From: Joel VanderWerf <vjoel@...>
Date: 2007-09-23T04:08:36+09:00
Subject: Re: [ANN] CplusRuby - Gluing C and Ruby

Michael Neumann wrote:
> Hi all,
> 
> I am proud to announce my latest project called CplusRuby.
> Below I pasted it's README for further explanation.
> Alternatively read the following blog article:
> 
> http://www.ntecs.de/blog/articles/2007/09/21/cplusruby-gluing-c-and-ruby
> 
> ----------------------------------------------
> CplusRuby - Glue C and Ruby together (OO-like)
> ----------------------------------------------

It's been done, but I'm glad to see it done again and probably with new 
ideas :)

For comparison:

   require 'cgen/cshadow' # from cgen on RAA

   class NeuralEntity
     include CShadow
     attr_accessor :id
   end

   class Neuron < NeuralEntity
     shadow_attr_accessor :potential       => "double potential"
     shadow_attr_accessor :last_spike_time => "double last_spike_time"
     shadow_attr_accessor :pre_synapses    => Object

     define_c_method :stimulate do
       arguments :at, :weight
       body %{
         shadow->potential += NUM2DBL(at)*NUM2DBL(weight);
       }
     end

     def initialize
       self.pre_synapses = []
     end
   end

   NeuralEntity.commit # generate and load the shared lib

   if __FILE__ == $0
     n = Neuron.new
     n.id = "n1"
     n.potential = 1.0
     n.stimulate(1.0, 2.0)
     p n.potential # => 3.0
   end

Cgen is middle aged, as ruby libraries go (written mostly in 2001), and 
it probably isn't up to community standards in a number of ways. Still, 
I've used it intensively in numerical and hybrid simulation since then. 
It's the foundation for redshift, which is a DSL for simulation of 
hybrid automata (networked state machines with continuous as well as 
discrete dynamics).

Cgen/cshadow handles a number of issues for you:

- creating accessors (r, w, rw)
- type checking and conversion in the write accessor
- mark and free functions
- attr initialization
- persistence via marshal and yaml (or an attr may be specified 
non-persistent)
- extensible attribute classes for defining new attr types, other than 
the basic numeric, string, and Ruby object types
- inheritance (a subclass of a shadow class inherits the parent's shadow 
attrs in its own C struct; struct may be safely cast to parent type)
- tools for managing how code is distributed among files (very important 
with a large project, or else recompilation time gets painful).
- tools for managing declarations and preprocessor includes
- DSL for rb_scan_args()

This is pretty well documented, though it is in the old rd format, 
rather than rdoc.

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407