Question

Is it possible to get rid of the eval statement below? The code below filters out all classes which are derived from type BaseClass. Afterwards those classes are instantiated and method ‘hello’ is called.

module MySpace    class BaseClass     def hello; print '\nhello world'; end   end    class A<BaseClass     def hello; super; print ', class A was here'; end   end    class B<BaseClass     def hello; super; print ', I'm just a noisy class'; end   end    MySpace.constants.each do | e |     c=eval(e)     if c < BaseClass       c.new.hello     end   end  end 

So after execution the output is:

hello world, I’m just a noisy class
hello world, class A was here

I think unnecessary use of eval is evil. And I’m not sure if the use of eval is mandatory here. Is there is a smarter way in invoking all classes from type ‘BaseClass’ dynamically?

Answer 1

c = MySpace.const_get(e)