From: Austin Ziegler <halostatue@...>
Date: 2005-09-28T06:58:54+09:00
Subject: Re: Dynamically generating classes?

On 9/27/05, Jonas Galvez <jonasgalvez@gmail.com> wrote:
> In Python I can do this:
> >>> def create_class(name):
> ...     import new
> ...     c = new.classobj(name, tuple([object]), {})
> ...     def __init__(self, value):
> ...         self.value = value
> ...     setattr(c, "__init__", new.instancemethod(__init__, None, c))
> ...     return c
> ...
> >>> MyClass = create_class("MyClass")
> >>>
> >>> obj = MyClass(value=10)
> >>> print obj.value
> 10
>
> Is there anything similar in Ruby? Or do I need to use eval()?

  def create_class(parent = nil)
    if parent
      klass = Class.new(parent)
    else
      klass = Class.new
    end
    klass.class_eval do
      def initialize(value)
        @value = value
      end

      attr_reader :value
    end
    klass
  end

  MyClass = create_class
  obj = MyClass.new(10)
  puts obj.value

The only difference is that the class's name is based on the first
constant it's given to. That's a bit of RubyMagic.

-austin
--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca