Is it possible to make an alias for a module in Ru

In Python, you can set an alias for a module with 'as':

import mymodule as mm

But I can't seem to find an equivalent for ruby. I know that you can include rather than require a module, but this risks namespace collisions. Is there any equivalent to Python module aliases?

回答1:

Modules in Ruby aren't really that special, so you can just assign them to another constant:

[4] (pry) main: 0> module TestModule
[4] (pry) main: 0*   def self.foo
[4] (pry) main: 0*     "test"
[4] (pry) main: 0*   end  
[4] (pry) main: 0* end  
=> nil
[5] (pry) main: 0> tm = TestModule
=> TestModule
[6] (pry) main: 0> tm.foo
=> "test"

回答2:

Michael's answer seems to solve your question... still, I read the question a bit differently and discovered something really nice that I thought worth sharing.

I understood your question as: "What do I do if I want to require two modules of the same name?", that is, how could I alias them if requiring both would result in a namespace clash? Because, as far as my understanding of Python's 'import ... as ...' goes, it also solves those kinds of problems. An example in Ruby:

#file a.rb
module A
  def self.greet
    puts 'A'
  end
end

#file b.rb
module A
  def self.greet
    puts 'other A'
  end
end

Now if I would do this in a third file:

require_relative 'a'
require_relative 'b'

A.greet # => other A

the first A would be completely overridden by the A in b.rb. Using Michael's trick also won't help:

require_relative 'a'
TMP_A = A
A.greet # => A
TMP_A.greet # => A
require_relative 'b'
TMP_A2 = A
A.greet # => other A
TMP_A2.greet # => other A
TMP_A.greet # => other A :(

Too bad. Then I thought, well, in Ruby there's the ubiquitous dup for making a clone of basically everything and without too much hope I just typed this and reran the program:

require_relative 'a'
TMP_A = A.dup
A.greet # => A
TMP_A.greet # => A
require_relative 'b'
TMP_A2 = A
A.greet # => other A
TMP_A2.greet # => other A
TMP_A.greet # => A :P

That totally made my day, hope you guys appreciate it as much as well. Now that I think about it, it makes sense - a module is an object like any other after all, so why shouldn't dup work?