From: Eric Hodel <drbrain@...7.net>
Date: 2009-04-04T05:39:23+09:00
Subject: Re: Add a method as C extension to a class defined in Ruby

On Apr 3, 2009, at 09:03, Andre Nathan wrote:
> On Sat, 2009-04-04 at 00:45 +0900, Iņaki Baz Castillo wrote:
>> Hi, in case I want to add a method (using C) for a class I've created
>> in pure Ruby, must I also create the class in C?
>
> Something like this should work:
>
> static VALUE
> rb_foo(VALUE self)
> {
>    rb_p(INT2FIX(42));
>    return Qnil;
> }
>
> void
> Init_foo(void)
> {
>    VALUE klass = rb_const_get(rb_cObject, rb_intern("Foo"));
>    rb_define_method(klass, "foo", rb_foo, 0);
> }

It's better with RubyInline:

require 'rubygems'
require 'inline'

class Foo
   inline :C do |builder|
     builder.c <<-C
       void foo() {
         rb_p(INT2FIX(42));
       }
     C
   end
end

Foo.new.foo