Ruby programming language

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Ruby

Paradigm
multi-paradigm
Appeared in
1995
Designed by
Yukihiro Matsumoto
Developer
Yukihiro Matsumoto, et al.
Stable release
1.9.2-p180 (February 18, 2011; 5 days ago (2011-02-18))
Typing discipline
duck, dynamic, strong
Major implementations
Ruby MRI, YARV, JRuby, Rubinius, IronRuby, MacRuby, HotRuby
Influenced by
Smalltalk, Perl, Lisp, Scheme, Python, CLU, Eiffel, Ada, Dylan
Influenced
Groovy, Nu, Falcon, Ioke, Mirah
OS
Cross-platform
License
Ruby License or GNU General Public License v2[1][2]
Usual file extensions
.rb, .rbw
Website
www.ruby-lang.org
Ruby Programming at Wikibooks
Ruby is a dynamic, reflective, general purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto. It was influenced primarily by Perl, Smalltalk, Eiffel, and Lisp.
Ruby supports multiple programming paradigms, including functional, object oriented, imperative and reflective. It also has a dynamic type system and automatic memory management; it is therefore similar in varying respects to Python, Perl, Lisp, Dylan, Pike, and CLU.
The standard 1.8.7 implementation is written in C, as a single-pass interpreted language. There is currently no specification of the Ruby language, so the original implementation is considered to be the de facto reference. As of 2010[update], there are a number of complete or upcoming alternative implementations of the Ruby language, including YARV, JRuby, Rubinius, IronRuby, MacRuby, and HotRuby. Each takes a different approach, with IronRuby, JRuby and MacRuby providing just-in-time compilation and MacRuby also providing ahead-of-time compilation. The official 1.9 branch uses YARV, as will 2.0 (development), and will eventually supersede the slower Ruby MRI.
Contents[hide]
1 History
1.1 Etymology of the name "Ruby"
1.2 First publication
1.3 Ruby 1.0
1.4 Ruby on Rails
1.5 Ruby 1.9
2 Philosophy
3 Features
4 Semantics
5 Syntax
6 Deviations from behavior elsewhere
7 Interaction
8 Examples
8.1 Strings
8.2 Collections
8.3 Blocks and iterators
8.4 Classes
8.4.1 Open classes
8.5 Exceptions
8.6 Metaprogramming
8.7 More examples
9 Implementations
10 Repositories and libraries
11 See also
12 References
13 Bibliography
14 External links
[edit] History
Ruby was conceived on February 24, 1993 by Yukihiro Matsumoto who wished to create a new language that balanced functional programming with imperative programming.[3] Matsumoto has stated, "I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python. That's why I decided to design my own language".[4]
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."[5]
[edit] Etymology of the name "Ruby"
The name "Ruby" was decided on during an online chat session between Matsumoto and Keiju Ishitsuka on February 24, 1993, before any code had been written for the language.[6] Initially two names were proposed: "Coral" and "Ruby", with the latter being chosen by Matsumoto in a later email to Ishitsuka.[7] Matsumoto has later stated that a factor in choosing the name "Ruby" was because it was the birthstone of one of his colleagues.
[edit] First publication
The first public release of Ruby 0.95 was announced on Japanese domestic newsgroups on December 21, 1995.[8][9] Subsequently three more versions of Ruby were released in two days.[6] 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.[10]
[edit] Ruby 1.0
Ruby reached version 1.0 on December 25, 1996.[6]
Following the release of Ruby 1.3 in 1999 the first English language mailing list ruby-talk began,[4] which signalled a growing interest in the language outside of 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.
[edit] Ruby on Rails
Around 2005, interest in the Ruby language surged in tandem with Ruby on Rails, a popular web application framework written in Ruby. Rails is frequently credited with making Ruby "famous".[11]
[edit] Ruby 1.9
The latest stable version of the reference implementation is 1.9.2.
Ruby 1.9 introduces many significant changes over the 1.8 series. Some examples are:
Block local variables (variables that are local to the block in which they are declared)
An additional lambda syntax (fun = ->(a,b) { puts a + b })
Per-string character encodings are supported
New socket API (IPv6 support)
[edit] Philosophy
Matsumoto has said that Ruby is designed for programmer productivity and fun, following the principles of good user interface design.[12] He stresses that systems design needs to emphasize human, rather than computer, needs:[13]
“
Often people, especially computer engineers, focus on the machines. They think, "By doing this, the machine will run faster. By doing this, the machine will run more effectively. By doing this, the machine will something something something." They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines. We are the masters. They are the slaves.
”
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 which he himself enjoyed using, by minimizing programmer work and possible confusion. He has said that he had not applied the principle of least surprise to the design of Ruby,[13] 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 comp.lang.ruby newsgroup, 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 will be few surprises for those familiar with the standard.[14]
Matsumoto defined it this way in an interview:[13]
“
Everyone has an individual background. Someone may come from Python, someone else may come from Perl, and they may be surprised by different aspects of the language. Then they come up to me and say, 'I was surprised by this feature of the language, so Ruby violates the principle of least surprise.' Wait. Wait. The principle of least surprise is not for you only. The principle of least surprise means principle of least my surprise [sic]. And it means the principle of least surprise after you learn Ruby very well. For example, I was a C++ programmer before I started designing Ruby. I programmed in C++ exclusively for two or three years. And after two years of C++ programming, it still surprises me.
”
[edit] Features
Thoroughly object-oriented with inheritance, mixins and metaclasses [15]
Dynamic typing and Duck typing
Everything is an expression (even statements) and everything is executed imperatively (even declarations)
Succinct and flexible syntax [16] that minimizes syntactic noise and serves as a foundation for domain-specific languages [17]
Dynamic reflection and alteration of objects to facilitate metaprogramming[18]
Lexical closures, Iterators and generators, with a unique block syntax [19]
Literal notation for arrays, hashes, regular expressions and symbols
Embedding code in strings (interpolation)
Default arguments
Four levels of variable scope (global, class, instance, and local) denoted by sigils and capitalization
