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Ruby (programming language)
[ temporary import ]
please note:
- the content below is remote from Wikipedia
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{{about|the programming language||Ruby (disambiguation)}}{{distinguish|Ruby on Rails}}









! Ruby !! Semantic versioning| PATCH: number of commits since last MINOR release (will be reset at 0 when releasing MINOR).
|| -
factoids
title Ruby
| logo = (File:Ruby logo.svg|frameless|100px)
| paradigm = Multi-paradigm: functional, imperative, object-oriented, reflective
| designer = Yukihiro Matsumoto
| developer = Yukihiro Matsumoto, et al.
| typing = Duck, dynamic, strong
| scope = Lexical, sometimes dynamic
| implementations = Ruby MRI, YARV, Rubinius, MagLev, JRuby, MacRuby, RubyMotion, Mruby









url weblink
|title = Ioke
|last = Bini
|first = Ola
|work = Ioke.org
|accessdate = 2011-07-21
|quote = inspired by Io, Smalltalk, Lisp and Ruby
|deadurl = yes
|archiveurl =weblink" title="web.archive.org/web/20110721091046weblink">weblink
|archivedate = 2011-07-21
|df =
Julia,WEB,weblink Julia 1.0 Documentation: Introduction, 6 October 2018, Mirah, Nu,
WEB
,weblink
, About Nuâ„¢
, Burks
, Tim
, Programming Nuâ„¢
, Neon Design Technology, Inc.
, 2011-07-21,
Reia, Ring,WEB,weblink Ring and other languages, Ring Team, 3 December 2017, ring-lang.net, ring-lang, SwiftWEB,weblink Chris Lattner's Homepage, Lattner, Chris, 2014-06-03, 2014-06-03, Chris Lattner, The Swift language is the product of tireless effort from a team of language experts, documentation gurus, compiler optimization ninjas, and an incredibly important internal dogfooding group who provided feedback to help refine and battle-test ideas. Of course, it also greatly benefited from the experiences hard-won by many other languages in the field, drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list.,
| license = Ruby License, GPLv2, or 2-clause BSD licenseWEB,weblink [ruby] Contents of /trunk/COPYING, 2 May 2015, WEB,weblink [ruby] Contents of /trunk/GPL, 2 May 2015, WEB,weblink [ruby] Contents of /trunk/BSDL, 2 May 2015,
| website = {{urlweblink}}
| wikibooks = Ruby Programming
| slogan = A programmer's best friend
| year = | programming_language = C
| influenced_by = Ada, C++, CLU, Dylan, Eiffel,
BOOK
, Cooper
, Peter
, Beginning Ruby: From Novice to Professional
, 2nd
, Beginning from Novice to Professional
, 2009
, APress
, Berkeley
, 1-4302-2363-4
, 101
, To a lesser extent, Python, LISP, Eiffel, Ada, and C++ have also influenced Ruby.,
Lisp, Lua, Perl, Python, Smalltalk
BOOK
, Bini
, Ola
, Practical JRuby on Rails Web 2.0 Projects: Bringing Ruby on Rails to Java
, 2007
, APress
, Berkeley
, 1-59059-881-4
, 3
, It draws primarily on features from Perl, Smalltalk, Python, Lisp, Dylan, and CLU.,


| operating_system = Cross-platform
| file_ext = .rb
}}
Ruby is an interpreted, high-level, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.Ruby is dynamically typed and garbage-collected. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp.WEB,weblink About Ruby, 2 March 2014,

History

Early concept

Matsumoto has said that Ruby was conceived in 1993. In a 1999 post to the ruby-talk mailing list, he describes some of his early ideas about the language:WEB,weblink The Ruby Language FAQ, Shugo Maeda, 17 December 2002, 2 March 2014,
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 describes the design of Ruby as being like 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.{{citation|url=http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/179642|title=ruby-talk: Re: Ruby's lisp features|author=Yukihiro Matsumoto|date=13 February 2006|accessdate=2 March 2014}}

The name "Ruby"

The name "Ruby" originated during an online chat session between Matsumoto and Keiju Ishitsuka on February 24, 1993, before any code had been written for the language.WEB,weblink History of Ruby, Initially two names were proposed: "Coral" and "Ruby". Matsumoto chose the latter in a later e-mail to Ishitsuka.WEB,weblink [FYI: historic] The decisive moment of the language name Ruby. (Re: [ANN] ruby 1.8.1), E-mail from Hiroshi Sugihara to ruby-talk, Matsumoto later noted a factor in choosing the name "Ruby" â€“ it was the birthstone of one of his colleagues.WEB
,weblink
, The Ruby Language FAQ – 1.3 Why the name 'Ruby'?
, Ruby-Doc.org
, April 10, 2012,
MAILING LIST
,weblink
, Re: the name of Ruby?
, Ruby-Talk
, June 11, 1999
, Yukihiro Matsumoto
, April 10, 2012,

