[Boost-users] [Xpressive] regex-like boost libraries vs re2c [was: Some timings [was: Baffled about results of search]]

From: Lynn Allan (l_d_allan_at_[hidden])
Date: 2006-04-13 13:29:08

Stuart Dootson wrote:
> Lynn - it might be interesting to use re2c (http://re2c.org/) to
> generate regex machines and see what their performance is like - 
> after
> all, they do clain 're2c generates warning free code that is equal 
> to
> hand-written code in terms of size, speed and quality.' (I'm 
> offering
> no opinion on the veracity of that statement....), so (allegedly)
> they'd give a reasonable hand-code analogue....

I took a look at it, and it looks like it could possibly be quite 
useful if executable size was a concern .... but it is pretty obscure 
(at least to me) .... the only example this dummy could make any sense 
out of at all was to recognize a number .... and that was 
missing/obscuring the important illustration of how to invoke and use 
the generated scanner code.

Were you able to get it to work to do anything even close to 
recognizing Days-of-the-Week (full and abbreviations)? Did you find 
actual compilable examples with "main" invoking the generated scanners 
with a test-string to crunch?

<alert comment="whining">

I really wish developers would provide COMPLETE "baby steps with 
training wheels" examples to flatten the learning curve. Eric N. did a 
great job of documenting and providing examples for xpressive .... 
that could be a model for other projects (not just boost).

I've subscribed to their sourceforge list and will swallow my pride 
and ask the newbie question:
"This dummy doesn't expect to be able to figure out your project in 30 
minutes ... how do you get it to something basic like recognize:"?

((Sunday|Sun)|(Monday|Mon)....(Saturday|Sat))

</alert>