From: Gabriel Saravia <gabe.saravia@...>
Date: 2009-05-07T18:11:33+09:00
Subject: Re: Adding a =~ method to the Method class

Thank you for the quick response!

To answer the other post about an example, The particular use I have for 
it was that I had an abstract class deriving from ActiveRecord.  It made 
sense to override many of ActiveRecord's class methods: The 
AbstractClass methods are passed some params in addition to those 
standard to the ActiveRecord method, which it then uses those params to 
delegate onto the correct concrete sub class, to which it passes the 
standard ActiveRecord params.  However, in the subclasses of this 
abstract class, I re-instate the ActiveRecord class methods.

So, in order to test that I had actually reinstated the ActiveRecord 
methods, I needed to assert that my concrete sub class was using the 
ActiveRecord method and not the abstract one.

so...

!(MyAbstractClass.method(:find) == ActiveRecord::Base.method(:find))

but,

MyConcreteSubclass.method(:find) =~ ActiveRecord::Base.method(:find)

incidentally, since posting I attempted to go to bed, but couldn't, kept 
on thinking about the problem, when I remembered vaguely about unbound 
methods and came up with this purely ruby method solution:

  def test_class_methods_similar(klass1, klass2, method_name_symbol)
    unbound_method1 = klass1.method(method_name_symbol).unbind
    unbound_method2 = klass2.method(method_name_symbol).unbind
    unbound_method1 == unbound_method2
  end

The importance of the test truly came out when it helped me catch a bug 
- I had overwritten many methods, and had accidentally overwritten 
destroy with destroy_all.

however, I like the posted solutions better for readability and the fact 
that it can be called directly from a class.

and, did that post really come from matz?  I ask because seeing as how 
I'm fairly new, (to Ruby, to Rails, etc.) and this is my first post ever 
to the Ruby forum, I'm feeling a slight sense of awe. just want to say, 
Ruby is a beautiful language.  It has made me love programming after 
many of my college courses had pretty much destroyed any such thought.

I must ask, any chance Method.=~ could make it into the Ruby codebase? 
I figure it must have a lot more uses whenever a solution involves 
overriding/passing around methods between classes, including most any 
use of alias_method?

-Gabe

KDr2 wrote:
> *ruby-1.8.7-p160*
> add to *eval.c,* after line *9323*:
> 
> static VALUE
> method_similar(method, other)
>     VALUE method, other;
> {
>     struct METHOD *m1, *m2;
> 
>     if (TYPE(other) != T_DATA || RDATA(other)->dmark !=
> (RUBY_DATA_FUNC)bm_mark)
>   return Qfalse;
>     if (CLASS_OF(method) != CLASS_OF(other))
>   return Qfalse;
> 
>     Data_Get_Struct(method, struct METHOD, m1);
>     Data_Get_Struct(other, struct METHOD, m2);
> 
>     if (m1->klass != m2->klass || m1->rklass != m2->rklass ||m1->body !=
> m2->body)
>   return Qfalse;
> 
>     return Qtrue;
> }
> 
> add to *eval.c* affter line *10046*:
> 
> rb_define_method(rb_cMethod, "=~", method_similar, 1);

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