First publication

The first public release of Ruby 0.95 was announced on Japanese domestic newsgroups on December 21, 1995.WEB,weblink More archeolinguistics: unearthing proto-Ruby, 2 May 2015, yes,weblink" title="web.archive.org/web/20151106023204weblink">weblink 6 November 2015, WEB,weblink [ruby-talk:00382] Re: history of ruby, 2 May 2015, 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.WEB,weblink [ruby-list:124] TUTORIAL - ruby's features, 2 May 2015,

Early releases

Following the release of Ruby 0.95 in 1995, several stable versions of Ruby were released in the following years:
  • Ruby 1.0: December 25, 1996
  • Ruby 1.2: December 1998
  • Ruby 1.4: August 1999
  • Ruby 1.6: September 2000
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.WEB,weblink An Interview with the Creator of Ruby, 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.WEB,weblink Programming Ruby: Forward, Yukihiro Matsumoto, October 2000, 5 March 2014, 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

Ruby 1.8 was initially released August 2003, was stable for a long time, and was retired 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 2011WEB,weblink IPA 独立行政法人 情報処理推進機構:プレス発表 プログラム言語RubyのJIS規格(JIS X 3017)制定について, 2 May 2015, and an international standard (ISO/IEC 30170) in 2012.WEB,weblink IPA 独立行政法人 情報処理推進機構:プレス発表 プログラム言語Ruby、国際規格として承認, 2 May 2015, WEB,weblink ISO/IEC 30170:2012, 2017-03-10, 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.Web Development: Ruby on Rails. Devarticles.com (2007-03-22). Retrieved on 2013-07-17.

Ruby 1.9

Ruby 1.9 was released on Christmas Day in 2007. Effective with Ruby 1.9.3, released October 31, 2011,WEB
, Ruby 1.9.3 p0 is released
,weblink
, ruby-lang.org
, October 31, 2011
, February 20, 2013,
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.
WEB
, v1_9_3_0/NEWS
,weblink
, Ruby Apache Subversion, Subversion source repository
, ruby-lang.org
, September 17, 2011
, February 20, 2013,
Adoption of 1.9 was slowed by changes from 1.8 that required many popular third party gems to be rewritten.
Ruby 1.9 introduces many significant changes over the 1.8 series.Ruby 1.9: What to Expect. Slideshow.rubyforge.org. Retrieved on 2013-07-17. Examples:
  • block local variables (variables that are local to the block in which they are declared)
  • an additional lambda syntax: {{code|2=ruby|1=f = ->(a,b) {{(}} puts a + b {{)}}}}
  • an additional Hash literal syntax using colons for symbol keys: {{code|2=ruby|1={{(}}symbol_key: "value"{{)}} == {{(}}:symbol_key => "value"{{)}}}}
  • per-string character encodings are supported
  • new socket API (IPv6 support)
  • require_relative import security
Ruby 1.9 has been obsolete since February 23, 2015,WEB,weblink Support for Ruby 1.9.3 has ended, 2 May 2015, and it will no longer receive bug and security fixes. Users are advised to upgrade to a more recent version.

Ruby 2.0

Ruby 2.0 added several new features, including:
  • method keyword arguments,
  • a new method, Moduleprepend, for extending a class,
  • a new literal for creating an array of symbols,
  • new API for the lazy evaluation of Enumerables, and
  • a new convention of using to_h to convert objects to Hashes.Endoh, Yusuke. (2013-02-24) Ruby 2.0.0-p0 is released. Ruby-lang.org. Retrieved on 2013-07-17.
Ruby 2.0 is intended to be fully backward compatible with Ruby 1.9.3. As of the official 2.0.0 release on February 24, 2013, there were only five known (minor) incompatibilities.Endoh, Yusuke. (2013-02-24) Ruby 2.0.0-p0 is released. Ruby-lang.org. Retrieved on 2013-07-17.It has been obsolete since February 22, 2016,WEB,weblink Support plans for Ruby 2.0.0 and Ruby 2.1, usa, Ruby-lang.org, 2016-02-24, 2017-04-18, and it will no longer receive bug and security fixes. Users are advised to upgrade to a more recent version.

