Re: [Boost-users] Xpressive, symantic actions and combination enumeration

Subject: Re: [Boost-users] Xpressive, symantic actions and combination enumeration
From: Eric Niebler (eric_at_[hidden])
Date: 2009-05-05 12:34:06

Lee Simpson wrote:
> Hi,
> 
> First let me say. Awesome library and thanks for releasing it to the world.

Thanks!

> I'm looking for a way to apply all the currently queued semantic actions 
> _without_ turning off backtracking.
> So, as the manual suggests, keep manages to apply the queued actions but 
> it also turns off backtracking.
>
<snip>
> 
> Any ideas?

You don't have to turn off backtracking for the whole regex. You can use 
keep() in a few strategic places within your regex as follows:

sregex rx = ... >> keep(nil[ /*semantic action*/ ]) >> ...;

"nil" always succeeds and consumes 0 characters. It's a way to cause the 
semantic action to execute immediately. Would something like that help you?

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