Automatic garbage collection
First-class continuations
Strict boolean coercion rules (everything is true except false and nil)
Exception handling
Operator overloading
Built-in support for rational numbers, complex numbers and arbitrary-precision arithmetic
Custom dispatch behavior (through method_missing and const_missing)
Native threads and cooperative fibers
Initial support for Unicode and multiple character encodings (still buggy as of version 1.9)[20]
Native plug-in API in C
Interactive Ruby Shell (a REPL)
Centralized package management through RubyGems
Implemented on all major platforms
Large standard library
[edit] Semantics
Ruby is object-oriented: every data type is an object, including classes and types that many other languages designate as primitives (such as integers, booleans, and "nil"). 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 members 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-based[21] threads. Ruby features dynamic typing, and supports parametric polymorphism.
According to the Ruby FAQ,[22] "If you like Perl, you will like Ruby and be right at home with its syntax. If you like Smalltalk, you will like Ruby and be right at home with its semantics. If you like Python, you may or may not be put off by the huge difference in design philosophy between Python and Ruby/Perl."
[edit] Syntax
The syntax of Ruby is broadly similar to Perl and Python. Class and method definitions are signaled by keywords. In contrast to Perl, variables are not obligatorily prefixed with a sigil. When used, the sigil changes the semantics of scope of the variable. The most striking difference from C and Perl is that keywords are typically used to define logical code blocks, without braces (i.e., pair of { and }). For practical purposes there is no distinction between expressions and statements.[23] 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 of Ruby compared to 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 are created with a single line of code via metaprogramming. 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 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 removes this design decision by forcing 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 of it. Rather one passes a message to the class and receives a response.
See the examples section for samples of code demonstrating Ruby syntax.
[edit] Deviations from behavior elsewhere
Some features which differ notably from languages such as C or Perl:
The language syntax is sensitive to the capitalization of identifiers, in most cases treating capitalized variables as constants.
The sigils $ and @ do not indicate variable data type as in Perl, but rather function as scope resolution operators.
To denote a floating point without a decimal component, one must follow with a zero digit (99.0) or an explicit conversion (99.to_f). It is insufficient to append a dot (99.) since numbers are susceptible to method syntax.
Boolean evaluation of non-boolean data is strict: 0, "" and [] are all evaluated to true. In C, the expression 0 ? 1 : 0 evaluates to 0 (i.e. false). In Ruby, however, it yields 1, as all numbers evaluate to true; only nil and false evaluate to false. A corollary to this rule is that Ruby methods by convention — for example, regular-expression searches — return numbers, strings, lists, or other non-false values on success, but nil on failure. This convention is also used in Smalltalk, where only the special objects true and false can be used in a boolean expression.
Versions prior to 1.9 use plain integers to represent single characters, much like C. This may cause surprises when slicing strings: "abc"[0] yields 97 (the ASCII code of the first character in the string); to obtain "a" use "abc"[0,1] (a substring of length 1) or "abc"[0].chr.
The notation statement until expression, like Perl but unlike other languages' equivalent statements (e.g. do { statement } while (!(expression)); in C/C++/...), actually never runs the statement if the expression is already true. This is because statement until expression is actually syntactic sugar over until expression; statement; end, the equivalent of which in C/C++ is while (!(expression)) { statement; }, just as statement if expression is equivalent to if (expression) { statement; }. However, the notation begin statement end until expression in Ruby will in fact run the statement once even if the expression is already true, acting similar to the "do-while" of other languages. (Matz has expressed a desire to remove the special behavior of begin statement end until expression,[24] but it still exists as of ruby 1.9.)
Because constants are references to objects, changing what a constant refers to generates a warning, but modifying the object itself does not. For example, Greeting << " world!" if Greeting == "Hello" does not generate an error or warning. This is similar to final variables in Java or a const pointer to a non-const object in C++, but Ruby provides the functionality to "freeze" an object, unlike Java.
Some features which differ notably from other languages:
The usual operators for conditional expressions, and and or, do not follow the normal rules of precedence: and does not bind tighter than or. Ruby also has expression operators and && which work as expected.
A list of so-called gotchas may be found in Hal Fulton's book The Ruby Way, 2nd ed (ISBN 0-672-32884-4), Section 1.5. A similar list in the 1st edition pertained to an older version of Ruby (version 1.6), some problems of which have been fixed in the meantime. retry, for example, now works with while, until, and for, as well as iterators.
[edit] Interaction
See also: Interactive Ruby Shell
The Ruby official distribution also includes "irb", an interactive command-line interpreter which can be used to test code quickly. The following code fragment represents a sample session using irb:
$ irb
irb(main):001:0> puts "Hello, World"
Hello, World
=> nil
irb(main):002:0> 1+2
=> 3
[edit] Examples
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:
# Everything, including a literal, is an object, so this works:
-199.abs # 199
"ruby is cool".length # 12
"Your mother is nice.".index("u") # 2
"Nice Day Isn't It?".downcase.split("").uniq.sort.join # " '?acdeinsty"
Conversions:
puts "What's your favorite number?"
number = gets.chomp
output_number = number.to_i + 1
puts output_number.to_s + ' is a bigger and better favorite number.'
[edit] Strings
There are a variety of methods for defining strings in Ruby.
The following assignments are equivalent and support Variable interpolation:
a = "\nThis is a double-quoted string\n"
a = %Q{\nThis is a double-quoted string\n}
a = %{\nThis is a double-quoted string\n}
a = %/\nThis is a double-quoted string\n/
a = <<-BLOCK

