From: "Rubén Medellín" <CHubas7@...>
Date: 2008-03-06T10:35:04+09:00
Subject: Re: How to create a class in callers context??


> 1) What's the correct way to doing this?

Don't know the "correct" way, there is always more than one form to do
it. This is what I would do

class Class
  def generate(name)
    klass = Class.new
    klass.class_eval <<-EVAL
      def to_s
        "I'm a #{name}"
      end
    EVAL
    const_set(name, klass)
  end
end

class Universe
  generate :Planet
  puts Planet.new
  puts Universe::Planet.new
end

puts Planet.rescue "No Planet!"
puts Universe::Planet.new

_______
I'm a Planet
I'm a Planet
No Planet!
I'm a Planet
_______

alternatively you could do

klass = Class.new do
  def foo
    #...
  end
end

but then you can't pass a reference to the variable name. Don't know
if there's a way do do it, though.

If I wanted that to stick on a method, I would pass the binding as
well

class Factory
  def self.generate(name, _binding)
    eval <<-EVAL, _binding
      class #{name}
        def to_s
          "Hello from #{name}"
        end
      end
    EVAL
  end
end

> 2) I would have thought the non-qualified class references would have
> generated exceptions.

Very intriguing. I would have expected the same