From: Trans <transfire@...>
Date: 2007-12-14T12:28:28+09:00
Subject: Re: declaration for module methods which need to be implemented



On Dec 13, 5:30 pm, Paul <pdavi...@gmail.com> wrote:
> Let's say I have the following module:
>
> ------------------------
> module Parenting
>
>   def add_child(a_child)
>     self.children.push(a_child)
>   end
>
>   def delete_child(a_child)
>     self.children.delete(a_child)
>   end
>
>   def children
>     # need to implement
> but is there a programtaic way to declare this?
>   end
>
> end
> ------------------------
>
> Is there a way to enforce that the 'children' method is understood in
> any class which includes this module?  Or do I simply rely on a
> comment, as above

You general just make a comment in the module docs. Ie.

  # The including module must define #children.
  #
  module Parenting
    ...
  end

Under certain conditions you might provide a default, or raise an
error, eg.

  module Parenting
    def children
      raise NoMethodError
    end
  end

T.