This is a double-quoted string
BLOCK
The following assignments are equivalent and produce raw strings:
a = 'This is a single-quoted string'
a = %q{This is a single-quoted string}
[edit] Collections
Constructing and using an array:
a = [1, 'hi', 3.14, 1, 2, [4, 5]]

puts a[2] # 3.14
puts a.[](2) # 3.14
puts a.reverse # [[4, 5], 2, 1, 3.14, 'hi', 1]
puts a.flatten.uniq # [1, 'hi', 3.14, 2, 4, 5]
Constructing and using an associative array (called hashes in Ruby):
hash = { :water => 'wet', :fire => 'hot' }
puts hash[:fire] # Prints: hot

hash.each_pair do key, value # Or: hash.each do key, value
puts "#{key} is #{value}"
end

# Prints: water is wet
# fire is hot

hash.delete :water # Deletes :water => 'wet'
hash.delete_if {key,value value=='hot'} # Deletes :fire => 'hot'
[edit] Blocks and iterators
The two syntaxes for creating a code block:
{ puts "Hello, World!" } # Note the { braces }
#or
do
puts "Hello, World!"
end
When a code block is created it is always attached to a method as an optional block argument.
Parameter-passing a block to be a closure:
# In an object instance variable (denoted with '@'), remember a block.
def remember(&a_block)
@block = a_block
end

