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Subject: Re: [boost] [xpressive] Performance Tuning?
From: Dave Jenkins (david_at_[hidden])
Date: 2009-07-09 12:08:15

From: "Stewart, Robert" <Robert.Stewart_at_[hidden]>
> Your hopes were justified: I just noticed that while my TLS accessor
> returns a reference to the smatch, I saved it to a copy rather than a
> reference where I was using it. Correcting that mistake shows the
> Xpressive code taking around 1.5X the time used by the custom code.
> I've seen added more test cases and updated the custom code and must now
> correct some things in the Xpressive code to handle all of the same cases
> before I can do any more measurements.

Thanks for doing this work Rob. It's been a really fruitful exercise.

I had one other question on performance improvement, mostly for Eric. Could
you eliminate/minimize the need for match_results when semantic actions are
capturing the results? In Rob's code, he's not even looking at the
match_results because his semantic actions handle the data. Can you
optionally turn off the match_results capture in that case to save space and

Dave Jenkins

P.S. If I'm slow to respond, it's because I'm on vacation and internet
access is spotty.

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