From: Ryan Leavengood <mrcode@...>
Date: 2005-06-27T05:31:25+09:00
Subject: Re: Defining a method vs aliasing it

David A. Black wrote:
> 
> I believe it's the other way around: aliasing a method name just adds
> another name for the same method.  If you then redefine the original
> method, the two names then point to different methods:
> 
>   class C
>     def x; end
>     alias :y :x               # y and x are the same method
>     def x; "new method"; end  # they are not the same
>   end
> 
> At least that's always been my understanding of it.

I thought you were correct, and irb agrees:

irb(main):001:0> class C
irb(main):002:1> def a;puts 'a';end
irb(main):003:1> alias :b :a
irb(main):004:1> end
=> nil
irb(main):005:0> c = C.new
=> #<C:0x2b60238>
irb(main):006:0> c.a
a
=> nil
irb(main):007:0> c.b
a
=> nil
irb(main):008:0> ma = c.method(:a)
=> #<Method: C#a>
irb(main):009:0> mb = c.method(:b)
=> #<Method: C#b>
irb(main):010:0> ma.call
a
=> nil
irb(main):011:0> mb.call
a
=> nil
irb(main):012:0> ma == mb
=> true
irb(main):013:0> ms = c.method(:to_s)
=> #<Method: C(Kernel)#to_s>
irb(main):014:0> ms.call
=> "#<C:0x2b60238>"
irb(main):015:0> ms == ma
=> false
irb(main):016:0> class C
irb(main):017:1> def b;puts 'b';end
irb(main):018:1> end
=> nil
irb(main):019:0> c.b
b
=> nil
irb(main):020:0> ma == mb
=> true
irb(main):021:0> mb = c.method(:b)
=> #<Method: C#b>
irb(main):022:0> ma == mb
=> false

Ryan