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Subject: Re: [boost] [regex, xpressive] interesting(?) perf benchmark
From: Eric Niebler (eric_at_[hidden])
Date: 2010-06-07 12:10:51

On 6/7/2010 9:20 AM, Mathias Gaunard wrote:
> Eric Niebler wrote:
>> On 6/7/2010 5:50 AM, Mathias Gaunard wrote:
>>> Le 07/06/2010 04:58, Eric Niebler wrote:
>>>> I'm always suspect of benchmarks, but I figured I'd post this anyway.
>> <snip>
>>> Just an idea: for static xpressive, couldn't you detect at compile-time
>>> that the expression is truly regular, and use a DFA in that case?
>> Oh, sure! Why don't you submit a DFA and I'll use it in xpressive? ;-)
> How about a warning "you may not be using the optimal tool for the job"
> until then?

I'm having a hard time getting excited about that.

> Are the finite state machine libraries in Boost usable for this at all?

I don't know. At BoostCon, Christophe presented some interesting results
pitting MSM against xpressive for some simple regexing. An interesting
research project would be to investigate whether xpressive's hybrid
static/dynamic NFA design can be applied to DFAs as well, with similar
perf wins. This would be a non-trivial undertaking, like completely
reimplementing xpressive.

Eric Niebler
BoostPro Computing

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