From: dblack@...
Date: 2006-04-11T11:12:36+09:00
Subject: Re: Identfying classes in a file dynamically

Hi --

On Tue, 11 Apr 2006, Joel VanderWerf wrote:

> 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.

Also I think that if the read-in file uses the ::Const construct,
those classes won't get counted.


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

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