Ruby 2.1

Ruby 2.1.0 was released on Christmas Day in 2013.WEB,weblink Ruby 2.1.0 is released, December 25, 2013, December 26, 2013, The release includes speed-ups, bugfixes, and library updates.Starting with 2.1.0, Ruby's versioning policy is more like semantic versioning.WEB,weblink Semantic Versioning starting with Ruby 2.1.0, December 21, 2013, December 27, 2013, Although similar, Ruby's versioning policy is not compatible with semantic versioning:{| class="wikitable"
MAJOR: Increased when incompatible change which can’t be released in MINOR. Reserved for special events. >| MAJOR: Increased when you make incompatible API changes.
MINOR: increased every Christmas, may be API incompatible. >| MINOR: increased when you add functionality in a backwards-compatible manner.
TEENY: security or bug fix which maintains API compatibility. May be increased more than 10 (such as 2.1.11), and will be released every 2–3 months. >| PATCH: increased when you make backwards-compatible bug fixes.
Semantic versioning also provides additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format, not available at Ruby.Ruby 2.1 has been obsolete since April 1, 2017,WEB,weblink Support for Ruby 2.1 has ended, 4 April 2017, and it will no longer receive bug and security fixes. Users are advised to upgrade to a more recent version.

Ruby 2.2

Ruby 2.2.0 was released on Christmas Day in 2014.WEB,weblink Ruby 2.2.0 Released, December 25, 2014, January 4, 2015, The release includes speed-ups, bugfixes, and library updates and removes some deprecated APIs. Most notably, Ruby 2.2.0 introduces changes to memory handling{{snd}} 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.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.WEB,weblink ruby/NEWS at v2_2_0 · ruby/ruby · GitHub, GitHub, 2 May 2015,
PowerPC64 performance: Since version 2.2.1,WEB,weblink Ruby 2.2.1 Released, 12 July 2016, Gustavo Frederico Temple Pedrosa, Vitor de Lima, Leonardo Bianconi, 2015, Ruby MRI performance on PowerPC64 was improved.WEB,weblink v2.2.1 ChangeLog, 12 July 2016, Gustavo Frederico Temple Pedrosa, Vitor de Lima, Leonardo Bianconi, 2015, WEB,weblink Specifying non volatile registers for increase performance in ppc64, 12 July 2016, Gustavo Frederico Temple Pedrosa, Vitor de Lima, Leonardo Bianconi, 2014, WEB,weblink Specifying MACRO for increase performance in ppc64, 12 July 2016, Gustavo Frederico Temple Pedrosa, Vitor de Lima, Leonardo Bianconi, 2014,

Ruby 2.3

Ruby 2.3.0 was released on Christmas Day in 2015. A few notable changes include:
  • The ability to mark all string literals as frozen by default with a consequently large performance increase in string operations.WEB,weblink Ruby 2.3.0 changes and features - Running with Ruby, dev.mensfeld.pl,
  • Hash comparison to allow direct checking of key/value pairs instead of just keys.
  • A new safe navigation operator &. that can ease nil handling (e.g. instead of {{code|lang=ruby|code=if obj && obj.foo && obj.foo.bar}}, we can use if obj&.foo&.bar).
  • The did_you_mean gem is now bundled by default and required on startup to automatically suggest similar name matches on a NameError or NoMethodError.
  • Hashdig and Arraydig to easily extract deeply nested values (e.g. given {{code|lang=ruby|code=profile = { social: { wikipedia: { name: 'Foo Baz' } } }}}, the value Foo Baz can now be retrieved by profile.dig(:social, :wikipedia, :name)).
  • .grep_v(regexp) which will match all negative examples of a given regular expression in addition to other new features.
The 2.3 branch also 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.WEB,weblink Ruby/NEWS at v.2_3_0 - ruby/ruby - Github, GitHub, 25 December 2015,

Ruby 2.4

Ruby 2.4.0 was released on Christmas Day in 2016. A few notable changes include:
  • Bindingirb: Start a REPL session similar to binding.pry
  • Unify Fixnum and Bignum into Integer class
  • String supports Unicode case mappings, not just ASCII
  • A new method, Regexpmatch?, which is a faster boolean version of Regexpmatch
  • Thread deadlock detection now shows threads with their backtrace and dependency
The 2.4 branch also includes performance improvements to hash table, Array#max, Array#min, and instance variable access.WEB,weblink Ruby 2.4.0 Released, www.ruby-lang.org, 2016-12-30,

Ruby 2.5

Ruby 2.5.0 was released on Christmas Day in 2017.WEB,weblink Ruby 2.5.0 Released, 2018-05-02, A few notable changes include:
  • rescue and ensure statements automatically use a surrounding do-end block (less need for extra begin-end blocks)
  • Method-chaining with yield_self
  • Support branch coverage and method coverage measurement
  • Easier Hash transformations with Hashslice and Hashtransform_keys
On top of that come a lot of performance improvements like faster block passing (3 times faster), faster Mutexes, faster ERB templates and improvements on some concatenation methods.

