From: Daniel Brockman <daniel@...>
Date: 2005-07-20T00:23:46+09:00
Subject: Re: Ruby/Rails as a starter language?

Mark Volkmann <r.mark.volkmann@gmail.com> writes:

> On 7/19/05, Stefan Lang <langstefan@gmx.at> wrote:
>
>> There are no static methods in Ruby
>> (there is always a "self")
>
> Is there some difference between what is called a "class
> method" in Ruby and what is called a "static method" in
> Java?  They seem the same to me.

In Ruby, “class methods” aren't static — they are dispatched
on the receiver like other methods and are thus polymorphic.

   class Moomin {
     public static int foo() { return 123; }
   }

   Moomin.foo(); //=> 123

That method isn't really a method.  It's just a function,
because it doesn't have a receiver.  The above Java code is
equivalent to the below C code:

   int Moomin_foo (void) { return 123; }

So Moomin is not the receiver — it's just the namespace.
Now look at this Ruby code:

   class Snufkin
     def self.foo ; 123 end
   end

   Snufkin.foo #=> 123

Here, Snufkin is an object and ‘foo’ is a method.  It works
just like any other method invocation in Ruby.  To see where
this matters, try to reproduce the below code in Java:

   def polymorph(snufkin)
     snufkin.foo
   end

   polymorph Snufkin #=> 123

   class Snork
     def self.foo ; 456 end
   end

   polymorph Snork #=> 456

-- 
Daniel Brockman <daniel@brockman.se>

    So really, we all have to ask ourselves:
    Am I waiting for RMS to do this?   --TTN.