Getting all classes within a module?

ruby-talk
1

hello

is there a way to get all classes defined within a module ?

something like this:

require "mymodule"
classes = mymodule.classes_within_this_module

markus

2

Markus Jais wrote:

hello

is there a way to get all classes defined within a module ?

something like this:

require “mymodule”
classes = mymodule.classes_within_this_module

         ^^^^^^^^ what is this?

In ruby, modules and files are different things, though they are often
in a one-to-one correspondence. I’ll assume that you are interested in
modules.

The following will give you all the classes defined in the scope of String.

String.constants.map {|x| String.const_get x}.grep(Class)

But this includes things like Float that are defined in Object. So let’s
define:

class Module
def my_classes
constants.map {|x| const_get x}.grep(Class)
end
end

Then you can do

String.my_classes - String.superclass.my_classes

which will be empty, unless you add a class in String:

class String
class S; end
end

after which the subtraction will return:

[String::S]

One more twist: you may also want to subtract constants that come from a
mixin module.

module Enumerable
class E
end
end

String.my_classes - String.superclass.my_classes

==> [String::S, Enumerable::E]

So let’s define:

class Module
def my_own_classes
my_classes - ancestors.map {|a|
(a == self)? : a.my_classes
}.flatten
end
end

String.my_own_classes

==> [String::S]