Ruby 2.6

Ruby 2.6.0 was released on Christmas Day in 2018.WEB
,weblink
, Ruby 2.6.0 Released
, Ruby Programming Language
, 2018-12-25
, 2018-12-25, A few notable changes include:
  • JIT (experimental)
  • RubyVM::AbstractSyntaxTree (experimental)
">

Table of versions {| class"wikitable"

! Version! Latest teeny version! Initial release date! End of support phase! End of security maintenance phaseo |1.0}}| NAWEBSITE=WWW.RUBYINSIDE.COM, | NA| NAo |1.8}}PUBLISHER=, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, o |1.9}}WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, o |2.0}}WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, | 2015-02-24| 2016-02-24o |2.1}}WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, HTTPS://WWW.RUBY-LANG.ORG/EN/NEWS/2016/03/30/RUBY-2-1-9-RELEASED/>TITLE=RUBY 2.1.9 RELEASED, www.ruby-lang.org, WEBSITE=BUGS.RUBY-LANG.ORG, HTTPS://WWW.RUBY-LANG.ORG/EN/NEWS/2017/04/01/SUPPORT-OF-RUBY-2-1-HAS-ENDED/>TITLE=SUPPORT OF RUBY 2.1 HAS ENDED, www.ruby-lang.org, o |2.2}}WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, | 2018-03-31o |2.3}}WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, | 2019-03-31co |2.4}}LAST=DATE=ACCESS-DATE=, WEBSITE=WWW.RUBY-LANG.ORG, WEBSITE=WWW.RUBY-LANG.ORG, | 2020-04-01co |2.5}}| 2.5.5WEB
,weblink
, Ruby 2.5.5 Released
, Ruby Programming Language
, 2019-03-15
, 2019-03-25,
WEBSITE=WWW.RUBY-LANG.ORG, | {{TBA}}| {{TBA}}c |2.6}}| 2.6.3WEBSITE=WWW.RUBY-LANG.ORG, | {{TBA}}| {{TBA}}p |3.0}}|PUBLISHER=, HTTP://WWW.MANGROVE.COM/EN/JOURNAL/2015-11-17-WHATS-COMING-IN-RUBY-3-AND-RAILS-5/>TITLE=WHAT’S COMING IN RUBY 3 AND RAILS 5 - MANGROVE, www.mangrove.com, | {{TBA}}| {{TBA}} {{Versionshow=111101}}

Philosophy

File:Yukihiro Matsumoto.JPG|thumb|Yukihiro MatsumotoYukihiro MatsumotoMatsumoto has said that Ruby is designed for programmer productivity and fun, following the principles of good user interface design.WEB,weblink The Ruby Programming Language, 2 May 2015, At a Google Tech Talk in 2008 Matsumoto further stated, "I hope to see Ruby help every programmer in the world to be productive, and to enjoy programming, and to be happy. That is the primary purpose of Ruby language."{{YouTube|oEkJvvGEtB4|Google Tech Talks – Ruby 1.9}} He stresses that systems design needs to emphasize human, rather than computer, needs:WEB,weblink The Philosophy of Ruby, Bill Venners, 2 May 2015, Ruby is said to follow the principle of least astonishment (POLA), meaning that the language should behave in such a way as to minimize confusion for experienced users. Matsumoto has said his primary design goal was to make a language that he himself enjoyed using, by minimizing programmer work and possible confusion. He has said that he had not applied the principle of least astonishment to the design of Ruby, but nevertheless the phrase has come to be closely associated with the Ruby programming language. The phrase has itself been a source of surprise, as novice users may take it to mean that Ruby's behaviors try to closely match behaviors familiar from other languages. In a May 2005 discussion on the newsgroup comp.lang.ruby, Matsumoto attempted to distance Ruby from POLA, explaining that because any design choice will be surprising to someone, he uses a personal standard in evaluating surprise. If that personal standard remains consistent, there would be few surprises for those familiar with the standard.WEB,weblink Welcome to RUBYWEEKLYNEWS.ORG, 4 July 2017, bot: unknown,weblink" title="web.archive.org/web/20170704073422weblink">weblink 4 July 2017, Matsumoto defined it this way in an interview:

Features

Semantics

Ruby is object-oriented: every value is an object, including classes and instances of types that many other languages designate as primitives (such as integers, booleans, and "null"). Variables always hold references to objects. Every function is a method and methods are always called on an object. Methods defined at the top level scope become methods of the Object class. Since this class is an ancestor of every other class, such methods can be called on any object. They are also visible in all scopes, effectively serving as "global" procedures. Ruby supports inheritance with dynamic dispatch, mixins and singleton methods (belonging to, and defined for, a single instance rather than being defined on the class). Though Ruby does not support multiple inheritance, classes can import modules as mixins.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-basedGreen threads threads. Ruby features dynamic typing, and supports parametric polymorphism.According to the Ruby FAQ, the syntax is similar to Perl and the semantics are similar to Smalltalk, but it differs greatly from Python.WEB,weblink The Ruby Language FAQ: How Does Ruby Stack Up Against...?, 2 May 2015,

