Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: John Bytheway (jbytheway+boost_at_[hidden])
Date: 2009-07-19 04:29:38

OvermindDL1 wrote:
> I just changed the file to use spirit for parsing where I had used
> lexical_cast got very different timings for xpressive now, so now,
> with xpressive using a bit of spirit I get:
> Loop count:  10000000
> Parsing:  42.5
> xpressive:  15.4841
> spirit-quick(static):  3.01117
> spirit-quick_new(threadsafe):  3.10548
> spirit-grammar(threadsafe/reusable):  3.81694
> 
> Vast increase, 3x faster xpressive is now.
> Also, how do you fix that rather bloody massive warning about
> double->int64 truncation?
> I also changed all int64_t to boost::long_long_type since they are the
> same thing anyway (on 32-bit at least?), as well as it being
> multi-platform unlike int64_t.
> My changed file is attached.  Do not know if this is considered
> cheating now that xpressive is using some spirit now.  ;-)

That one doesn't compile for me.  On line 402:

boost::spirit::qi::parse(va.begin(), va.end(),
boost::spirit::double_[boost::phoenix::ref(value)]);

I get

no instance of overloaded function "boost::spirit::qi::parse" matches
the argument list

(and the same on all the similar lines)

and indeed I see can't see an appropriate overload in the spirit headers
(in boost trunk), but it's hard to be sure since there are so many
functions called parse!

John Bytheway