How can I call Rake methods from a module - ruby

Question

I have a lot of utility functions in my rake files, some of which create rake tasks. I want to move these utility functions into a module to avoid name clashes, but when I do the rake methods are no longer available.
require 'rake'
directory 'exampledir1'
module RakeUtilityFunctions
module_function
def createdirtask dirname
directory dirname
end
end
['test1', 'test2', 'test3'].each { |dirname|
RakeUtilityFunctions::createdirtask dirname
}
The error I get is:
$ rake
rake aborted!
undefined method `directory' for RakeUtilityFunctions:Module
C:/dev/rakefile.rb:8:in `createdirtask'
C:/dev/rakefile.rb:13:in `block in <top (required)>'
C:/dev/rakefile.rb:12:in `each'
C:/dev/rakefile.rb:12:in `<top (required)>'
As far as I can tell the directory method is placed on the ruby top-level by the following code in Rake:
# Extend the main object with the DSL commands. This allows top-level
# calls to task, etc. to work from a Rakefile without polluting the
# object inheritance tree.
self.extend Rake::DSL
Is there a simple way of call functions that have been placed on the top-level like this?

Answer 1

When you define a Module, the code within that module has a new scope.
So directory within RakeUtilityFunctions is in a different scope to the top-level code.
As you haven't defined directory within RakeUtilityFunctions you get an undefined method error.
Have a look at the Scope Gate section of this article.

Answer 2

I have figured it out now. With help from #ReggieB, I discovered this question: ways to define a global method in ruby.
It contained an excerpt from the rake change log.
If you need to call 'task :xzy' inside your class, include Rake::DSL into the class.
So, the easiest way to do this is to extend the module with Rake::DSL:
require 'rake'
directory 'exampledir1'
module RakeUtilityFunctions
self.extend Rake::DSL ### This line fixes the problem!
module_function
def createdirtask dirname
directory dirname
end
end
['test1', 'test2', 'test3'].each { |dirname|
RakeUtilityFunctions.createdirtask dirname
}