Ruby is a general-purpose programming language designed with an emphasis on programming productivity and simplicity. In Ruby, everything is an object, including primitive data types. Development of the language began in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. Ruby is interpreted, high-level, and dynamically typed; its interpreter uses garbage collection and just-in-time compilation. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, BASIC, and Lisp.
History
Early concept According to Matsumoto, Ruby was conceived in 1993. In a 1999 post to the Ruby-Talk mailing list, he shared some of his early ideas about the language:
I was talking with my colleague about the possibility of an object-oriented scripting language. I knew Perl (Perl4, not Perl5), but I didn't like it really, because it had the smell of a toy language (it still has). The object-oriented language seemed very promising. I knew Python then. But I didn't like it, because I didn't think it was a true object-oriented language – OO features appeared to be add-on to the language. As a language maniac and OO fan for 15 years, I really wanted a genuine object-oriented, easy-to-use scripting language. I looked for but couldn't find one. So I decided to make it. Matsumoto described Ruby's design as resembling a simple Lisp language at its core, with an object system like that of Smalltalk, blocks inspired by higher-order functions, and practical utility like that of Perl. The name "Ruby" originated during an online chat session between Matsumoto and Keiju Ishitsuka on 24 February 1993, before any code had been written. Two names were initially proposed: "Coral" and "Ruby". Matsumoto chose the latter in a subsequent email to Ishitsuka. He also noted that one factor influencing the choice of the name was that a colleague's birthstone was ruby.
Early releases The first public release of Ruby 0.95 was announced on Japanese domestic newsgroups on 21 December 1995. Subsequently, three more versions of Ruby were released in two days. The release coincided with the launch of the Japanese-language ruby-list mailing list, which was the first mailing list for the new language. Already present at this stage of development were many of the features familiar in later releases of Ruby, including object-oriented design, classes with inheritance, mixins, iterators, closures, exception handling and garbage collection. After the release of Ruby 0.95 in 1995, several stable versions of Ruby were released in these years. In 1997, the first article about Ruby was published on the Web. In the same year, Matsumoto was hired by netlab.jp to work on Ruby as a full-time developer. In 1998, the Ruby Application Archive was launched by Matsumoto, along with a simple English-language homepage for Ruby. In 1999, the first English language mailing list ruby-talk began, which signaled a growing interest in the language outside Japan. In this same year, Matsumoto and Keiju Ishitsuka wrote the first book on Ruby, The Object-oriented Scripting Language Ruby (オブジェクト指向スクリプト言語 Ruby), which was published in Japan in October 1999. It would be followed in the early 2000s by around 20 books on Ruby published in Japanese. By 2000, Ruby was more popular than Python in Japan. In September 2000, the first English language book Programming Ruby was printed, which was later freely released to the public, further widening the adoption of Ruby amongst English speakers. In early 2002, the English-language ruby-talk mailing list was receiving more messages than the Japanese-language ruby-list, demonstrating Ruby's increasing popularity in the non-Japanese speaking world.
Ruby 1.8 and 1.9 Ruby 1.8 was initially released in August 2003, was stable for a long time, and was retired in June 2013. Although deprecated, there is still code based on it. Ruby 1.8 is only partially compatible with Ruby 1.9. Ruby 1.8 has been the subject of several industry standards. The language specifications for Ruby were developed by the Open Standards Promotion Center of the Information-Technology Promotion Agency (a Japanese government agency) for submission to the Japanese Industrial Standards Committee (JISC) and then to the International Organization for Standardization (ISO). It was accepted as a Japanese Industrial Standard (JIS X 3017) in 2011 and an international standard (ISO/IEC 30170) in 2012.
Around 2005, interest in the Ruby language surged in tandem with Ruby on Rails, a web framework written in Ruby. Rails is frequently credited with increasing awareness of Ruby. Effective with Ruby 1.9.3, released 31 October 2011, Ruby switched from being dual-licensed under the Ruby License and the GPL to being dual-licensed under the Ruby License and the two-clause BSD license. Adoption of 1.9 was slowed by changes from 1.8 that required many popular third party gems to be rewritten.
Ruby 2 Ruby 2.0 was intended to be fully backward compatible with Ruby 1.9.3. As of the official 2.0.0 release on 24 February 2013, there were only five known incompatibilities. Starting with 2.1.0, Ruby's versioning policy changed to be more similar to semantic versioning, although it differs slightly in that minor version increments may be API incompatible. Ruby 2.2.0 includes speed-ups, bugfixes, and library updates and removes some deprecated APIs. Most notably, Ruby 2.2.0 introduces changes to memory handling – an incremental garbage collector, support for garbage collection of symbols and the option to compile directly against jemalloc. It also contains experimental support for using vfork(2) with system() and spawn(), and added support for the Unicode 7.0 specification. Since version 2.2.1, Ruby MRI performance on PowerPC64 was improved. Features that were made obsolete or removed include callcc, the DL library, Digest::HMAC, lib/rational.rb, lib/complex.rb, GServer, Logger::Application as well as various C API functions. Ruby 2.3.0 includes many performance improvements, updates, and bugfixes including changes to Proc#call, Socket and IO use of exception keywords, Thread#name handling, default passive Net::FTP connections, and Rake being removed from stdlib. Other notable changes include:
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