compile-time regex redux

[Andrei Alexandrescu (See Website For Email)]

Bill Baxter wrote:
> Andrei Alexandrescu (See Website For Email) wrote:
>> Bill Baxter wrote:
>> [snip]
>>> I my opinion about regexps is that they're too dense and full of 
>>> abbreviations.  And the typical methods for creating them don't 
>>> encourage encapsulation and abstraction, which are the foundations of 
>>> software.  For instance, every time you look at the above you have to 
>>> re-interpret what [A-Z0-9._%-] really means.  When I'm writing 
>>> regular expressions I always have to have that chart next to me to 
>>> remember all those \s \b \w \S \W \ codes, and then again when trying 
>>> to figure out what the code does later.  There has to be a better 
>>> way.  Apparently the Perl guys thing so too, because they're redoing 
>>> regular expressions completely for Perl 6.
>>
>> (Well not completely.) That's why we should keep a close eye on those. 
>> The Perl community is much more experienced with regex usage than me 
>> and possibly yourself. I just want us to not delude ourselves with the 
>> idea that we could just sit down and write a better regex syntax just 
>> because we don't remember what \s and \b mean. (I happen to remember. 
>> :o))
> 
> Yes and I don't want us to go and make Perl5-ish regular expressions 
> part of the core D language spec without understanding how and why that 
> very expert Perl community is changing their regular expressions in the 
> next round.  I haven't followed developments with Perl 6 closely, 
> though.  Just glanced at the link someone posted the other day.

I did. Perl 6 is going to be great. The regexes had a few warts that 
were overdue for a fix. The spirit remains the same, and the new 
full-fledged grammars will take care of the larger parsing tasks.

> I also don't want us to go make regexp part of the language spec without 
> thoroughly ruling out the potentially much cooler ability to write that 
> regexp parser using more fundamental but yet-to-be-invented building 
> blocks.

I think that's a great spirit.


Andrei