From: Tom Werner <pubsub@...>
Date: 2006-12-14T04:33:17+09:00
Subject: Re: How to overload the operator !=?

ankyhe@gmail.com wrote:
> I overload ==, >, <, >=, <=successfully, however I can't overload != .
> How to overload operator !=?
>
>
>
>   

The != token is not really a method at all and thus cannot be redefined. 
It is, rather, syntactic sugar that calls == and negates the result. You 
can see for yourself that this is true:

class Foo
  def ==(other)
    puts '== called'
    true
  end
end

f1 = Foo.new
f2 = Foo.new

f1 == f2
f1 != f2

Which outputs

== called
== called

And upon reflection, this makes sense, as in any sane world !(f1 == f2) 
will equal (f1 != f2), and so redefining != would be redundant.

Tom