From: Tobias Grimm <listaccount@...>
Date: 2004-08-17T17:14:59+09:00
Subject: Re: Embedding Ruby as plugin

Joel VanderWerf wrote:

> Not sure I understand. Where is the ruby interpreter in this picture? 
> Your C++ app embeds it? Or plugin.so embeds it?

plugin.so embeds it. I can't change the C++ app, it will never know, that one of 
it's plugins uses ruby.

> What if you just set a global variable, $interface, before loading 
> rubyscript.rb, which references this global?
> 
> Is the problem then that you don't want to use a global, for the usual 
> good reasons?

No... I could live with some globals. Althought I would probably use a static 
factory method to return an Interface instance.

My problem is, that I don't know how to make my C++ classes, which are linked to 
plugin.so, available to ruby which is embedded by plugin.so.

A usal ruby extension would just load the extension from a lib. But in my case 
the lib containing the extension itself is running the ruby script

Lets say, I have interface.h which defines a C++ class "Interface" with a static 
methode that returns a singleton instance of this class. It may get the instance 
from a global variable.
SWIG now creates an interface_wrap.c, which I compile and link to my plugin.so.
Within the plugin.so some methode should now run the ruby script, calling 
ruby_init and all the stuff to handle exceptions and so on.
But how do I let the ruby script know, that there is a class "Interface"? A 
simple 'require "interface"' doesn't work.

Tobias