From: dblack@...
Date: 2006-07-16T08:00:27+09:00
Subject: Re: Help with a regexp

Hi --

On Sun, 16 Jul 2006, Daniel Martin wrote:

> dblack@wobblini.net writes:
>
>> On Sat, 15 Jul 2006, Daniel Martin wrote:
>>> Perl allows bunches of special constructs in regular expressions that
>>> sane languages, which like to keep the matching of regular expressions
>>> away from being able to jump back into the host language.  (Note that
>>> perl combines this feature with extra language-level security support,
>>> since most programmers would assume that a user-supplied regexp
>>> couldn't execute arbitrary code)
>>
>> Ruby does let you jump back, though, with #{...}.  But it looks like
>> Perl does an extra level of compilation.  (Unless I've got that
>> backwards.)
>
> Ruby lets you do string interpolation with an easy syntax, and lets
> you use that syntax even when writing a string that is being compiled
> into a regular expression because it's surrounded by //.  Perl has
> that, too.  This however is something different - the execution of
> code in the host language at regular expression long after the
> expression has been compiled, in the middle of doing a match.

Right, I see what you mean.  I think with "extra level of compilation"
that's what I was groping toward -- really a post-compilation
evaluation in a later context.

Thanks --


David

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