implementations (may only be useful for numerical code). Topaz, a Ruby implementation written in Python Opal, a web-based interpreter that compiles Ruby to JavaScript Other now defunct Ruby implementations were: MacRuby, a Mac OS X implementation on the Objective-C runtime. Its iOS counterpart is called RubyMotion IronRuby an implementation on the .NET Framework Cardinal, an implementation for the Parrot virtual machine Ruby Enterprise Edition, often shortened to ree, an implementation optimized to handle large-scale Ruby on Rails projects HotRuby, a JavaScript and ActionScript implementation of the Ruby programming language The maturity of Ruby implementations tends to be measured by their ability to run the Ruby on Rails (Rails) framework, because it is complex to implement and uses many Ruby-specific features. The point when a particular implementation achieves this goal is called "the Rails singularity". The reference implementation, JRuby, and Rubinius are all able to run Rails unmodified in a production environment. Platform support Matsumoto originally developed Ruby on the 4.3BSD-based Sony NEWS-OS 3.x, but later migrated his work to SunOS 4.x, and finally to Linux. By 1999, Ruby was known to work across many different operating systems. Modern Ruby versions and implementations are available on all major desktop, mobile and server-based operating systems. Ruby is also supported across a number of cloud hosting platforms like Jelastic, Heroku, Google Cloud Platform and others. Tools such as RVM and RBEnv, facilitate installation and partitioning of multiple ruby versions, and multiple 'gemsets' on one machine. Repositories and libraries RubyGems is Ruby's package manager. A Ruby package is called a "gem" and can be installed via the command line. Most gems are libraries, though a few exist that are applications, such as IDEs. There are over 100,000 Ruby gems hosted on RubyGems.org. Many new and existing Ruby libraries are hosted on GitHub, a service that offers version control repository hosting for Git. The Ruby Application Archive, which hosted applications, documentation, and libraries for Ruby programming, was maintained until 2013, when its function was transferred to RubyGems. See also Comparison of programming languages Metasploit Project Why's (poignant) Guide to Ruby Crystal (programming language) Ruby on Rails References Further reading External links Ruby documentation Articles with example Ruby code Class-based programming languages Dynamic programming languages Dynamically typed programming languages Free software programmed in C ISO standards Japanese inventions Multi-paradigm programming languages Object-oriented programming languages Programming languages created in 1995 Programming languages with an ISO standard Scripting