From: Minero Aoki <aamine@...>
Date: 2000-11-11T14:59:57+09:00
Subject: [ruby-talk:6267] Re: aliasing class methods

Hi David,

  In mail "[ruby-talk:6264] aliasing class methods"
    David Alan Black <dblack@candle.superlink.net> wrote:

> Hello --
> 
> Is there more compact way to alias class methods than this
> (i.e., without the necessity of "class << self ... end")?

This is a little "illegal" way, but usable:

class T
  def T.a
    puts 'a called'
  end
  instance_eval "alias b a"
end
T.a   #-> a called
T.b   #-> a called


And we can make this code more compact by the following way:

class Module
  def alias_class_method( new, old )
    instance_eval "alias #{new.id2name} #{old.id2name}"
    # or "instance_eval { alias_method new, old }"
  end
end

class T
  alias_class_method :c, :a
end
T.c   #-> a called


> In a related vein: what functionality does alias_method add to alias?
> I've been playing with both, and in cases where either works, both
> seem to work (even if with slightly different syntax).

In a word, "alias" is required to aliasing global variables.
"alias_method" is required to using in method.


Minero Aoki