From: Joel VanderWerf <vjoel@...>
Date: 2006-04-11T10:27:35+09:00
Subject: Re: Identfying classes in a file dynamically

Navya Amerineni wrote:
> Hi,
> 
> I was trying to identify the classes in a give file at the run time. the following is the code i used.
> sc, ec = [], []
> ObjectSpace.each_object(Class) { |c| sc << c }
> require 'Roman.rb'
> ObjectSpace.each_object(Class) { |c| ec << c }
> new_classes = ec - sc
> puts new_classes
> sc, ec = [], []
>  ObjectSpace.each_object(Class) { |c| sc << c }
>  require 'Roman1.rb'
>  ObjectSpace.each_object(Class) { |c| ec << c }
>  new_classes = ec - sc
> puts new_classes
>  
> Both roman.rb and roman1.rb has the same class Roman.
> the first time i print the new_classes i can see the Roman class in the output but the second one does not print because the class Roman is arleady read previously.
> 
> is there a way i can over come this problem and identify the Roman class twice.

One way is to wrap the file in a module, so that the constants defined
in it will not collide with other constants.

file = "some/file"
m = Module.new
m.module_eval(IO.read(file), File.expand_path(file))
p m.constants

But then the Roman module won't be available except as m::Roman. To fix
this, you could include m into any class or module that needs to use Roman.

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407