From: matt_neuburg@... (Matt Neuburg)
Date: 2009-06-11T01:15:07+09:00
Subject: Re: Match data variables

Lars Christensen <larschbelunktumdk@gmail.com> wrote:

> I understand that $~ and its friends ($&, $1, ...) are method local, but:
> 
> Can a custom method mimic the behaviour of String#match, String#=~ etc
> and set the match data for the caller?
> 
> def expect(pattern)
>   gets =~ pattern or fail
> end
> 
> expect /(\d+)/
> 
> p $1  #=> nil
> p $~  #=> nil  :-(
> 
> I would like $~ to contain the match data here.

Regexp.last_match is a MatchData object and you can do whatever you like
with it. For example:

def expect(str, pattern)
  str =~ pattern
  Regexp.last_match
end
res = expect("howdy", /h/)
p res.begin(0)

You could even set some *other* global to Regexp.last_match, if you're
in a "use globals" mood...

m.