From: Intransition <transfire@...>
Date: 2009-12-29T23:08:50+09:00
Subject: Re: Using #include at the instance level?



On Dec 29, 3:29 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> 2009/12/29 Intransition <transf...@gmail.com>:
>
>
>
> > I would like to use #include at an instance level, such that it
> > behaves just as it does at a class level. After a number of
> > experiments I thought for sure it would work if I ran the include
> > through the object's singleton. Alas, submodules remain inaccessible,
> > eg.
>
> >  module M
> >    def m1; "m1"; end
> >    module N
> >      def self.n1; "n1"; end
> >    end
> >  end
>
> >  class X
> >    def initialize(*mods)
> >      (class << self; self; end).class_eval do
> >        include *mods
> >      end
> >    end
> >    def m ; m1 ; end
> >    def n ; N.n1 ; end
>
> Hm, this method above won't work as scope resolution rules for
> constants are different.
>
> >  end
>
> >  x = X.new(M)
> >  p x.m
> >  p x.n    #=> uninitialized constant X::N (NameError)
>
> > Is there any way to achieve this?
>
> Did you consider using #extend?
>
>  class X
>    def initialize(*mods)
>      extend *mods
>    end
> end
>
> What do you really want to achieve?  Do you have a more telling example?

It's for encapsulating test cases. Eg.

  TestCase.new(SomeClass) do
    ...
  end

Within the test case block it would help to handle #include, to make
tests less verbose.

Instead of making an instance of TestCase for each case, at this point
it looks like I'll have to create a new subclass of it.