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| - | {{Infobox programming language | + | <css> |
| - | |name = Ruby
| + | body { |
| - | |logo = [[Image:599px-Ruby logo.svg|100px]]
| + | background: #000 url(/skins/eqqon3/images/new_design_bg7.jpg) 0 0 no-repeat; |
| - | |paradigm = [[Multi-paradigm programming language|multi-paradigm]]
| + | } |
| - | |year = [[1995]]
| + | #eqqon3-header { |
| - | |designer = [[Yukihiro Matsumoto]]
| + | background: transparent url('/skins/eqqon3/images/header.png') left bottom no-repeat ; |
| - | |developer = Yukihiro Matsumoto (among others)
| + | position: relative; |
| - | |latest_release_version = 1.8.6
| + | min-height: 145px; |
| - | |latest_release_date = [[March 12]], [[2007]]
| + | height: 145px; |
| - | |typing = [[Type system|dynamic]] ([[Duck typing|"duck"]])
| + | margin: 0 auto; |
| - | |implementations = Ruby, [[JRuby]]
| + | padding: 0; |
| - | |dialects =
| + | } |
| - | |influenced_by = [[Smalltalk]], [[Perl]], [[Lisp programming language|Lisp]], [[Python (programming language)|Python]], [[CLU programming language|CLU]], [[Dylan programming language|Dylan]]
| + | .firstHeading { display: none; } |
| - | |influenced = [[Groovy programming language|Groovy]]
| + | #eqqon3-p-navigation-wrapper { width: 100%; } |
| - | |operating_system = [[Cross-platform]]
| + | </css> |
| - | |license = [http://www.ruby-lang.org/en/about/license.txt/ Ruby License] and [[GNU General Public License|GPL]]
| + | __NOTOC__ |
| - | |website = [http://www.ruby-lang.org www.ruby-lang.org]
| + | = = |
| - | }}
| + | <div style="margin-left:20px; float:right;"> |
| | + | <div style="border: 1px dotted; padding: 15px;" > |
| | + | ;Other articles by Henon |
| | + | *[[Git and CSharp|Using Git on Windows]] <small>(June 2009)</small> |
| | + | *[[Closing the Gap Between IEnumerator and IEnumerable]] <small>(20 April 2008)</small> |
| | + | *[[Asynchronous Events]] <small>(19 December 2007)</small> |
| | + | *[[Design For Reuse]] <small>(7 December 2007)</small> |
| | + | *[[Preventing Recursive Events|Preventing Recursive Events in C#]] <small>(21 November 2007)</small> |
| | + | *[[Visitor Pattern]] <small>(21 November 2007)</small> |
| | + | *[[Navigating in Exception Stack Traces in Visual C-Sharp|Navigating in Exception Stack Traces in Visual C#]] <small>(9 November 2007)</small> |
| | + | *[[Ruby-like instance variable syntax in C-Sharp|Ruby-like instance variable syntax in C#]] <small>(30 October 2007)</small> |
| | + | *[[Streaming between Threads or Processes]] <small>(30 October 2007)</small> |
| | + | *[[The Future of Ruby]] <small>(6 August 2007)</small> |
| | + | ;Publications |
| | + | * [http://www.cg.tuwien.ac.at/~pm/FacadeRepair/ Symmetry-Based Facade Repair] <small>(October 2009)</small> |
| | + | * [http://www.eqqon.com/images/b/b3/Realtime_ray_tracing.pdf Realtime Ray Tracing (pdf)]<small>(June 2007)</small> |
| | + | * [http://stud4.tuwien.ac.at/~e0026003/netvis/ TU Netvis - Visual Network Traffic Administration] <small>(March 2006)</small> |
| | + | * [http://stud4.tuwien.ac.at/~e0026003/art/presentation.html Meinrad Recheis Abstraktionen] My Art Work between 2001 and 2003 <small>(2003)</small> |
| | + | ;Links |
| | + | *[[:Category:CSharp|C# Knowhow]] |
| | + | *[[Piccolo Snippets]] |
| | + | </div> |
| | + | </div> |
| | | | |
| - | '''Ruby''' is a [[reflection (computer science)|reflective]], [[dynamic programming language|dynamic]], [[object-oriented programming language]]. It combines syntax inspired by [[Perl]] with [[Smalltalk]]-like object-oriented features, and also shares some features with [[Python (programming language)|Python]], [[Lisp (programming language)|Lisp]], [[Dylan (programming language)|Dylan]], and [[CLU (programming language)|CLU]]. Ruby is a single-pass [[interpreted language]]. Its official implementation is [[free software]] written in [[C (programming language)|C]].
