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Re: benefits of SRE syntax



On 10/20/2013 07:21 AM, Alex Shinn wrote:
On Thu, Oct 17, 2013 at 4:14 AM, Per Bothner <per@xxxxxxxxxxx
    I think structured regular expressions make sense when integrated
    with a general pattern-matching framework (by which I mean something
    like http://docs.racket-lang.org/__reference/match.html
    <http://docs.racket-lang.org/reference/match.html>). Also,
    sub-matches should produce variable bindings.

I think it would be strange to provide regexp
matching as part of a general matching framework
without providing access to the underlying regexp
library.

You're assuming there is an underlying regexp library
for handling strings regexps.  But that assumes a
separate syntax and operators for strings regexp matching.
However, a more integrated approach is possible and IMO
preferable, where regexps are matched against general
sequences, not just strings.

I suggest taking a look at CDuce (or its precursor XDuce)
http://www.cduce.org/papers/cduce-design.ps.gz
http://www.cduce.org/manual_types_patterns.html

I think this is a much more elegant approach, and much more
in the "spirit of Scheme" (if you take away the static typing
aspect - which of course I like).

If "structured regular expressions" are to be part of the
language, we should think about how they apply to sequences
(lists and vectors) in general, not just strings.
--
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/