From: "David A. Black" <dblack@...>
Date: 2003-11-22T21:25:34+09:00
Subject: Re: behaviour change of String#gsub(pattern) {|m| ... } for ruby 1.9/ruby2?

Hi --

On Fri, 21 Nov 2003, Florian Gross wrote:

> Yukihiro Matsumoto wrote:
> 
> > Hi,
> 
> Moin!
> 
> > |String#gsub(pattern) {|m| ... }
> > |
> > |It really would be nice to get match data in 'm', but this would surely
> > |break _a lot_ of scripts. How about String#regsub, #regsub!, #resub, 
> > |#resub! ? What do others think?
> > 
> > Sounds nice.  The only reason for the current behavior is that sub
> > predates MatchData.  But we have to define migration path.
> 
> I like this, because matz told me I shouldn't be using $1 in the 
> gsub-block and there's no way to not do so right now. :)

I've also just noticed this:

  irb(main):001:0> "abc".gsub(/((x?)abc)/) {|n,m| p n, m}
  "abc"
  nil

as opposed to:

  irb(main):002:0> /((x?)abc)/.match("abc").captures
  => ["abc", ""]

which makes it hard to do, say, downcasing of a capture in #gsub,
without checking it for nil-ness or, as you say, using $1 and friends.


David

-- 
David A. Black
dblack@wobblini.net