From: Greg Hurrell <greg.hurrell@...>
Date: 2007-02-26T19:10:05+09:00
Subject: Re: Writing a "String#jindex" method to do the same for "index" as "String#jlength" does for "length"

On 25 feb, 18:16, "Greg Hurrell" <greg.hurr...@gmail.com> wrote:
>
> So I guess this is a more general question. If something inside a
> method sets $~, how do you propagate this back to the caller? There
> was a thread called "How to preserve $~ when extending Regexp#match"
> last year that touched on a similar issue (http://groups.google.com/
> group/comp.lang.ruby/browse_thread/thread/73ccf213a9c0802d/
> a93554cd466acb44). This leads me to believe that the
> "special_local_set" function is being used under the hood by the
> "index" method and there will be no way for my "jindex" method to
> mimick its behaviour without also getting down into the C extension
> level, something I am not too keen to do as it is probably a bit over
> my head for now...

For the record, I decided to bite the bullet and try writing my first
C extension for Ruby. It works and uses rb_backref_get and
rb_backref_set to ensure that $~ gets correctly propagated back to the
caller. If anyone knows of a clean, pure-Ruby way to do this (without
a C extension) please let me know as it would be better from a
portability/deployment perspective.

Cheers,
Greg