Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: Matthew Chambers (matthew.chambers_at_[hidden])
Date: 2009-07-01 17:23:35

Why is Xpressive more readable than using lexical_cast or your 
numeric_cast? I've implemented specializations of lexical_cast for 
string->numeric conversions using strto[ld]. It is a vast speed 
improvement of course, and since those specializations are hidden away 
in a header, readability is the same as with normal lexical_casts. Maybe 
I'm misunderstanding your use case? Do you not know ahead of time what 
the type of the number will be?

-Matt

Dave Jenkins wrote:
>> Whoa!  The performance just shot up to a mere 6X the custom code 
>> (from 175X).  That might well be fast enough to keep the Xpressive 
>> version because of its readability!
>
> Can you create thread-local match_results objects and reuse them?  If 
> so, I think you'll see parsing dwindle to almost nothing and your 
> semantic actions will account for the bulk of the time spent.
>
> Regards,
> Dave Jenkins
>