From: Nickolay Kolev <nmkolev@...>
Date: 2005-07-31T16:36:22+09:00
Subject: Higher Order Functions

Hi guys,

I have recently started learning Ruby having some background in  
Python and Prolog. Being a fan of functional programming I want to  
port the goopy functions (http://goog-goopy.sourceforge.net/ 
goopy.functional.html) in Ruby despite most of them having  
straightforward equivalents in Ruby already. Just as an exercise. I  
also saw it as a good way to teach myself about modules. And  
eventually about unit testing. :-)

My plan is to put all the functions in a module called Functional and  
call them like Functional.func_name(params).

in fruby.rb:

module Functional

   def Functional.every(f, lst)
     lst.collect { |element| f(element) }
   end

end

in test.rb:

require 'fruby'

def times_two(x)
     x * 2
end

p Functional.every(:times_two, [1,2,3])


And I get this:

undefined method `f' for Functional:Module (NoMethodError)

How do I pass the times_two function to the module method?

Many thanks in advance!

-- Nicky