Syntax

The syntax of Ruby is broadly similar to that of Perl and Python. Class and method definitions are signaled by keywords, whereas code blocks can be both defined by keywords or braces. In contrast to Perl, variables are not obligatorily prefixed with a sigil. When used, the sigil changes the semantics of scope of the variable. For practical purposes there is no distinction between expressions and statements.WEB, [ruby-talk:01120] Re: The value of while..., In Ruby's syntax, statement is just a special case of an expression that cannot appear as an argument (e.g. multiple assignment).,weblink WEB, [ruby-talk:02460] Re: Precedence question, statement [...] can not be part of expression unless grouped within parentheses.,weblink Line breaks are significant and taken as the end of a statement; a semicolon may be equivalently used. Unlike Python, indentation is not significant.One of the differences from Python and Perl is that Ruby keeps all of its instance variables completely private to the class and only exposes them through accessor methods (attr_writer, attr_reader, etc.). Unlike the "getter" and "setter" methods of other languages like C++ or Java, accessor methods in Ruby can be created with a single line of code via metaprogramming; however, accessor methods can also be created in the traditional fashion of C++ and Java. As invocation of these methods does not require the use of parentheses, it is trivial to change an instance variable into a full function, without modifying a single line of calling code or having to do any refactoring achieving similar functionality to C# and VB.NET property members.Python's property descriptors are similar, but come with a tradeoff in the development process. If one begins in Python by using a publicly exposed instance variable, and later changes the implementation to use a private instance variable exposed through a property descriptor, code internal to the class may need to be adjusted to use the private variable rather than the public property. Ruby’s design forces all instance variables to be private, but also provides a simple way to declare set and get methods. This is in keeping with the idea that in Ruby, one never directly accesses the internal members of a class from outside the class; rather, one passes a message to the class and receives a response.See the Examples section below for samples of code demonstrating Ruby syntax.

Interaction

{{See also|Interactive Ruby Shell}}The Ruby official distribution also includes irb, an interactive command-line interpreter that can be used to test code quickly. The following code fragment represents a sample session using irb:$ irbirb(main):001:0> puts 'Hello, World'Hello, World
=> nil
irb(main):002:0> 1+2
=> 3

Examples

{{unreferenced section|date=January 2014}}The following examples can be run in a Ruby shell such as Interactive Ruby Shell, or saved in a file and run from the command line by typing ruby .Classic Hello world example:puts 'Hello World!'Some basic Ruby code:
  1. Everything, including a literal, is an object, so this works:
-199.abs # => 199'ice is nice'.length # => 11'ruby is cool.'.index('u') # => 1"Nice Day Isn't It?".downcase.split('').uniq.sort.join
  1. => " '?acdeinsty"
Input:print 'Please type name >'name = gets.chompputs "Hello #{name}."Conversions:puts 'Give me a number'number = gets.chompputs number.to_ioutput_number = number.to_i + 1puts output_number.to_s + ' is a bigger number.'

Strings

There are a variety of ways to define strings in Ruby.The following assignments are equivalent:a = "nThis is a double-quoted stringn"a = %Q{nThis is a double-quoted stringn}a = %{nThis is a double-quoted stringn}a = %/nThis is a double-quoted stringn/a = 3.14a.[](2) # => 3.14a.reverse # => 4, 5], 2, 1, 3.14, 'hi', 1]a.flatten.uniq # => [1, 'hi', 3.14, 2, 4, 5]Constructing and using an associative array (in Ruby, called a hash):hash = Hash.new # equivalent to hash = {}hash = { :water => 'wet', :fire => 'hot' } # makes the previous line redundant as we are now
# assigning hash to a new, separate hash object
puts hash[:fire] # prints "hot"hash.each_pair do |key, value| # or: hash.each do |key, value|
puts "#{key} is #{value}"
end
  1. returns {:water=>"wet", :fire=>"hot"} and prints:
  2. water is wet
  3. fire is hot
hash.delete :water # deletes the pair :water => 'wet' and returns "wet"hash.delete_if {|key,value| value == 'hot'} # deletes the pair :fire => 'hot' and returns {}

Control structures

If statement:
  1. Generate a random number and print whether it's even or odd.
if rand(100).even?
puts "It's even"
else
puts "It's odd"
end

