From: Its Me <itsme213@...>
Date: 2004-02-28T02:34:47+09:00
Subject: Re: Extensible meta-data ?


"Robert Klemme" <bob.news@gmx.net> wrote...
>
> > And then use this:
> > class Mine; end meta ... # metadata on Mine
>
> I don't think this will work since class...end doesn't return the class.

Correct. I know I could stick in a "self" before the end to make it work,
but am very curious why it does not return the class. Similarly, I am very
curious why def...end does not return a useful object (UnboundMethod? Proc?
I'm not a guru, but "nil" is not an intuitive return to me).

> > class Mine
> >    def foo; end meta ...  # metadata on Mine#foo
> > end
> >
> > Thoughts? Am I trying to do something ridiculous?
>
> How about this:
>
> class Module
>   def meta(*args)
>     case args.size
>       when 0
>         meta_data[self]
>       when 1
>         if args[0].kind_of? Hash
>           meta_data[self].update args[0]
>         else
>           meta_data[args[0]]
>         end
>       when 2
>         meta_data[args[0]].update args[1]
>       else
>         raise ArgumentError, "Wrong number of args"
>     end
>   end
>
>   def meta_data
>     @meta ||= Hash.new {|h,k| h[k] = {}}
>   end
> end
>
> class Foo
>   def foo; puts "bar"; end
>   meta :foo, "method" => "metadata", "foo" => "bar"
>   meta "class" => "metadata", "foo" => "bar"
> end
>
> p Foo.meta :foo
> p Foo.meta

I really want to attach Method meta-data to the Method, not to the class. If
I can't figure out how to get a handle on the method object, then perhaps
I'll do something like this.

Thanks for the code; always amazes me how others' experience shows in much
more efficient coding styles than my own :)