Module question - should be simple, but can't figure it out

ruby-talk
1

Say I've got a file 'dummy.rb' like this:

···

-----------------------------------------------------
module Dummy
   def TryMe
     puts "yo"
   end
end
-----------------------------------------------------

Now, I try and run this program, called 'testdummy.rb':
-----------------------------------------------------
#!/usr/bin/env ruby
require 'dummy'
include Dummy
TryMe()
def main
   TryMe()
end
main()
-----------------------------------------------------

I get, as expected:
----------
yo
----------

Now, I try and run this program, called 'testdummy2.rb':
-----------------------------------------------------
#!/usr/bin/env ruby
require 'dummy'
Dummy::TryMe()
def main
   Dummy::TryMe()
end
main()
----------------------------------------------------

I get:
-----------------
testdummy2.rb:3: undefined method `TryMe' for Dummy:Module (NoMethodError)
-----------------

Now, if I go ahead and change the 'dummy.rb' module to look like this:
----------------------------------------------------
module Dummy
   def self.TryMe
     puts "yo"
   end
end
----------------------------------------------------

testdummy2.rb gives me:
------------------------
yo
------------------------

and testdummy.rb gives me:
------------------------
testdummy.rb:4: undefined method `TryMe' for main:Object (NoMethodError)
------------------------

QUESTION: How can I create module 'Dummy' so that it can be called
either with the syntax in 'testdummy.rb' or 'testdummy2.rb' without
modification?

Thanks!
-- Glenn

2

module Dummy
  def try_me
    puts "yo"
  end
  extend self
end

include Dummy
try_me
Dummy::try_me
__END__

You just add "extend self", as above. Also it isn't a good idea to
name methods in CamelCase, as that is normally used for constants like
classes, etc. Which is why I used try_me for the method name.

Ryan

···

On 10/21/05, Glenn M. Lewis <noSpam@nospam.com> wrote:

QUESTION: How can I create module 'Dummy' so that it can be called
either with the syntax in 'testdummy.rb' or 'testdummy2.rb' without
modification?

3

[...]

Now, I try and run this program, called 'testdummy.rb':
-----------------------------------------------------
#!/usr/bin/env ruby
require 'dummy'
include Dummy
TryMe()
def main
   TryMe()
end
main()

[...]

Now, I try and run this program, called 'testdummy2.rb':
-----------------------------------------------------
#!/usr/bin/env ruby
require 'dummy'
Dummy::TryMe()
def main
   Dummy::TryMe()
end
main()
----------------------------------------------------

[...]

QUESTION: How can I create module 'Dummy' so that it can be called
either with the syntax in 'testdummy.rb' or 'testdummy2.rb' without
modification?

Option 1)
  module Dummy
     def TryMe
       puts "yo"
     end
     # Add all instance methods of the Dummy module to
     # the Dummy module object (here referenced as "self").
     extend self
  end

Option 2)
  module Dummy
     def TryMe
       puts "yo"
     end
     # give all method names (as symbols) as argument
     # to module_function
     module_function :TryMe, :SomeOtherMethod
  end

HTH,
  Stefan

···

On Friday 21 October 2005 21:06, Glenn M. Lewis wrote:

4

Couple of ways.

  module Dummy
     extend self
     def TryMe
       puts "yo"
     end
  end

This includes the Dummy module into it's own "class-level".

  module Dummy
     module_function
     def TryMe
       puts "yo"
     end
  end

This automatically creates a private class method version of the
instance method.

  module Dummy
     def self.TryMe
       puts "yo"
     end
     def TryMe
       self.class.TryMe
     end
  end

This is manual mode :wink:

T.

5

Hi --

···

On Sat, 22 Oct 2005, Ryan Leavengood wrote:

On 10/21/05, Glenn M. Lewis <noSpam@nospam.com> wrote:

QUESTION: How can I create module 'Dummy' so that it can be called
either with the syntax in 'testdummy.rb' or 'testdummy2.rb' without
modification?

module Dummy
def try_me
   puts "yo"
end
extend self
end

include Dummy
try_me
Dummy::try_me

Or:

   Dummy.try_me

(I admit I prefer the consistent use of '.' for all method calls,
regardless of what the receiver is.)

David

--
David A. Black
dblack@wobblini.net

6

Me too, I was just mimicking the OP's code (with the exclusion of the
CamelCase method name, as noted.) The double colon is much harder to
type than the period.

Ryan

···

On 10/21/05, David A. Black <dblack@wobblini.net> wrote:

Or:

   Dummy.try_me

(I admit I prefer the consistent use of '.' for all method calls,
regardless of what the receiver is.)