Ruby: get a list of static methods

Question

I have a module Commands with several static methods defined ( self.method ). I want to get a list of methods in Commands , but instance_methods and similar methods seem to recognize only non-static methods, since the return of Commands.instance_methods is empty.

The code is as follows:

module Commands
  def self.method_1
  end

  def self.method_N
  end
end

Commands.instance_methods is empty ( [] ).

Answer 1

You can use Commands.singleton_methods in this case.

It will return array of method names.

Answer 2

When you define methods within a module or class definition using this syntax

def self.foo
  'foo'
end

you are defining a class method, not an instance method. So calling Commands.instance_methods will return empty array unless any have been defined.

To get methods defined on the class but exclude inherited methods, use:

Commands.methods(fasle)

If you don't pass false or nil you will get all instance methods including those which have been inherited.

Now if you want to get all 3 types in one shot, you could do something like:

[:methods, :instance_methods, :singleton_methods].map{|m| Commands.send(m, false)}