| + | <big><big><big><span style="color:#fff;padding-left:80px; font-weight:900; background-color:#000;"> Henon's Blog</span> </big></big></big> |
| | | | |
| - | == History == | + | <div style="margin-left:80px; margin-right:80px; margin-top:80px"> |
| - | The language was created by [[Yukihiro Matsumoto|Yukihiro "Matz" Matsumoto]], who started working on Ruby on [[February 24]], [[1993]], and released it to the public in [[1995]]. "Ruby" was named after a colleague's [[birthstone]]. As of [[March 2007]], the latest stable version is 1.8.6. Ruby 1.9 (with some major changes) is also in development. Performance differences between the current Ruby implementation and other more entrenched programming languages has led to the development of several virtual machines for Ruby. These include [[JRuby]], a port of Ruby to the [[Java (programming language)|Java]] platform, [[IronRuby]], an implementation for the [[.NET Framework]] produced by [[Microsoft]], and [[Rubinius]], an interpreter modeled after self-hosting [[Smalltalk]] virtual machines. The main developers have thrown their weight behind the virtual machine provided by the [[YARV]] project, which was merged into the Ruby source tree on [[31 December]] [[2006]], and will be released as Ruby 2.0.
| + | |
| | | | |
| - | == Philosophy == | + | = <span style= "margin-left:-30px;">I love WPF</span> = |
| - | The language's creator has said that Ruby is designed for programmer productivity and fun, following the principles of good [[user interface]] design.<ref>[http://www.informit.com/articles/article.asp?p=18225 The Ruby Programming Language by Yukihiro Matsumoto on 2000-06-12 (informit.com)]</ref> He stresses that systems design needs to emphasize human, rather than computer, needs <ref>[http://www.artima.com/intv/ruby4.html The Philosophy of Ruby, A Conversation with Yukihiro Matsumoto, Part I by Bill Venners on 2003-09-29 (Artima Developer)]</ref>:
| + | <br> |
| | + | <br> |
| | + | I love WPF because ... |
| | + | * ... WPF doesn't restrict my creativity as much as other toolkits do. |
| | + | * ... WPF makes me feel powerful. |
| | + | * ... I am a WPF guru and others are respecting me ;) |
| | | | |
| - | {{cquote|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.}}
| + | I hate WinForms because ... |
| | + | * ... Form's class design is nuts, |
| | + | * ... every programmer could easily hack together standard GUIs, nobody needs a GUI-guru like me ;) |
| | + | * ... it is frustratingly complex to achieve visually rich displays. |
| | | | |
| - | Ruby is said to follow the [[principle of least surprise]] (POLS), meaning that the language should behave in such a way as to minimize confusion for experienced users. Matz 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 he hadn't applied the principle of least surprise to the design of Ruby,<ref>[http://www.artima.com/intv/ruby4.html The Philosophy of Ruby, A Conversation with Yukihiro Matsumoto, Part I by Bill Venners on 2003-09-29 (Artima Developer)]</ref> 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, Matz attempts to distance Ruby from POLS, explaining that since 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. [http://www.rubyweeklynews.org/20050529]
| + | = <span style= "margin-left:-30px;">Hommage à _why</span> = |
| | + | <br> |
| | + | <br> |
| | + | A man only known by his nick name [http://en.wikipedia.org/wiki/Why_the_lucky_stiff Why_the_lucky_stiff] or just ''_why'' was one of the most productive and creative members of the Ruby community and I admired him. He wrote several libraries and a delicately illustrated book on the Ruby Language [http://en.wikipedia.org/wiki/Why%27s_%28poignant%29_Guide_to_Ruby]. Then suddenly, _why dissappeared, all his accounts had been deleted. |
| | | | |
| - | Matz defined it this way in an interview [http://www.artima.com/intv/ruby4.html]:
| + | Many theories have been issued as to what happened. My theory is, that the person behind ''Why_the_lucky_stiff'' couldn't bear to maintain the online presence he'd created any more. I think, he found himself another goal in life that stands in concurrence with his online activities. Without doubt being a person who puts all his energy into his goals, he had to choose between the one and the other. He made a clean cut, made his decision final by destroying his alter ego. I wouldn't be surprised if it was for love after all. |
| - | {{cquote|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. 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.}}
| + | |
| | | | |
| - | == Semantics ==
| + | To express my appreciation for Why_the_lucky_stiff, I made one last episode of his legendary foxes<br><br> |
