From: nobu.nokada@...
Date: 2001-12-28T08:59:24+09:00
Subject: [ruby-talk:29492] Re: Module#included

Hi,

At Fri, 28 Dec 2001 06:24:12 +0900,
Bob Hutchison <hutch@xampl.com> wrote:
> It takes one argument that I know of, the new module that is including this
> module. Are there other arguments? (I don't think so, guessing from the call
> to rb_define_private_method in object.c -- the last argument is 1 which is
> called argc in the method's definition in class.c).

Nothing more.

> When is this called? before or after the method is included? what is the
> state of the module being defined when this method is called? I think it is
> called before the module is included.

After Module#append_features.

> Is there a recommended way to obtain some data from the new module (the one
> including this module). For example, I'd like to set up a hash that maps a
> string to the new module, but only if it is defined. The trouble is that I
> cannot use the included module to define default values (it seems, and this
> is why I think the method is called before the module is included). I am
> forced to trap an exception if the string is not defined in the new module
> -- this works, but...

The argument passed to Module#included is the new module
itself.

$ cat tmp.rb
module M
  def M.included(c)
    puts "M included by #{c}"
    c.new.m			# works already
  end
  def m
    puts self
  end
end

class C
  include M
end

$ ruby tmp.rb
M included by C
#<C:0x402d2d10>


Nobu Nakada