From: Daniel Carrera <dcarrera@...>
Date: 2003-01-25T07:59:35+09:00
Subject: Ruby Modules in C

I'm struggling to write a module, with a method, in C.

With plain Ruby, I would do something like this:

>> module M
>>   def M.five
>>     return 5
>>   end
>> end
=> nil
>> M.five
=> 5

So I thought that, in C, I could write:

#include "science.h"

static VALUE mScience_seven(VALUE self) {  return rb_float_new(7); }

VALUE mScience;

void Init_science() {         /* Module definition */
  mScience = rb_define_module("Science");

  mScience_define_constants();
  rb_define_method(mScience, "Science.seven", mScience_seven, 0);
}

The module itself builds, and I can access the constants fine.  But the 
method is giving me trouble:

>> require 'science' 
=> true
>> Science::SOLAR_MASS
=> 1.98892e+30
>> Science.seven 
NameError: undefined method `seven' for Science:Module
        from (irb):3
>>

I've also tried  rb_define_method(..."seven"...), but that didn't work 
either.

Does anyone know how I can write module methods in C?

Thanks.

-- 
Daniel Carrera
Graduate Teaching Assistant.  Math Dept.
University of Maryland.  (301) 405-5137