hacks/safe_mixin

class Module < Object

A hack that allows mixins to only be mixed in to classes that have the specified methods defined. Note that this requires that the 'include' appear at the end of the class definition (after all the methods have been defined).

Example:

  module Foo
    mixin_requires :foo, :bar
    def xyz
      # If foo and bar are not defined in the derived class, then this will
      # raise an exception, so it's best to know that this won't work at
      # load-time.
      foo
      bar
    end
  end
  class Bar
    def foo
      puts "foo"
    end
    def bar
      puts "bar"
    end
    # This must come last, because foo and bar must be defined before
    # including Foo.  If they are not defined, then an exception will be
    # thrown.
    include Foo
  end

Public Methods

mixin_requires(*args)

Require that the class/module that a mixin is being included in MUST define certain methods.

args	A list of Symbols and Integers. When a Sybmbol, indicates the given method must be defined. When an Integer, indicates the desired arity of the method indicated by the previous Symbol.

arity_matches(actual_arity, desired_arity)

Requires