From: nobu.nokada@...
Date: 2002-04-23T17:51:32+09:00
Subject: Re: building extensions-- new vs initialize

Hi,

At Tue, 23 Apr 2002 10:09:52 +0900,
Norman Makoto Su wrote:
> Hi, I'm trying to build a ruby extension in C.  While looking at the pickaxe CD
> player example, I noticed that they define a singleton_method called "new" and
> then a normal method called "initialize".  What is the motivation for this?  Is
> it so that when you call CDPlayer.new, the returned object is of type Data?
> (this can't be achieved with just initialize?)

In general, redefinition of "new" will be deprecated in 1.8.
Instead, you have to do are:

(1) define "allocate" class method,
(2) define "initialize" instance method,
(3) call rb_call_super() in "initialize", and
(4) call rb_enable_super() for "initialize" in Init_xxx().

Although 3 and 4 are not necessary, I recommend them.  I hope
rough/ext/stringio.c to be an example.

> I'm confused as to when it is or not neccessary to define a "new" method in
> addition to an "initialize" method.  For example, when defining class variables,
> does this have to be done in a "new" method, since the class has not been
> instantiated?

No, once defined a class, you can define class variables
whenever.  Typically in the Init function, "new" is called for
each object, however class variables are singleton.

-- 
Nobu Nakada