Blocks and iterators

The two syntaxes for creating a code block:{ puts 'Hello, World!' } # note the braces
  1. or:
do
puts 'Hello, World!'
endA code block can be passed to a method as an optional block argument. Many built-in methods have such arguments:File.open('file.txt', 'w') do |file| # 'w' denotes "write mode"
file.puts 'Wrote some text.'
end # file is automatically closed hereFile.readlines('file.txt').each do |line|
puts line
end
  1. => Wrote some text.
Parameter-passing a block to be a closure:
  1. In an object instance variable (denoted with '@'), remember a block.
def remember(&a_block)
@block = a_block
end
  1. Invoke the preceding method, giving it a block that takes a name.
remember {|name| puts "Hello, #{name}!"}
  1. Call the closure (note that this happens not to close over any free variables):
@block.call('Jon') # => "Hello, Jon!"Creating an anonymous function:proc {|arg| puts arg}Proc.new {|arg| puts arg}lambda {|arg| puts arg}->(arg) {puts arg} # introduced in Ruby 1.9Returning closures from a method:def create_set_and_get(initial_value=0) # note the default value of 0
closure_value = initial_value
[ Proc.new {|x| closure_value = x}, Proc.new { closure_value } ]
endsetter, getter = create_set_and_get # returns two valuessetter.call(21)getter.call # => 21
  1. Parameter variables can also be used as a binding for the closure,
  2. so the preceding can be rewritten as:
def create_set_and_get(closure_value=0)
[ proc {|x| closure_value = x } , proc { closure_value } ]
endYielding the flow of program control to a block that was provided at calling time:def use_hello
yield "hello"
end
  1. Invoke the preceding method, passing it a block.
use_hello {|string| puts string} # => 'hello'Iterating over enumerations and arrays using blocks:array = [1, 'hi', 3.14]array.each {|item| puts item }
  1. prints:
  2. 1
  3. 'hi'
  4. 3.14
array.each_index {|index| puts "#{index}: #{array[index]}" }
  1. prints:
  2. 0: 1
  3. 1: 'hi'
  4. 2: 3.14
  1. The following uses a (a..b) Range
(3..6).each {|num| puts num }
  1. prints:
  2. 3
  3. 4
  4. 5
  5. 6
  1. The following uses a (a...b) Range
(3...6).each {|num| puts num }
  1. prints:
  2. 3
  3. 4
  4. 5
A method such as inject can accept both a parameter and a block. The inject method iterates over each member of a list, performing some function on it while retaining an aggregate. This is analogous to the foldl function in functional programming languages. For example:[1,3,5].inject(10) {|sum, element| sum + element} # => 19On the first pass, the block receives 10 (the argument to inject) as sum, and 1 (the first element of the array) as element. This returns 11, which then becomes sum on the next pass. It is added to 3 to get 14, which is then added to 5 on the third pass, to finally return 19.Using an enumeration and a block to square the numbers 1 to 10 (using a range):(1..10).collect {|x| x*x} # => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]Or invoke a method on each item (map is a synonym for collect):(1..5).map(&:to_f) # => [1.0, 2.0, 3.0, 4.0, 5.0]

Classes

The following code defines a class named Person. In addition to initialize, the usual constructor to create new objects, it has two methods: one to override the comparison operator (so Array#sort can sort by age) and the other to override the to_s method (so Kernel#puts can format its output). Here, attr_reader is an example of metaprogramming in Ruby: attr_accessor defines getter and setter methods of instance variables, but attr_reader only getter methods. The last evaluated statement in a method is its return value, allowing the omission of an explicit return statement.class Person
attr_reader :name, :age
def initialize(name, age)
@name, @age = name, age
end
def (person) # the comparison operator for sorting
@age person.age
end
def to_s
"#{@name} (#{@age})"
end
endgroup = [
Person.new("Bob", 33),
Person.new("Chris", 16),
Person.new("Ash", 23)
]puts group.sort.reverseThe preceding code prints three names in reverse age order:Bob (33)Ash (23)Chris (16)Person is a constant and is a reference to a Class object.

Open classes

In Ruby, classes are never closed: methods can always be added to an existing class. This applies to all classes, including the standard, built-in classes. All that is needed to do is open up a class definition for an existing class, and the new contents specified will be added to the existing contents. A simple example of adding a new method to the standard library's Time class:
  1. re-open Ruby's Time class
class Time
def yesterday
self - 86400
end
endtoday = Time.now # => 2013-09-03 16:09:37 +0300yesterday = today.yesterday # => 2013-09-02 16:09:37 +0300Adding methods to previously defined classes is often called monkey-patching. If performed recklessly, the practice can lead to both behavior collisions with subsequent unexpected results and code scalability problems.Since Ruby 2.0 it has been possible to use refinements to reduce the potentially negative consequences of monkey-patching, by limiting the scope of the patch to particular areas of the code base.
  1. re-open Ruby's Time class
module RelativeTimeExtensions
refine Time do
def half_a_day_ago
self - 43200
end
end
endmodule MyModule
class MyClass
# Allow the refinement to be used
using RelativeTimeExtensions