# Invoke the above method, giving it a block which takes a name.
remember {name puts "Hello, #{name}!"}

# When the time is right (for the object) -- call the closure!
@block.call("Jon")
# => "Hello, Jon!"
Creating an anonymous function:
proc {arg print arg}
Proc.new {arg print arg}
lambda {arg print arg}
Returning closures from a method:
def create_set_and_get(initial_value=0) # Note the default value of 0
closure_value = initial_value
return Proc.new {x closure_value = x}, Proc.new { closure_value }
end

setter, getter = create_set_and_get # ie. returns two values
setter.call(21)
getter.call # => 21

#You can also use a parameter variable as a binding for the closure.
#So the above can be rewritten as...

def create_set_and_get(closure_value=0)
proc {x closure_value = x } , proc { closure_value }
end
Yielding the flow of program control to a block which was provided at calling time:
def use_hello
yield "hello"
end

# Invoke the above 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
# => 'hi'
# => 3.14

array.each_index {index puts "#{index}: #{array[index]}" }
# => 0: 1
# => 1: 'hi'
# => 2: 3.14

# The following uses a Range
(3..6).each {num puts num }
# => 3
# => 4
# => 5
# => 6
A method such as inject() can accept both a parameter and a block. Inject 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} # => 19
On 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. 11 then becomes sum on the next pass, which is added to 3 to get 14. 14 is then added to 5, to finally return 19.
Blocks work with many built-in methods:
File.open('file.txt', 'w') do file # 'w' denotes "write mode".
file.puts 'Wrote some text.'
end # File is automatically closed here

File.readlines('file.txt').each do line
puts line
end
# => Wrote some text.
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]
[edit] 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, "attr_reader" only getter methods. Also, the last evaluated statement in a method is its return value, allowing the omission of an explicit 'return'.
class Person
attr_reader :name, :age
def initialize(name, age)
@name, @age = name, age
end
def <=>(person) # Comparison operator for sorting
@age <=> person.age
end
def to_s
"#@name (#@age)"
end
end

group = [
Person.new("Bob", 33),
Person.new("Chris", 16),
Person.new("Ash", 23)
]

puts group.sort.reverse
The above prints three names in reverse age order:
Bob (33)
Ash (23)
Chris (16)
[edit] Open classes
In Ruby, classes are never closed: you can always add methods to an existing class. This applies to the classes you write as well as the standard, built-in classes. All you have to do is open up a class definition for an existing class, and the new contents you specify will be added to whatever's there. A simple example of adding a new method to the standard library's Time class:
# re-open Ruby's Time class
class Time
def yesterday
self - 86400
end
end

today = Time.now # => Thu Aug 14 16:51:50 +1200 2008
yesterday = today.yesterday # => Wed Aug 13 16:51:50 +1200 2008
Adding methods to previously defined classes is often called monkey-patching. This practice, however, can lead to possible collisions of behavior and subsequent unexpected results, and is a concern for code scalability if performed recklessly.
[edit] Exceptions
An exception is raised with a raise call:
raise
An optional message can be added to the exception:
raise "This is a message"
You can also specify which type of exception you want to raise:
raise ArgumentError, "Illegal arguments!"
Alternatively, you can pass an exception instance to the raise method:
raise ArgumentError.new("Illegal arguments!")
This last construct is useful when you need to raise a custom exception class featuring a constructor which takes more than one argument:
class ParseError < Exception
def initialize input, line, pos
super "Could not parse '#{input}' at line #{line}, position #{pos}"
end
end

