Description

This module provides Java style interfaces for Ruby, including a fairly
similar syntax.  I don't necessarily believe in interfaces, but I wanted to
put it out there as proof that it could be done.  Frankly, Java needs mixins
more than Ruby needs interfaces, but here you go.

Installation

Manual

ruby test/ts_interface.rb
ruby install.rb

Gem Install

ruby interface.gemspec
gem install interface-<version>.gem

Synopsis

require "interface"

MyInterface = interface{
   required_methods :foo, :bar, :baz
}

# Raises an error until 'baz' is defined
class MyClass
   def foo
      puts "foo"
   end
   def bar
      puts "bar"
   end
   implements MyInterface
end

General Notes

Subinterfaces work as well.  See the test_sub.rb file under the 'test'
directory for a sample.

Developer’s Notes

A discussion on IRC with Mauricio Fernandez got us talking about traits.
During that discussion I remembered a blog entry by David Naseby.  I 
revisited his blog entry (at http://homepages.ihug.com.au/~naseby/33.html)
and took a closer look.
Keep in mind that I also happened to be thinking about Java at the moment
because of a recent job switch that involved coding in Java.  I was also
trying to figure out what the purpose of interfaces were.
As I read the first page of David Naseby's article I realized that,
whether intended or not, he had implemented a rudimentary form of interfaces
for Ruby.  When I discovered this, I talked about it some more with Mauricio
and he and I (mostly him) fleshed out the rest of the module, including some
syntax improvements.  The result is syntax and functionality that is nearly
identical to Java.
I should note that, although I am listed as the author, this was mostly the
combined work of David Naseby and Mauricio Fernandez.  I just happened to be
the guy that put it all together.

Acknowledgements

This module was largely inspired and somewhat copied from a post by
David Naseby at http://homepages.ihug.com.au/~naseby/33.html.  It was
subsequently modified almost entirely by Mauricio Fernandez through a
series of discussions on IRC.

(C) 2004 Daniel J. Berger
All rights reserved.

Warranty

This package is provided "as is" and without any express or
implied warranties, including, without limitation, the implied
warranties of merchantability and fitness for a particular purpose.

License

Ruby's

Author

Daniel J. Berger (who mostly stole it from David Naseby, which was then
modified by Mauricio Fernandez)
djberg96 at gmail dot com
imperator on IRC (irc.freenode.net)