| - | Ruby is [[object-oriented]]: every data type is an object, including even classes and types that many other languages designate as primitives (such as [[integer]]s, booleans, and "nil"). Every [[function (programming)|function]] is a [[method (programming)|method]]. Named values (variables) always designate references to objects, not the objects themselves. Ruby supports [[inheritance (object-oriented programming)|inheritance]] with [[dynamic dispatch]], [[mixin]]s and [[singleton pattern|singleton method]]s (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 [[module (programming)|module]]s as mixins. Procedural syntax is supported, but all methods defined outside of the scope of a particular object are actually methods of the Object class. Since this class is parent to every other class, the changes become visible to all classes and objects.
| + | [[Image:Hommage a why the lucky stiff.png|700px]] |
| | + | <br><br> |
| | + | <div style="width:280px;margin:50px;padding:10px;border:1px solid;background:white;margin-top:100px;float:right"> |
| | | | |
| - | Ruby has been described as a [[multi-paradigm programming language]]: it allows you to program procedurally (defining functions/variables outside classes makes them part of the root, 'self' Object), with object orientation (everything is an object) or [[Functional programming|functionally]] (it has anonymous functions, [[Closure (computer science)|closures]], and [[continuation]]s; statements all have values, and functions return the last evaluation). It has support for [[Introspection (computer science)|introspection]], [[Reflection (computer science)|reflection]] and [[metaprogramming]], as well as support for [[Thread (computer science)|thread]]s<ref>Though is only support [[Green threads]]</ref>. Ruby features [[Type system|dynamic typing]], and supports [[Polymorphism in object-oriented programming|parametric polymorphism]].
| + | [[Image:You want some tsingtao stout small.jpg]] |
| | | | |
| - | According to the Ruby [[FAQ]] <ref>[http://faq.rubygarden.org/ Ruby FAQ]</ref>, "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 (programming language)|Python]], you may or may not be put off by the huge difference in design philosophy between Python and Ruby/Perl." <ref>[http://faq.rubygarden.org/entry/show/14 How Does Ruby Compare With Python? (FAQ)]</ref>
| + | "Want some TSINGTAO Stout?". Me chewing on something good, with chop sticks, drinking the best Chinese beer there is. |
| | + | </div> |
| | | | |
| - | == Features == | + | = <span style= "margin-left:-30px;">Thoughts on Circular Dependencies in Software Design</span> = |
| - | * [[object-oriented]]
| + | <br> |
| - | * four levels of variable scope: [[Global variable|global]], class, instance, and local
| + | <br> |
| - | * [[exception handling]]
| + | ;Definition |
| - | * [[iterator]]s and [[closure (computer science)|closures]] (based on passing blocks of code)
| + | A Circular Dependency in a software design is a mutual dependency between two modules which either directly or indirectly depend on each other to function properly. In many cases circular dependencies are perfectly sensible such as a dependency between an Employee class and a Company class where the employing company has a list of employees and each employee has a back-reference to its employer. This circular dependency models a mutual dependency of the domain. Circular dependencies between unrelated modules are considered a bad software design praxis, though. An example for a bad circular dependency would be to have a general Person class instead of an Employee class which inherits from Person and the Company class has references to Persons (which is ok) and the Person has a back-reference to its employing Company (not ok!). |
| - | * native, [[Perl]]-like [[regular expression]]s at the language level
| + | |
| - | * [[operator overloading]]
| + | |
| - | * [[garbage collection (computer science)|automatic garbage collecting]]
| + | |
| - | * highly [[porting|portable]]
| + | |
| - | * cooperative [[multi-threading]] on all platforms using [[Green threads]]
| + | |
| - | * [[Dynamic-Link Library|DLL]]/[[Library (computer science)|shared library]] dynamic loading on most platforms
| + | |
| - | * introspection, [[Reflection (computer science)|reflection]] and [[metaprogramming]]
| + | |
| - | * large standard library
| + | |
| - | * supports [[dependency injection]]
| + | |
| - | * [[continuation]]s and [[Generator (computer science)|generators]] (examples in RubyGarden: [http://www.rubygarden.org/ruby?Continuations continuations] and [http://www.rubygarden.org/ruby?RubyFromPython generators])
| + | |
| - | | + | |
| - | Ruby currently lacks full support for [[Unicode]], though it has partial support for [[UTF-8]].