raise ParseError.new("Foo", 3, 9)
Exceptions are handled by the rescue clause. Such a clause can catch exceptions which inherit from StandardError. Also supported for use with 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
end
It 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
# don't write just rescue -- that only catches StandardError, a subclass of Exception
# Handle exception
end
Or catch particular exceptions:
begin
# ...
rescue RuntimeError
# handling
end
It is also possible to specify that the exception object be made available to the handler clause:
begin
# ...
rescue RuntimeError => e
# handling, possibly involving e, such as "print e.to_s"
end
Alternatively, the most recent exception is stored in the magic global $!.
You can also catch several exceptions:
begin
# ...
rescue RuntimeError, Timeout::Error => e
# handling, possibly involving e
end
[edit] Metaprogramming
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
end
The generated methods could then be used like so:
"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.) by hand.
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
[edit] More examples
More sample Ruby code is available as algorithms in the following articles:
Exponentiating by squaring
Trabb Pardo-Knuth algorithm
[edit] Implementations
See also: Ruby MRI#Operating systems
The newest version of Ruby, the recently released version 1.9, has a single working implementation written in C that utilizes a Ruby-specific virtual machine.
Ruby version 1.8 has two main implementations: The official Ruby interpreter often referred to as the Matz's Ruby Interpreter or MRI, which is the most widely used, and JRuby, a Java-based implementation that runs on the Java Virtual Machine.
There are other less-known or upcoming implementations such as Cardinal (an implementation for the Parrot virtual machine), IronRuby (alpha version available since July 24, 2008),[25] MacRuby, MagLev, Rubinius, Ruby.NET, XRuby and HotRuby (runs Ruby source code on a web browser and Flash).
The maturity of Ruby implementations tends to be measured by their ability to run the Ruby on Rails (Rails) framework, because it is a complex framework to implement, and it uses many Ruby-specific features. The point when a particular implementation achieves this goal is called The Rails singularity. As of May 2010, only the reference implementation (MRI) and JRuby are able to run Rails unmodified in a production environment. Rubinius recently released 1.0 and can run Rails,[26] but should not be used for production sites yet.[27] IronRuby[28][29] is starting to be able to run Rails test cases, but is still far from being production-ready.
Ruby is available on many operating systems such as Linux, Mac OS X, Microsoft Windows, Windows Phone 7,[30] Windows CE and most flavors of Unix.
Ruby 1.9 has recently been ported onto Symbian OS 9.x.[31]
[edit] Repositories and libraries
The Ruby Application Archive (RAA), as well as RubyForge, serve as repositories for a wide range of Ruby applications and libraries, containing more than seven thousand items. Although the number of applications available does not match the volume of material available in the Perl or Python community, there are a wide range of tools and utilities which serve to foster further development in the language.
RubyGems has become the standard package manager for Ruby libraries. It is very similar in purpose to Perl's CPAN, although its usage is more like apt-get.
Recently, many new and existing libraries have found a home on GitHub, which is focused on Git and used to have native support for RubyGems packaging.[32]
[edit] See also

