From: kushcs@... (Christopher S. Kush)
Date: 2001-12-06T13:52:06+09:00
Subject: [ruby-talk:27609] Emulating multimethods

Okay,

I'm writing my first Ruby code *ever* today, so go easy on me.

I want to write a class that emulates a piece of hardware.  The
hardware spec I'm working from says that the Hardware reacts to
different Inputs differently, depending on its State.

Now, in CLOS, I could write multimethods and the runtime would
just handle everything.  But Ruby doesn't have that (yet (hint,
hint)), so I came up with the following:


  class Hardware

    def crunch_input_X_in_state_Y( x, y )
      @input = x
      @state = y
      self.send( "crunch_input_" + x.name + "_in_state_" + y.name )
    end

    def crunch_input_Foo_in_state_Sleeping
      # mess with stuff
    end

    def crunch_input_Bar_in_state_Happy
      # mess with stuff
    end

  end