| + | |
| - | | + | |
| - | === Interaction ===
| + | |
| - | The Ruby official distribution also includes "irb", an interactive command-line interpreter which can be used to test code quickly. A session with this interactive program might be:
| + | |
| - |
| + | |
| - | $ irb
| + | |
| - | irb(main):001:0> puts "Hello, World"
| + | |
| - | Hello, World
| + | |
| - | => nil
| + | |
| - | irb(main):002:0> 1+2
| + | |
| - | => 3
| + | |
| - | | + | |
| - | == 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 (computer programming)|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 }). 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 significant improvements over Python and Perl is Ruby's ability to keep its variables private to the class and only expose them through accessor methods (attr_writer, attr_reader, etc). These methods, unlike other languages like C++ or Java, can be written with a single line of code. As invocation of these methods does not require the use of parenthesis, 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 or Python's property descriptors.
| + | |
| - | | + | |
| - | See the ''[[#Examples|examples]]'' section for samples of code demonstrating Ruby syntax.
| + | |
| - | | + | |
| - | =="Gotchas"==
| + | |
| - | Some features that differ notably from languages such as [[C (programming language)|C]] or [[Perl]]:
| + | |
| - | | + | |
| - | * Names that begin with a capital letter are treated as constants, so local variables should begin with a lowercase letter.
| + | |
| - | * To denote floating point numbers, one must follow with a zero digit (<code>99.0</code>) or an explicit conversion (<code>99.to_f</code>). It is insufficient to append a dot (<code>99.</code>) because numbers are susceptible to method syntax.
| + | |
| - | * [[Boolean datatype|Boolean]] evaluation of non-boolean data is strict: 0, <code>""</code> and <code>[]</code> are all evaluated to ''true''. In C, the expression <code>0 ? 1 : 0</code> evaluates to 0 (i.e. false). In Ruby, however, it yields 1, as all numbers evaluate to true; only <code>nil</code> and <code>false</code> evaluate to ''false''. A corollary to this rule is that Ruby methods by convention — for example, [[regular expression|regular-expression]] searches — return numbers, strings, lists, or other non-false values on success, but <code>nil</code> on failure (e.g., mismatch). This convention is also used in Smalltalk, where only the special objects <code>true</code> and <code>false</code> can be used in a boolean expression.
| + | |
| - | * Versions prior to 1.9 lack a character data type (compare to C, which provides type <code>char</code> for characters). This may cause surprises when slicing strings: <code>"abc"[0]</code> yields 97 (an integer, representing the [[ASCII]] code of the first character in the string); to obtain <code>"a"</code> use <code>"abc"[0,1]</code> (a substring of length 1) or <code>"abc"[0].chr</code>.
| + | |
| - | * The notation "statement until expression", despite the English-language implication that statement would be executed at least once, and precedent in other languages' equivalent statements (e.g. "do { statement } while (not(expression));" in C/C++/...), actually never runs the statement if the expression is already true.
