From: Sean Middleditch <elanthis@...>
Date: 2001-07-17T02:46:54+09:00
Subject: [ruby-talk:17940] Re: RUBY C++ Extension

On Tue, Jul 17, 2001 at 01:54:18AM +0900, Bernhard Gl?ck wrote:
> Does anybody have the source to a WORKING C++ Class exported to RUBY
> (preferably using MSVC 6.0) ?
> I would like to instantiate my C++ classes in RUBY just the way as in
> C++ code.
> All samples and docs I found are on straigt C Extensions and that does
> not help much.

I dunno how other people do it, but I wrap the C++ calls in C functions.
Pass the C++ class pointer along with the Ruby object, cast it in the C
function, and have it call the proper C++ method.

I'm jsut beginning to get Ruby integrated as a scripting language in
AweMUD, http://awemud.sourceforge.net if you want a simple example of
this, although that code needs to be finished and heavily cleaned up.

> 
> Also how can I export the overloaded operators (for addition etc..) 
> And very important can i mirror an inheritance relationship in RUBY ?
> say i have a Ruby Method 
> world_add( Object ) which takes an object.. Object is a C++ Class. Now
> i have a C++ class which is derived from Object. How do i export it to
> Ruby so that the world_add method treats it just like the Object base
> class ? This is pretty important to me.

If I understand what you want, just wrap the C++ operators and calls in
the C functions. Pass the derived object into the Ruby class, and the C
function can cast it and call whatever method - using polymorphism
everything should work fine.  That's more or less how Ruby handles the
Entity/Object/Character class in AweMUD.

> Also my progam consists of more than one DLL in the main DLL i would
> like to export the Object Base Class to ruby and in some plugin DLLs i
> would like to export only classes derived from Object which can then
> be added to a world with world_add ? DOes that work ? Over the DLL
> boundary ? What to do to make it workt ?

I'm a UNIX person, no clue there.  Works in Linux shared objects, though.

> Thanks in advance
> Bernhard Gl?ck