From: Robert Klemme <shortcutter@...>
Date: 2011-03-26T00:33:28+09:00
Subject: Re: Dynamic classes

On Fri, Mar 25, 2011 at 3:25 PM, PsiPro <arjesins@gmail.com> wrote:
> So I am working on some metaprograming and have some questions about
> how to get what I need out of dynamic classes.
>
> Right now I know I can define dynamic classes like so:
> a) TestClass = Class.new
> b) var_class = Class.new
>
> These work as expected but I need the functionality provided by case
> A. Specifically I need to have the instances respond to .class
> appropriately. .class for case B returns Class, while case A responds
> TestClass

Case b cannot return Class.  You would rather see something like this:

16:10:04 ~$ ruby19 -e 'TestClass = Class.new; p TestClass.new.class;
var_class = Class.new; p var_class.new.class'
TestClass
#<Class:0x1003b03c>

> The reason I need to do this is that I want to dynamically generate
> classes, including their names. How can I accomplish this?
>
> My desired results:
>
> variable = Class.new
> variable.class.name == 'variable'

Magic works only with constants.  The first constant that a Class or
Module instance is assigned determines its name.

> OR, I need to be able to assign a dynamic constant name (I know I
> know).

16:30:47 ~$ ruby19 -e 'x=Class.new;Object.const_set("Foo",x);p x, x.new.class'
Foo
Foo

Why do you need this?  Maybe you can do

classes = {}

classes["Foo"] = Class.new do
  def nifty_method
    42
  end
end

Now you can do

obj = classes["Foo"].new

You could even override Class#name or #to_s per instance to return the
proper value, if you must have the class name...

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
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