| + | |
| - | | + | |
| - | In addition, some issues with the language itself are commonly raised:
| + | |
| - | * In terms of speed, Ruby's performance is inferior to that of many compiled languages (as is any interpreted language) and other major scripting languages such as [[Python (programming language)|Python]] and [[Perl]]<ref name="alioth">[http://shootout.alioth.debian.org/ The Computer Language Benchmarks Game]</ref>. However, in future releases (current revision: 1.9), Ruby will be [[bytecode|bytecode compiled]] to be executed on [[YARV]] (''Yet Another Ruby VM''). Currently, Ruby's memory footprint for the same operations is better than Perl's and Python's.<ref name="alioth" />
| + | |
| - | * Omission of parentheses around method arguments may lead to unexpected results if the methods take multiple parameters. Note that the Ruby developers have stated that omission of parentheses on multi-parameter methods may be disallowed in future Ruby versions. Much existing literature, however, encourages parenthesis omission for single-argument methods.
| + | |
| - | | + | |
| - | Unlike [[Python (programming language)|Python]], Ruby doesn't have a syntax for named arguments in function invocation (calling a function by <code>some_function(y=4, x=5)</code> simply assigns <code>4</code> and <code>5</code> to the local variables <code>y</code> and <code>x</code>). This is easily and frequently emulated by passing hashes: <code>some_function(:y => 4, :x => 5)</code>, however, and extracting the arguments by name inside the function, similar to Perl.
| + | |
| - | | + | |
| - | A list of "[[gotcha]]s" 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. <code>retry</code>, for example, now works with <code>while</code>, <code>until</code>, and <code>for</code>, as well as iterators.
| + | |
| - | | + | |
| - | == Examples ==
| + | |
| - | 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
| + | |
| - | "Rick".index("c") # 2
| + | |
| - | "Nice Day Isn't It?".downcase!.split(//).uniq.sort.join # " '?acdeinsty"
| + | |
| - | | + | |
| - | === Collections ===
| + | |
| - | Constructing and using an [[array]]:
| + | |
| - | a = <nowiki>[1, 'hi', 3.14, 1, 2, [4, 5]]</nowiki>
| + | |
| | | | |
| - | a[2] # 3.14
| + | ;Significance |
| - | a.reverse # <nowiki>[[4, 5], 2, 1, 3.14, 'hi', 1]</nowiki>
| + | Circular dependencies should be avoided if possible in software design because of their negative effects. Some of these effects are: |
| - | a.flatten.uniq # <nowiki>[1, 'hi', 3.14, 2, 4, 5]</nowiki>
| + | * a circular dependency can be a "breach of encapsulation" (see Encapsulation) |
| - | | + | * a circular dependency tightly couples two or more modules making each of them unable to be reused in other places without dragging in dependencies on the others. |
| - | Constructing and using a [[hash table|hash]]:
| + | * circular dependencies can be the cause of a so called "domino effect" which describes what happens when a small change in software that is supposed to be a local change spreads into other modules and has unwanted global effects (i.e. program errors, compile errors). |
| - |
| + | * a circular dependency might result in infinite recursions or in failures in software programs |
| - | hash = {:water => 'wet', :fire => 'hot'}
| + | * a circular dependency is a "refactoring smell" which may indicate a bad software design |
| - | <nowiki>puts hash[:fire]</nowiki> # 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_if {|key, value| key == :water} # Deletes :water => 'wet'
| + | |
| - | | + | |
| - | === '''Blocks and iterators''' ===
| + | |
| - | The two syntaxes for creating a code block:
| + | |
| - | { puts "Hello, World!" } # Note the { braces }
| + | |
| - |
| + | |
| - | do puts "Hello, World!" end
| + | |
| - | Parameter-passing a block to be a [[Closure (computer science)|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 that takes a name.
| + | |
| - | remember {|name| puts "Hello, #{name}!"}
| + | |
| - |
| + | |
| - | # When the time is right (for the object) -- call the closure!
| + | |
| - | @block.call("Jon")
| + | |
| - | # => "Hello, Jon!"
