The Fancy Programming Language
Fancy is a fully self-hosted, dynamic, pure class-based
object-oriented programming language heavily inspired by Smalltalk,
Ruby and Erlang. It supports dynamic code evaluation (as in Ruby &
Smalltalk), class-based mixins, generic pattern matching, runtime
introspection & reflection, "monkey patching" and much more. It runs
on Rubinius, the Ruby VM, and thus has first-class integration with
Ruby's core library and any additional Ruby libraries that run on
Rubinius, including most C-extensions.