From: Ed Sinjiashvili <edsin@...>
Date: 2002-04-01T20:59:59+09:00
Subject: Re: re-extending object

ts <decoux@moulon.inra.fr> writes:

>  Why you don't use a State pattern ?
Thanx for the snippet, I used similar scheme, but without automated
#method_missing dispath. Still my question was - Could I use *Module*
mixins to implement that pattern? 

>  In your case a *STUPID* implementation
Is it stupid to expect that mixin will override methods that already
present in the object? Or is it stupid to use #extend - 'cause it can
be used more than once per mixin?
whailer% cat stupid.rb
module A
  def a() puts "A#a" end

  def b() puts "A#b" end
end

module B
  def b() puts "B#b" end

  def c() puts "B#c" end
end

module C
  def c() puts "C#c" end

  def a() puts "C#a" end
end

a = Object.new
a.extend A
a.a; a.b; puts 

a.extend B
a.a; a.b; a.c; puts

a.extend C
a.a; a.b; a.c; puts

a.extend A # stupid???
a.a; a.b; a.c
whailer%

whailer% ruby stupid.rb
A#a
A#b

A#a
B#b
B#c

C#a
B#b
C#c

C#a
B#b
C#c
whailer%

--Ed