[ANN] CGenerator is now a gem

[Joel VanderWerf]

CGenerator is a framework for dynamically generating and loading C
extensions from Ruby programs. Includes CShadow module for defining
classes in terms of C structs with accessors and inheritance.

It's been in use for almost 8 years.

Installation:
gem install cgen
or download at http://rubyforge.org/projects/cgen

Example:

require 'cgen/cshadow'

class Complex < Numeric
include CShadow

shadow_attr_accessor :re => "double re"
shadow_attr_accessor :im => "double im"

def initialize re, im
self.re = re
self.im = im
end

define_c_methodabs) {
include "<math.h>"
returns "rb_float_new(sqrt(pow(shadow->re, 2) + pow(shadow->im, 2)))"
}

define_c_methodscale!) {
c_array_args {
optional :factor
default :factor => "INT2NUM(10)"
typecheck :factor => Numeric
}
body %{
shadow->re *= NUM2DBL(factor);
shadow->im *= NUM2DBL(factor);
}
returns "self"
}
end

Complex.commit

z = Complex.new 5, 1.3
p z # ==> #<Complex:0xb7dc0098 re=5.0, im=1.3>
puts z.abs # ==> 5.1662365412358
z.scale! 3.0 # float
p [z.re, z.im] # ==> [15.0, 3.9]
z.scale! 3 # int
p [z.re, z.im] # ==> [45.0, 11.7]
z.scale! # use default value
p [z.re, z.im] # ==> [450.0, 117]