Free software portal
Duck typing
Comparison of programming languages
Ruby MRI, the reference C implementation
JRuby
MacRuby
IronRuby
Rubinius
XRuby
Ruby on Rails
Why's (poignant) Guide to Ruby - an online ruby textbook in graphic novel format
Ruby wikibook
Metasploit Project - the world's largest Ruby project with over 700,000 lines of code
[edit] References
^ LICENSE.txt on Ruby official site
^ COPYING.txt on Ruby official site
^ http://www.ruby-lang.org/en/about/ Ruby-Lang About Ruby
^ a b http://www.linuxdevcenter.com/pub/a/linux/2001/11/29/ruby.html An Interview with the Creator of Ruby
^ http://www.youtube.com/watch?v=oEkJvvGEtB4 Google Tech Talks - Ruby 1.9
^ a b c http://blog.nicksieger.com/articles/2006/10/20/rubyconf-history-of-ruby History of Ruby
^ http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/88819 "[FYI: historic] The decisive moment of the language name Ruby. (Re: [ANN] ruby 1.8.1)" - Email from Hiroshi Sugihara to ruby-talk
^ http://eigenclass.org/hiki/ruby+0.95 More archeolinguistics: unearthing proto-Ruby
^ http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/382 "Re: history of ruby" - Email from Yukihiro Matsumoto to ruby-talk
^ http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/124 "TUTORIAL - ruby's features" - Email From Yukihiro Matsumoto to ruby-list
^ [1]
^ The Ruby Programming Language by Yukihiro Matsumoto on 2000-06-12 (informit.com)
^ a b c The Philosophy of Ruby, A Conversation with Yukihiro Matsumoto, Part I by Bill Venners on 2003-09-29 (Artima Developer)
^ Ruby Weekly News 23rd - 29th May 2005
^ An Interview with the Creator of Ruby
^ Dynamic Productivity with Ruby
^ martinfowler.com
^ [2][dead link]
^ Blocks and Closures in Ruby
^ Unicode support in Ruby is too buggy compared to similar programming languages
^ Green threads
^ Ruby FAQ
^ In Ruby's syntax, statement is just a special case of an expression which cannot appear as an argument (e.g. multiple assignment). http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/1120statement [...] can not be part of expression unless grouped within parentheses. http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/2460
^ http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/6745
^ Lam, John (2008-07-24). "IronRuby at OSCON". http://www.iunknown.com/2008/07/ironruby-at-oscon.html. Retrieved 2008-08-04. "We're shipping our first binary release. In this package, we're taking a "batteries included" approach and shipping the Ruby standard libraries in it"
^ Peter Cooper (2010-05-18). "The Why, What, and How of Rubinius 1.0's Release". http://www.rubyinside.com/the-why-what-and-how-of-rubinius-1-0-s-release-3261.html.
^ Charles Nutter (2008-04-27). "Promise and Peril for Alternative Ruby Impls". http://headius.blogspot.com/2008/04/promise-and-peril-for-alternative-ruby.html. Retrieved 2008-06-01.
^ John Lam (2008-05-25). "IronRuby / Rails Question". http://rubyforge.org/pipermail/ironruby-core/2008-May/001909.html. Retrieved 2008-05-25.
^ John Lam (2008-05-30). "IronRuby and Rails". http://www.iunknown.com/2008/05/ironruby-and-rails.html. Retrieved 2008-06-01.
^ "Iron Ruby on Windows Phone 7". http://msdn.microsoft.com/en-us/magazine/ff960707.aspx.
^ "Ruby 1.9 for Symbian OS". https://ella.pragmaticomm.com/symbian-ruby. Retrieved 2010-07-28.
^ Gem Building is Defunct, GitHub Blog
[edit] Bibliography
McAnally, Jeremy; Arkin, Assaf (March 28, 2009), Ruby in Practice (First ed.), Manning Publications, pp. 360, ISBN 1933988479, http://www.manning.com/mcanally/
Thomas, Dave; Fowler, Chad; Hunt, Andy (April 28, 2009), Programming Ruby 1.9: The Pragmatic Programmers' Guide (Third ed.), Pragmatic Bookshelf, pp. 1000, ISBN 1934356085, http://pragprog.com/titles/ruby3/programming-ruby-1-9
Flanagan, David; Matsumoto, Yukihiro (January 25, 2008), The Ruby Programming Language (First ed.), O'Reilly Media, pp. 446, ISBN 0596516177, http://oreilly.com/catalog/9780596516178/
Baird, Kevin (June 8, 2007), Ruby by Example: Concepts and Code (First ed.), No Starch Press, pp. 326, ISBN 1593271484, http://nostarch.com/ruby.htm
Fitzgerald, Michael (May 14, 2007), Learning Ruby (First ed.), O'Reilly Media, pp. 255, ISBN 0596529864, http://oreilly.com/catalog/9780596529864
Cooper, Peter (March 26, 2007), Beginning Ruby: From Novice to Professional (First ed.), Apress, pp. 664, ISBN 1590597664, http://apress.com/book/view/9781590597668
Fulton, Hal (November 4, 2006), The Ruby Way (Second ed.), Addison-Wesley Professional, pp. 888, ISBN 0596523696, http://www.informit.com/store/product.aspx?isbn=0672328844
Carlson, Lucas; Richardson, Leonard (July 19, 2006), Ruby Cookbook (First ed.), O'Reilly Media, pp. 906, ISBN 0596523696, http://oreilly.com/catalog/9780596523695/
[edit] External links
Wikimedia Commons has media related to: Ruby programming language
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The Great Ruby Shootout (December 2008): Ruby implementations comparison.
Collingbourne, Huw (June 17 2006), The Little Book Of Ruby, free PDF eBook 1.1MB, pp. 87
Collingbourne, Huw (April 18 2009), The Book Of Ruby, free PDF eBook 2.9MB, pp. 425
Ruby.on-page.net — simple Ruby manual with many samples
Ruby at the Open Directory Project
Ruby User Guide By Matz, the creator of Ruby. Translated into English.
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Wiki: Ruby language and implementation specification
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