From: Robert Klemme <bob.news@...>
Date: 2004-08-09T23:16:26+09:00
Subject: Re: stupid question: Object#name


"Benny" <linux@marcrenearns.de> schrieb im Newsbeitrag
news:2npdjuF3728iU1@uni-berlin.de...
> ok after rethinking I have to correct me:
> substitute Object#name with Object#names
> in my first posting

No good.  Benny, I seriously think you should get rid of the idea that
variable identifiers are an object's names.

> I think in the kernel we have symbols attached to object-ids (do we?)

Nope.  The association between variable names and objects is contained in
the current binding (for local variables, that is).  It's a different
story for instance variables.

>> def test; foo = Foo.new; p foo; b = binding; p( eval("foo", b)); end
=> nil
>> test
#<Foo:0x101831c0>
#<Foo:0x101831c0>
=> nil

> so why not have a method to show us the symbols to a corresponding
> object_id?

It's a one way street.  You can only walk it in the direction of varible
to instance, not the other way.  It's not needed and it would be a total
overhead to manage this at runtime.

> >> btw. why didn't matz make Class and Object be the same thing?
> >
> > In which context? If he did Ruby would be a prototype-based language
> > where the only way to build similar Objects is to have a template
object
> > which you clone.
> but I thought we would have some: the class Object (since its a class
its
> also an object in ruby) or did I get you wrong (I must admit I have no
idea
> of the formal meaning / definition of �prototype-based language�)

As I said earlier, you got stuck in the self referentiality.  Object is a
class and class in turn is an object, too.

> > BTW, what are you wanting that .name method for? If it is for
debugging
> > reasons there might be another way of doing it.
> you mean Kernel#caller, right? :)
> so its simply comfortable if you can use
>
> name = MyClass.new(params)
>
> instead of
>
> name = MyClass.new(name, params)
>
> the last one is doubled effort and if you accidently choose
> different names for the object and the content of the name-attribut
> you may later on have to remember 2 different names or fix it.
> it may also be confusing.

Of course.

> (I like to iterate over all objects of a class and often I need the name
of
> the object in the iteration to identify the current thing.

No, you don't need the var name for that.  You can always do

foo = Foo.new

ObjectSpace.each_object( Foo ) do |obj|
  if obj.equal? foo
    puts "found it"
  else
    puts "other instance"
  end
end

http://www.ruby-doc.org/core/classes/Object.html#M000899


> in the iteration I like to invoke certain methods, so in the end they
are
> processed on every object of that class)

You're making me curios why you need that and what you do.

Kind regards

    robert