def window
Time.now.half_a_day_ago
end
end
end

Exceptions

An exception is raised with a raise call:raiseAn optional message can be added to the exception:raise "This is a message"Exceptions can also be specified by the programmer:raise ArgumentError, "Illegal arguments!"Alternatively, an exception instance can be passed to the raise method:raise ArgumentError.new("Illegal arguments!")This last construct is useful when raising an instance of a custom exception class featuring a constructor that takes more than one argument:class ParseError < Exception
def initialize(input, line, pos)
super "Could not parse '#{input}' at line #{line}, position #{pos}"
end
endraise ParseError.new("Foo", 3, 9)Exceptions are handled by the rescue clause. Such a clause can catch exceptions that inherit from StandardError. Other flow control keywords that can be used when handling exceptions are else and ensure:begin
# do something
rescue
# handle exception
else
# do this if no exception was raised
ensure
# do this whether or not an exception was raised
endIt is a common mistake to attempt to catch all exceptions with a simple rescue clause. To catch all exceptions one must write:begin
# do something
rescue Exception
# Exception handling code here.
# Don't write only "rescue"; that only catches StandardError, a subclass of Exception.
endOr catch particular exceptions:begin
# do something
rescue RuntimeError
# handle only RuntimeError and its subclasses
endIt is also possible to specify that the exception object be made available to the handler clause:begin
# do something
rescue RuntimeError => e
# handling, possibly involving e, such as "puts e.to_s"
endAlternatively, the most recent exception is stored in the magic global $!.Several exceptions can also be caught:begin
# do something
rescue RuntimeError, Timeout::Error => e
# handling, possibly involving e
end

Metaprogramming

{{refimprove section|date=January 2014}}Ruby code can programmatically modify, at runtime, aspects of its own structure that would be fixed in more rigid languages, such as class and method definitions. This sort of metaprogramming can be used to write more concise code and effectively extend the language.For example, the following Ruby code generates new methods for the built-in String class, based on a list of colors. The methods wrap the contents of the string with an HTML tag styled with the respective color.COLORS = { black: "000",
red: "f00",
green: "0f0",
yellow: "ff0",
blue: "00f",
magenta: "f0f",
cyan: "0ff",
white: "fff" }
class String
COLORS.each do |color,code|
define_method "in_#{color}" do
"#{self}"
end
end
endThe generated methods could then be used like this:"Hello, World!".in_blue
=> "Hello, World!"
To implement the equivalent in many other languages, the programmer would have to write each method (in_black, in_red, in_green, etc.) separately.Some other possible uses for Ruby metaprogramming include:
  • intercepting and modifying method calls
  • implementing new inheritance models
  • dynamically generating classes from parameters
  • automatic object serialization
  • interactive help and debugging

Implementations

{{See also|Ruby MRI#Operating systems}}

Matz's Ruby interpreter

The original Ruby interpreter is often referred to as Matz's Ruby Interpreter or MRI. This implementation is written in C and uses its own Ruby-specific virtual machine.The standardized and retired Ruby 1.8 implementation was written in C, as a single-pass interpreted language.WEB,weblink We retire Ruby 1.8.7, 2 May 2015, Starting with Ruby 1.9, and continuing with Ruby 2.x and above, the official Ruby interpreter has been YARV ("Yet Another Ruby VM"), and this implementation has superseded the slower virtual machine used in previous releases of MRI.

Alternate implementations

{{As of|2018}}, there are a number of alternative implementations of Ruby, including JRuby, Rubinius, and mruby. Each takes a different approach, with JRuby and Rubinius providing just-in-time compilation and mruby also providing ahead-of-time compilation.Ruby has three major alternate implementations:
  • JRuby, a mixed Java and Ruby implementation that runs on the Java virtual machine. JRuby currently targets Ruby 2.5.
  • TruffleRuby, a Java implementation using the Truffle language implementation framework with GraalVM
  • Rubinius, a C++ bytecode virtual machine that uses LLVM to compile to machine code at runtime. The bytecode compiler and most core classes are written in pure Ruby. Rubinius currently targets Ruby 2.3.1.
Other Ruby implementations include:
  • MagLev, a Smalltalk implementation that runs on GemTalk Systems' GemStone/S VM
  • mruby, an implementation designed to be embedded into C code, in a similar vein to Lua. It is currently being developed by Yukihiro Matsumoto and others
  • RGSS, or Ruby Game Scripting System, a proprietary implementation that is used by the RPG Maker series of software for game design and modification of the RPG Maker engine
  • A transpiler (partial) from Ruby to Julia, julializer is available. It can be used for a large speedup over e.g. Ruby or JRuby implementations (may only be useful for numerical code).WEB,weblink GitHub - remove/virtual_module: Born to make your Ruby Code more than 3x faster. Hopefully.,
  • Topaz, a Ruby implementation written in Python
  • Opal, a web-based interpreter that compiles Ruby to JavaScript
Other now defunct Ruby implementations were: 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 RubiniusWEB
,weblink
, The Why, What, and How of Rubinius 1.0's Release
, Peter Cooper
, 2010-05-18,
are all able to run Rails unmodified in a production environment.

