From: transfire@...
Date: 2006-07-22T23:40:27+09:00
Subject: Re: Meta-Meta-Programming, revisited


Erik Veenstra wrote:
> > Sorry, I misprepresnted what I meant. Use "aModule" instead
> > of "Module". -- You created a special method:
> > #wrap_module_method for doing #wrap_method external to the a
> > module/class, but you could just make it public (or use
> > send):
> >
> >   aModule.wrap_method
>
> Wrong!... ;] The receiver of wrap_method is *always* a
> module/class. When wrapping an instance method, with
> wrap_method, the receiver is a module. When wrapping a module
> method, with wrap_module_method, the receiver is the singleton
> class of that module.
>
> So, you should write aModule.meta_class.wrap_method (using
> Why's little meta library...). Or, in default Ruby:
>
 >  class << aModule
>    self
>  end.instance_eval
>    wrap_method(method_name){...}
>  end
>
> I don't want to see this in regular, every day Ruby code.
> That's why I came up with this wrap_module_method and this
> stupid Module argument thing. ;] Kind of shortcuts...

Well, that's the thing. I'd rather do

  aModule.meta.wrap_method
  aModule.meta.pre_condition

Then have all these different useage forms:

  wrap_method
  wrap_module_method
  pre_condition( aModule,

T.

> > >  * When wrapping methods in both the class and the superclass,
> > >    going up and down, you can't (at wrap-time) determine the
> > >    order in which the blocks are to be executed (at run-time).
> > >    If I run the code below with your wrap_method (after removing
> > >    the "method does not exist" check), this :wrap_Foo is gone!
> > >    It's not what _I_ expected... ;] (See [1] for a more
> > >    complicated example. I'll try to make a diagram.)
> >
> > Owww! Nice catch. I hadn't though of that.
>
> ;]

On looking at it again, I think it goes back to you wnating to wrap
methods that aren;t there. When subclass, there's not much use in
wrapping when one can just define the method and call super.

> Sure. Everybody is free to copy the code and use it for
> whatever reason. If you make money with it, please call me...

Money? Don't make it.

T.