From: ptkwt@...1.aracnet.com (Phil Tomson)
Date: 2003-02-22T04:03:07+09:00
Subject: Re: Ruby-swig for C struct plus methods

In article <3E562785.1080608@NASA.Gov>,
Bil Kleb  <William.L.Kleb@NASA.Gov> wrote:
>We've been playing with testing a C-code via Ruby and testunit,
>wrapping the C by hand.  We've just recently tried using SWIG to
>automate the wrapping, but so far we haven't found the right combination
>for our situation.

I've done what you're doing to unit test C++ classes.  Swig worked great 
in that case.

>
>We have C-routines that look a lot like a C++ class, i.e., a struct
>definition followed by associated methods where each method takes a
>pointer to the associated struct as the first argument.
>
>The trouble is the C SWIG generator creates a class for the struct
>and global module methods for the functions, and we've been unable
>to figure out how to get the methods mixed into the class created by
>the struct.
>
>Then again, maybe we're asking too much from SWIG's C-interface generator
>and we should just embrace the latent object-oriented design of our curent
>C code and migrate it to C++?

Swig's a great tool, but you're probably right: you're asking a lot from 
it in this case.  I would suggest moving to C++.  From my experience, Swig 
will work very nicely for wrapping your C++ classes for unit testing in 
Ruby.  

>
>Note: we'd also like to do some prototyping and possibly high-level
>orchestration in Ruby in addition to merely using the test framework.

I did exactly that on a project last summer.  We started coding in C++ and 
I wanted to be able to setup a unit testing framework for our classes.  I 
tried Cppunit but ended up using swig, Ruby and test::unit.  Since all of 
our classes were available in Ruby, we also started using Ruby for the UI 
and to parse input and configuration files - so we used C++ for the stuff 
that had to go fast and Ruby for stuff that was a lot faster to develop 
in Ruby than it would have been in C++.  The mixed language approach 
worked quite well.

Phil