From: Claus Spitzer <DocBoobenstein@...>
Date: 2004-08-15T04:31:11+09:00
Subject: creating classes on the fly

Greetings again! I'm trying to create a user-defined class on the fly.
The idea would be for the user to provide a class name, maybe a
superclass name, and some method definition as a string, e.g.

  str1 = "MyClass"
  str2 = "Class"
  str3 = "def bar \n p \"bar!\" \n end"

and then my program would perhaps do something like 

  eval "class #{str1} < #{str2}\n #{str3} \n end"

So far so good. Security is not a concern, this is just for a proof of
concept. But I would like to be able to then extend MyClass
separately, e.g.

  module Mod
    def bar
       p "foo!"
    end
  end

  class ???
     include Mod
  end

I'm stuck on the ??? part. I tried 

  class eval( str1 )

I tried

  class str.intern # (I think I know by now why this one was a stupid idea)

I tried 

  $myclassref = eval str1
  class $myclassref

All to no avail. So I'm wondering whether I'm trying to do this the
wrong way. What would be the Ruby way of solving this problem?