From: emilie3012@... (Steve Hart)
Date: 2003-04-11T00:24:55+09:00
Subject: Re: embedding ruby

"Simon Strandgaard" <0bz63fz3m1qt3001@sneakemail.com> wrote in message news:<pan.2003.04.09.11.06.37.642046@sneakemail.com>...
> On Tue, 08 Apr 2003 19:56:33 +0000, Steve Hart wrote:
> 
> > The scripts are loaded into a stack within my c++ code
> > I have a c++ class 'GMScript' and have used swig to wrap into ruby
> > I use a ruby script that inherits this class
> > i.e.
> > class Test1 < Gm::GMScript
> > 
> >         def initialize(sg,p1,p2)
> > 
> >                 super(sg,p1,p2)
> > 
> >                 @object1 = Gm::GMObjectNode.new("object1")
> >         end
> >         .
> >         .
> >         .
> > end
> 
> I had some trouble with extending a SWIG-class, it resulted 
> in a exception: nameerror. 
> You are using inheiritance, no problems here.
> 
>  
> > in c++ I call at start
> > 
> >         ruby_init();
> >         ruby_init_loadpath();
> >         ruby_script("embedded");
> >         rb_require("gm.so");            - swigged up wrapper lib
> 
> Look fine.
> 
>  
> > then each time a script load is requested i do the following (protect
> > code removed for clarity)
> > 
> >         rb_load_protect(rb_str_new2("Test1.rb"),Qfalse,&state);
> > 
> > then
> >         oClass = rb_const_get(rb_cObject, rb_intern("Test1"));
> >         scriptObject = rb_funcall(oClass, rb_intern("new"), 
> >                                   3,sgValue,pathName,className);
> >         Data_Get_Struct(scriptObject,GMScript,scriptPtr);
> >         scriptPtr->obj = scriptObject;
> 
> This code could be the problem. 
> * bootstrapping of your swig class.
> * you are not registering scriptObject, so GC won't know that its
>   in usage and thus thinks it must get killed. 
>   
> How does your SWIG interface file look like ???
> If it includes a .H file how does it look like ???
> 
> 
> > The problem is that as I load more scripts previous scripts get freed
> > of by the GC. In addition, the GMObjectNode's created within the
> > Scripts are also freed. 
> 
> Sounds like you object is holding ruby-childen. 
> You will need to do rb_mark on thise.
> 
> 
> > What I want to do is only free off the Script
> > when the user deletes it
> > from the script stack and decide at this time if the GMObjectNode
> > should
> > also be deleted. I assumed that since the scriptObject is stored
> > within the C code the GC would not free these off (or is it because
> > the scriptObject is stored in GMScript superclass itself. 
> 
> Wrong assumption. It depends on wheter or not you have registered
> your scriptObject.
> 
> 
> > I cannot
> > mark the object since this is under the control of Swig. I have tried
> > 
> >         rb_global_variable(&scriptObject)
> > 
> > but this does not prevent the freeing and in addition crashes the
> > program with an error:
> 
> How did you "try" it ???
> 
> 
> Read my text on embedding, look at the tar.gz file :-)
> http://metaeditor.sourceforge.net/embed/
this thread carries on in 'embedding ruby with swig'