From: Daniel Berger <djberg96@...>
Date: 2002-05-12T06:45:05+09:00
Subject: Re: Ruby extensions - pushing classes into other modules

ts wrote:
>>>>>>"D" == Daniel Berger <djberg96@attbi.com> writes:
>>>>>>
> 
> D> I want to create a base class called "Sys" that would simply serve as a 
>                            ^^^^^
>                            module, no ?

Oops.  Yes, right.

> 
> D> would not only help reduce serious bloat in one file, it would allow 
> D> others to easily add their own extensions under the 'Sys' namespace.
> 
>  Now if I want to extend the Sys namespace with my private class Sys::Own,
>  I'll write in the file own.c
> 
>    void Init_own()
>    {
>       VALUE sys_mSys, own_cOwn;
>       rb_require("sys");
>       sys_mSys = rb_const_get(rb_cObject, rb_intern("Sys"));
>       own_cOwn = rb_define_class_under(sys_mSys, "Own", rb_cObject);
>       /* ... */
>    }

I took this approach first, since I figured it was only fair that I make 
my modules the way everyone else will have to. :)

Here's the file - Yes, I know it's silly to have one method - I'm just 
testing. :)

/* Sys.c */
#include "ruby.h"

#ifdef __cplusplus
extern "C"
#endif

VALUE mSys;

void Init_Sys()
{
    mSys = rb_define_module("Sys");
}

////////////////////////////////////////

/* Info.c */
#include "ruby.h"
#include <unistd.h>

#ifdef __cplusplus
extern "C"
#endif

#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 256
#endif

VALUE mSys, cInfo;

static VALUE sys_info_hostname()
{
    char h[MAXHOSTNAMELEN];
    int rv;

    rv = gethostname(h,MAXHOSTNAMELEN);
    return rb_str_new2(h);
}

void Init_Info()
{

    rb_require("Sys");
    mSys = rb_const_get(rb_cObject,rb_intern("Sys"));
    cInfo = rb_define_class_under(mSys,"Info",rb_cObject);

    rb_define_module_function(cInfo,"hostname",sys_info_hostname,0);
}


It makes fine, but when I try this:

require 'Sys'
puts Sys::Info.hostname

I get this error:

../test.rb:9: uninitialized constant Info at Sys (NameError)

Am I just building it wrong?  I built Sys first, then Inf with a simple 
"create_makefile" command, separately.

Thanks.

Dan