Question

Hey everyone! I am having trouble with understanding modules — I have two files, one named “modfile.rb” with the module, and one named “main.rb” that runs the code:

# modfile.rb  
module Module1
  def method1
    puts "SUCCESS!"
  end
end

# main.rb  
require 'modfile'
Module1.method1

Unfortunately, instead of SUCCESS! appearing on my screen, I get this:

<internal:lib/rubygems/custom_require>:29:in 'require': no such file to load -- modfile (LoadError)
  from <internal:lib/rubygems/custom_require>:29:in 'require'
  from main.rb:1:in '<main>'

I think (though I may be wrong) that Ruby is looking to the lib/…. file inside the Ruby directory on my computer, while modfile.rb is saved in the same directory as main.rb. How do I fix this problem (other than by moving the module’s file?)

PS. one guide suggested I add the line “require ‘rubygems'” but I already did and got the same error.

Answer 1

If modfile.rb and main.rb are in the same directory, make sure that you aare calling main.rb from the directory it’s in, ie:

ruby main.rb

As I believe that is the directory that the Ruby interpreter will be looking in for any require files.

Edit: as @the-tin-man points out, the behaviour has changed for Ruby 1.9.

To be completely on the safe side, you can do:

require File.join(File.dirname(__FILE__), "modfile")

One other thing:

def method1

… should be:

def self.method1

… since you are calling the method as a class level method.