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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?


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

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