:48:35

Jan Boehme wrote:
> Hi,
> 
> is it possible to add  an expression to an already existing expression object?
> 
> Something like:
> 
> sregex re = '$' >> +_d >> '.' >> _d >> _d;
> 
> replace by:
> 
> sregex re = '$';
> re += +_d;
> re +=  '.' >> _d >> _d;
> 
> My attempts did result in compile time troubles.

You can nest regular expressions to get the same behavior.

sregex re0 = as_xpr('$');
sregex re1 = re0 >> +_d;
sregex re2 = re1 >> '.' >> _d >> _d;

You lose most of the benefits of static regular expressions when you do 
this, though.

HTH,

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com