From: Dave Thomas <Dave@...>
Date: 2002-11-21T14:42:35+09:00
Subject: Re: [FAQ] Interpreted vs compiled [FAQ] defining methods anywhere

Mark Wilson <mwilson13@cox.net> writes:

> Please explain how methods in an explicit class are different than
> methods in the Object class.

They aren't - it's just a question of when they are called:

   bert
   def bert
     ...
   end

Here, the call to bert is *executed* before the definition of bert: it
fails.

  class Dave
    def initialize
      bert
    end
    def bert
      ...
    end
  end

Here the call to 'bert' in initialize is parsed, but not executed. The
method 'bert' is then defined.

Later when you execute Dave.new, the call to bert succeeds, because
the method is defined at that point.

The fact that method definitions are active code means you can do
things such as

   if $DEBUG
      def fred
        puts "lots of logging"
        do stuff...
        puts "more logging"
      end
   else
      def fred
        do stuff...
      end
   end



Cheers


Dave