Platform support

Matsumoto originally did Ruby development on the 4.3BSD-based Sony NEWS-OS 3.x, but later migrated his work to SunOS 4.x, and finally to Linux.WEB,weblink IBM developerWorks â€“ Ruby: a new language, Maya Stodte, February 2000, 3 March 2014, yes,weblink" title="web.archive.org/web/20000818164241weblink">weblink August 18, 2000, WEB,weblink lang-ruby-general: Re: question about Ruby initial development, Yukihiro Matsumoto, August 2002, 3 March 2014, By 1999, Ruby was known to work across many different operating systems, including NEWS-OS, SunOS, AIX, SVR4, Solaris, NEC UP-UX, NeXTSTEP, BSD, Linux, Mac OS, DOS, Windows, and BeOS.WEB,weblink ruby-talk: Re: hah, check these errors, Yukihiro Matsumoto, 5 January 1999, 3 March 2014, Modern Ruby versions and implementations are available on many operating systems, such as Linux, BSD, Solaris, AIX, macOS, Windows, Windows Phone,WEB,weblink Iron Ruby on Windows Phone 7, Windows CE, Symbian OS, BeOS, and IBM i.

Repositories and libraries

RubyGems is Ruby's package manager. A Ruby package is called a "gem" and can easily be installed via the command line. Most gems are libraries, though a few exist that are applications, such as IDEs.WEB,weblink The Ruby Toolbox, 2015-04-04, There are over 10,000 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.WEB,weblink We retire raa.ruby-lang.org, 2013-08-08, 2016-01-03,

See also

{{Clear}}

References

{{Reflist|30em}}

Further reading

  • {{citation| first1 = Sandi| last1 = Metz| date = September 5, 2012| title = Practical Object-Oriented Design in Ruby| edition = First| publisher = Addison-Wesley| page = 272| isbn = 0-321-72133-0| url =weblink
}}
  • {hide}citation| first1 = Jeremy| last1 = McAnally| first2 = Assaf| last2 = Arkin| date = March 28, 2009| title = Ruby in Practice| edition = First| publisher = Manning Publications| page = 360| isbn = 1-933988-47-9| url =
{edih}
  • {{citation| first1 = Dave| last1 = Thomas| first2 = Chad| last2 = Fowler| first3 = Andy| last3 = Hunt| date = April 28, 2009| title = Programming Ruby 1.9: The Pragmatic Programmers' Guide| edition = Third| publisher = Pragmatic Bookshelf| page = 1000| isbn = 1-934356-08-5| url =weblink
}}
  • {hide}citation| first1 = David| last1 = Black| date = June 4, 2009| title = The Well-Grounded Rubyist| edition = First| publisher = Manning Publications| page = 520| isbn = 1-933988-65-7| url =
{edih}
  • {{citation| first1 = David| last1 = Flanagan| first2 = Yukihiro| last2 = Matsumoto| date = January 25, 2008| title = The Ruby Programming Language| edition = First| publisher = O'Reilly Media| page = 446| isbn = 0-596-51617-7| url =weblink
}}
  • {{citation| first1 = Kevin| last1 = Baird| date = June 8, 2007| title = Ruby by Example: Concepts and Code| edition = First| publisher = No Starch Press| page = 326| isbn = 1-59327-148-4| url =weblink
}}
  • {{citation| first1 = Michael| last1 = Fitzgerald| date = May 14, 2007| title = Learning Ruby| edition = First| publisher = O'Reilly Media| page = 255| isbn = 0-596-52986-4| url =weblink
}}
  • {{citation| first1 = Peter| last1 = Cooper| date = March 26, 2007| title = Beginning Ruby: From Novice to Professional| edition = First| publisher = Apress| page = 664| isbn = 1-59059-766-4| url =weblink
}}
  • {{citation| first1 = Hal| last1 = Fulton| date = November 4, 2006| title = The Ruby Way| edition = Second| publisher = Addison-Wesley| page = 888| isbn = 0-596-52369-6| url =weblink
}}
  • {{citation| first1 = Lucas| last1 = Carlson| first2 = Leonard| last2 = Richardson| date = July 19, 2006| title = Ruby Cookbook| edition = First| publisher = O'Reilly Media| page = 906| isbn = 0-596-52369-6| url =weblink
}}

External links

{{Commons category|Ruby programming language}}{{Wikiversity|Topic:Ruby}} {{Ruby programming language}}{{Programming languages}}{{FOSS}}{{ISO standards}}{{Authority control}}

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