From: David Alan Black <dblack@...>
Date: 2004-05-31T21:33:44+09:00
Subject: Re: gsub!, replace with \'

Hi --

Simon Strandgaard <neoneye@adslhome.dk> writes:

> I think I read somewhere that perl6 uses $ in the regexp replacement string,
> in order to avoid our escaping hell.  I think this is a good initiative.
> So escape can be used freely:
>   "hello".gsub!(/h/, %q|\'|)       #->  \'ello
>   "hello".gsub!(/(.)$1/, '$&$1')   #->  helllo
> 
> Maybe we should do an RCR..  use dollar in regexp?

Hmmm... I thought Ruby was moving more in the direction of getting rid
of Perl-like global variables :-) But anyway, I think the thing you're
describing might lead to some awkward things.  I think it's more logical
to treat $1 as just a regular variable for purposes of compiling the
regular expression:

  /(def)/.match("abcdef")
  puts $1                                 # def
  /ABC#{$1.upcase}/.match("whatever")

If your change were made, $1 would be nil in the last line because
there are no captures.  

And here, you'd get a kind of postponed compilation of re:

  /(abc)/.match("abc")
  re = /(blah)#{$1}def/

Sorry for the dumb examples... but I think the problems would be real.


David

-- 
David A. Black
dblack@wobblini.net