From: Kedar Mhaswade <kedar.mhaswade@...>
Date: 2011-01-10T08:36:13+09:00
Subject: Confusion regarding boolean operators.

Apologies if this has been asked before (I tried to search).

David and Matz write in their excellent book (Thanks, Gary Wright, for
the reference) in section 4.6.8 that:
------------------------------------------------------
Ruby's Boolean operators (which I assume mean &&, ||, !, not, and, or)
are not based on methods: classes for example, can not define their own
&& method.
------------------------------------------------------

I have two questions in this regard:
1. Is is applicable to only &&, || etc. and I can still define the !
method so that !var calls my method? (I find that to be the case, See
[1])

2. How is !var converted to a method call var.! ? (which is what I find)

This is with 1.9.2.

Thank you.

-Kedar

[1]
#!/usr/bin/env ruby

class Human
  attr_accessor :name
  def initialize(name)
    @name = name
  end
  def to_s
    "Human: #{@name}, I am not God"
  end
end

class God
  def !
    puts "method ! called"
    Human.new("me")
  end

end
god1 = God.new
puts !god1   # prints Human:me, I am not God

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