Re: Bigloo Regexp: m/ /ms (now: Regular Parsing)

Le 2015-04-22 08:44, [email protected] a écrit :

>> Well, I wrote a little grammar (see attachment), but I don't see any 
>> way to pass the pattern as an argument to the grammar, is it possible?

> You cannot as REGULAR-GRAMMARs are compiled. If you need to compute new 
> grammars at runtime, you will have to use eval :-(. For instance, you 
> can use something such as:

   (define (mk-regular-grammar pattern)
      (eval `(regular-grammar () (,pattern "blabla"))))

> Although not recommended in general, this solution will deliver decent 
> performance in your case.

As the system we try to emulate is a Python library, the performance 
should be comparable.

> The other solution would be to use pregexp (your first intuition) but 
> as pregexp requires a string, you will have to read the whole file in 
> memory first, which means that this solution will only work for toy 
> examples.

> As a side note, if your pattern is basic regular expression only made 
> of sequences of characters, then you might prefer using KPM and mmap.

KMP, I suppose? We need Regexps more complex than just strings. But I am 
curious about the way Perl manages multi-lines queries, we would do the 
same.

Cheers.

-- 
Laurent Bloch - http://www.laurentbloch.org/ - [email protected]