Ruby (programming language)
Ruby has been described as a multi-paradigm programming language: it allows procedural programming (defining functions/variables outside classes makes them part of the root, 'self' Object), with object orientation (everything is an object) or functional programming (it has anonymous functions, closures, and continuations; statements all have values, and functions return the last evaluation). It has support for introspection, reflection and metaprogramming, as well as support for interpreter-based threads. Ruby features dynamic typing, and supports parametric polymorphism.
Ruby Version Manager
The entire ruby environment including the Ruby interpreter, installed RubyGems, and documentation is partitioned. A developer can then switch between the different versions to work on several projects with different version requirements. In addition to MRI, the standard Ruby interpreter, RVM functions as an installer for various other implementations of Ruby. These include JRuby, mruby, MacRuby, IronRuby, Maglev, Rubinius, Ruby Enterprise Edition, Topaz, and GoRuby (an interpreter optimized for code golf). In addition, RVM supports the installation of patched versions of MRI.