Re: [boost] [Review] xpressive

From: Eric Niebler (eric_at_[hidden])
Date: 2005-09-21 18:27:09

Darren Cook wrote:
> Each new library adds to testing load,
> thins out the available maintainers, and increases the overwhelming
> feeling you get when you look at the boost library list.
> 
> So a new library should not be added just because it is clever, or
> slightly better at solving some problem than the existing ways. In my
> opinion, it has to be significantly better.
> 

I actually agree with this. But I think something is getting lost in 
this discussion: xpressive solves a different problem than Boost.Regex. 
Or rather, xpressive aims to solve a larger set of problems. It scales 
from regex all the way to context free grammars.

Did anybody read the message today entitled "[tools][bcp] using boost 
internally in other libraries" ?
http://article.gmane.org/gmane.comp.lib.boost.devel/131511

At the end, he says, "I have yet to complete support for replacing boost 
with nested namespaces since it is trickier to do the replacement of the 
ending braces of the namespace scope. I believe other tools than the
Regexp library may be more appropriate for this task."

The problem is that bcp uses Boost.Regex, except the poster wants to 
make a tweak that requires brace-matching. But Boost.Regex can't do 
that. Instead of a small tweak, the poster would have to throw bcp out 
and rewrite it using Spirit or some such. Had bcp been written using 
xpressive instead, no rewrite would be necessary. xpressive would scale 
to solve this problem.

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com