From: Trans <transfire@...>
Date: 2007-08-03T19:37:36+09:00
Subject: Re: From method redefinition to classless Ruby.



On Aug 3, 2:25 am, "Robert Dober" <robert.do...@gmail.com> wrote:
> On 8/3/07, Trans <transf...@gmail.com> wrote:
>
>
>
> > On Aug 2, 4:43 pm, "Robert Dober" <robert.do...@gmail.com> wrote:
> > > Hi list
>
> > > Ara's post about method redefinition was extremely rich intellectual
> > > food, took some time to digest, but I just thought I share my findings
> > > with you.
>
> > Ara and Pit are impressive meta-coders indeed. Think Ara might even
> > have a Prototype lib
> > you'd enjoy.
>
> > BTW, if we were all good little scouts and always modularized our code
> > one could use:
>
> >   class Module
> >     # Prepend an "aspect" module to a module.
> >     #
> >     #   module X
> >     #     def x; "x"; end
> >     #   end
> >     #
> >     #   module U
> >     #     def x; '{' + super + '}'; end
> >     #   end
> >     #
> >     #   X.prepend U
> >     #
> >     #   X.x  # => "{x}"
>
> >     def prepend( aspect )
> >       aspect.send(:include, self)
> >       extend aspect
> >     end
> >   end
>
> > Another trick for common injuns:
>
> >   class Class
>
> >     # Prepend an "aspect" module to a class.
> >     #
> >     # class Firetruck
> >     #   def put_out_fire(option)
> >     #     "Put out #{option}"
> >     #   end
> >     # end
> >     #
> >     # module FastFiretruck
> >     #   def put_out_fire(option)
> >     #     super("very #{option}!")
> >     #   end
> >     # end
> >     #
> >     # Firetruck.prepend(FastFiretruck)
> >     #
> >     # ft = Firetruck.new
> >     # ft.put_out_fire('fast') #=> "Put out very fast!"
>
> >     def prepend( aspect )
> >       _new      = method(:new)
> >       _allocate = method(:allocate)
> >       (class << self; self; end).class_eval do
> >         define_method(:new) do |*args|
> >           o = _new.call(*args)
> >           o.extend aspect
> >           o
> >         end
> >         define_method(:allocate) do |*args|
> >           o = _allocate.call(*args)
> >           o.extend aspect
> >           o
> >         end
> >       end
> >     end
>
> >   end
>
> > Albeit that has some unfortunate shortcomings.
>
> > T.
>
> Well I do not really see these shortcomings, I'd love to have this
> mail as a comment to my blogpost BTW, would you mind?

Go for it. The shortcoming in the later example are b/c it's static
and not dynamic, ie. it happens at the time of instantiation. So it's
not a simple thing to adjust on the fly. One could make it more
flexiable, but alas the Double Module Inclusion problem gets in the
way.

> Concerning Ara's Prototype library I have seen it flying by, I will
> have a closer look, sure deserves an Exolink. But probably Ara's had
> all the fun for himself already and there is nothing left to do for me
> :(.

Not at all, I think Ara's been looking for Prototype allies :) The
only problem with prototype.rb is that it's so far removed for writing
ordinary Ruby, few are willing to embrace it --it's almost like
writing in a different language.

T.