From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2002-08-04T12:36:46+09:00
Subject: Re: embed or swig?

In article <20020803231558.GA11531@prism.localnet>,
Massimiliano Mirra  <list@NOSPAMchromatic-harp.com> wrote:
>On Sun, Aug 04, 2002 at 07:56:21AM +0900, Phil Tomson wrote:
>> We started off wanting to do unit testing of our C++ classes so I tried 
>> out Swig1.3.13 to wrap our classes.  Let's say you have three classes, 
>> we'll call them Line, Polygon and Point and let's say you want to have 
>> them live in a namespace called Geo.  You would define an interface file 
>> as an input to swig that would looks something like:
>> 
>> %module Geo 
>> %{
>> #include "Line.h";
>> #include "Polygon.h";
>> #include "Point.h";
>> %}
>> %include "Line.h";
>> %include "Polygon.h";
>> %include "Point.h";
>> 
>> //end of Geo.i (probably not completely right, I'm doing from
>> memory)
>
>Wait a minute.  Do you really mean that, after you've written your C++
>classes, you just feed nine lines to Swig and after some crunching you
>
>have them available in Ruby?  Or are you just simplifying?
>

Well, that is a bit simplified, though there are cases where that would 
probably be true.

In reality you'll probaby have to write some typemaps - In the example 
above I show the the constructor for Geo::Polygon is taking a Ruby array 
of Lines - you'd probably have to write a typemape for that.

Also, C++ allows method names to be overloaded based on differing argument 
lists, Ruby doesn't so you would have to use swig's %rename (see the docs 
for details).  But other than that swig is actually pretty easy to use.

Phil