From: ptkwt@... (Phil Tomson)
Date: 2005-02-11T19:25:01+09:00
Subject: Re: [Newbie] Efficient method lookup from integer

In article <_3%Od.11807$8B3.7939@text.news.blueyonder.co.uk>,
James  <az@despammed.com> wrote:
>Hi,
>
>I've done much OO coding in perl 5 and I'm
>making the move over to ruby.
>
>Gosh, don't your programs get shorter!
>
>What would be a good ruby idiom to move efficiently from
>a positive integer in the range 0 to ~2000 to a specific
>method call?
>
>A case / when statement would do this simply, but in perl
>I sped this up by building a lookup table using
>an array containing references to the appropriate perl subs.
>

You could essentially do the same thing with some modifications.  First, 
you could build an array of symbols which are names of the method you want 
to call, something like:

  methods = []

  methods[0] = :foo
  methods[1] = :bar

.... etc.

Then you could put all of your methods into a class:

  class Methods
    def foo
      "foo" #foo behavior
    end
    def bar
      "bar" #bar behavior
    end
  end


Then you should be able to do:

  m = Methods.new
  m.method(methods[0]).call


Or, instead of storing symbols in your methods array , you could store 
Method objects and then just call them like so:

  methods[0].call

Phil