[Chicken-users] Re: regex and named subpatterns

[Hans Nowak]

Robin Lee Powell wrote:

> I've just looked through "man perlre" fairly carefully and found
> nothing like this at all.  So I asked the Python regex
> documentation:
>
>     Python adds an extension syntax to Perl's extension syntax. If
>     the first character after the question mark is a "P", you know
>     that it's an extension that's specific to Python. Currently
>     there are two such extensions: (?P<name>...) defines a named
>     group, and (?P=name) is a backreference to a named group. If
>     future versions of Perl 5 add similar features using a different
>     syntax, the re module will be changed to support the new syntax,
>     while preserving the Python-specific syntax for compatibility's
>     sake.
>
> So, I'm afraid you're SOL.

It's no big deal, I don't really use it a lot personally, I just wondered if the 
feature was there.  The way I understand it, Chicken's regex module is based on 
PCRE, and the PCRE manual mentions the (?P<name>...) syntax:

       In PCRE, a subpattern can be named in one of three  ways:  (?<name>...)
       or  (?'name'...)  as in Perl, or (?P<name>...) as in Python. References
       to capturing parentheses from other parts of the pattern, such as back-
       references,  recursion,  and conditions, can be made by name as well as
       by number.

(At least according to http://www.pcre.org/pcre.txt.)

It's a bit odd though that Chicken (maybe unintentionally) supports the 
construct in regular expressions, but provides no ways to make use of it.

--Hans