From: Andrew Stewart <boss@...>
Date: 2008-01-16T02:32:41+09:00
Subject: Overridding A Method Via A Mixin

Hi Everyone,

I believe one can add methods to a class by including a module but  
not override existing methods.  Indeed Dr Nic said as much here:

http://ruby.tie-rack.org/6/safely-overriding-method_missing-in-a- 
class-that-already-has-it/#comment-7

Here's some code that demonstrates this.

class Foo
   def answer
     42
   end
end

module Bar
   def answer
     "What was the question?"
   end

   def to_s
     "bar"
   end
end

Foo.send :include, Bar
f = Foo.new
f.answer  # => 42, not "What was the question?"
f.to_s    # => "bar", not "#<Foo:0x731248>"


Why aren't existing methods overridden?  And where could I have  
looked to find out the answer for myself (perhaps somewhere in Ruby's  
source?)?

Thanks and regards,
Andy

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