From: Erik Veenstra <pan@...>
Date: 2006-02-09T01:43:21+09:00
Subject: Re: Meta-Meta-Programming

>  def def_types(*types)
>    wrap_module_method(:method_added) do |org_method, args, block|
>      if types
>        method_name     = args[0]
>        t               = types
>        types           = nil   # Avoid looping
>        typed(method_name, *t)
>      end
>
>      org_method.call(*args, &block)    if org_method
>    end
>  end
>
> Since we do a "wrap_module_method" in "method_added" and
> "wrap_module_method" does a "wrap_method" and "wrap_method"
> adds a method and thus does a "method_added", the wrapped
> "method_added" gets called over and over again. That's why I
> introduced this loop-avoiding-system. You only have to add
> this mechanism when wrapping Module#method_added, not for
> other module methods.

A bit more readable:

"def_types" wraps "method_added."

From now on, every time "method_added" is called, it calls
"typed" (if we remove "if types"), which calls "wrap_method,"
which adds methods and thus triggers "method_added." And so on.

This "types = nil", also applies the wrapping to *only* the
next method (only to Foo#bar1 and not to Foo#bar2).

gegroet,
Erik V. - http://www.erikveen.dds.nl/