| + | |
| - | | + | |
| - | 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
| + | |
| - | | + | |
| - | 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
| + | |
| - |
| + | |
| - | (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 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:
| + | |
| - | (1..10).collect {|x| x*x} # => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
| + | |
| - | | + | |
| - | === 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 <code>Array#sort</code> can sort by age) and the other to override the <code>to_s</code> method (so <code>Kernel#puts</code> can format its output). Here, "<code>attr_reader</code>" is an example of metaprogramming in Ruby: "<code>attr_accessor</code>" defines getter and setter methods of instance variables, "<code>attr_reader</code>" only getter methods. Also, the last evaluated statement in a method is its return value, allowing the omission of an explicit 'return'.
| + | |
| - | | + | |
| - | class Person
| + | |
| - | 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
| + | |
| - |
| + | |
| - | attr_reader :name, :age
| + | |
| - | end
| + | |
| - |
| + | |
| - | group = <nowiki>[</nowiki> Person.new("Jon", 20),
| + | |
| - | Person.new("Marcus", 63),
| + | |
| - | Person.new("Ash", 16)
| + | |
| - | <nowiki>]</nowiki>
| + | |
| - |
| + | |
| - | puts group.sort.reverse
| + | |
| - | | + | |
| - | The above prints three names in reverse age order:
| + | |
| - | Marcus (63)
| + | |
| - | Jon (20)
| + | |
| - | Ash (16)
| + | |
| - | | + | |
| - | === Exceptions ===
| + | |
| - | An exception is raised with a <code>raise</code> 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!"
| + | |
| - | | + | |
| - | Exceptions are handled by the <code>rescue</code> clause. Such a clause can catch exceptions that inherit from StandardError:
| + | |
| - | begin
| + | |
| - | # Do something
| + | |
| - | rescue
| + | |
| - | # Handle exception
| + | |
| - | end
| + | |
| - | Note that 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 -- this only catches StandardError, a subclass of Exception
| + | |
| - | # Handle exception
| + | |
| - | end
| + | |
| - | | + | |
| - | Or catch particular exceptions:
| + | |
| - | begin
| + | |
| - | # ...
| + | |
| - | rescue RuntimeError
| + | |
| - | # handling
| + | |
| - | end
| + | |
| - | Finally, it is possible to specify that the exception object be made available to the handler clause:
| + | |
| - | begin
| + | |
| - | # ...
| + | |
| - | rescue RuntimeError => e
| + | |
| - | # handling, possibly involving e
| + | |
| - | end
| + | |
| - | Alternatively, the most recent exception is stored in the magic global <code>$!</code>.
| + | |
| - | | + | |
| - | === More examples ===
| + | |
| - | More sample Ruby code is available as algorithms in the following articles:
| + | |
| - | * [[Exponentiating by squaring]]
| + | |
| - | * [[Associative array#Ruby|Ruby associative arrays]]
| + | |
| - | * [[Trabb Pardo-Knuth algorithm]]
| + | |
| - | | + | |
| - | == Implementations ==
| + | |
| - | Ruby has two main implementations: the official Ruby [[interpreter (computer software)|interpreter]], which is the most widely used, and [[JRuby]], a [[Java (programming language)|Java]]-based implementation.
| + | |
| - | | + | |
| - | There are other less known implementations such as [[IronRuby]] (still unreleased yet), [[Rubinius]], [[XRuby]] and [[YARV]]. YARV is sometimes referred as the next official Ruby engine.
| + | |
| - | | + | |
| - | === Operating systems ===
| + | |
| - | Ruby is available for the following [[operating system]]s:
| + | |
| - | | + | |
| - | * [[Acorn Computers Ltd|Acorn]] [[RISC OS]]
| + | |
| - | * [[Amiga]]
| + | |
| - | * [[BeOS]]
| + | |
| - | * [[DOS]]
| + | |
| - | * [[Linux]]
| + | |
| - | * [[Mac OS X]]
| + | |
| - | * [[Microsoft Windows]] 95/98/XP/NT/2000/2003/Vista
| + | |
| - | * Microsoft [[Windows CE]]
| + | |
| - | * [[MorphOS]]
| + | |
| - | * [[OS/2]]
| + | |
| - | * [[OpenVMS]]
| + | |
| - | * [[Syllable (operating system)|Syllable]]
| + | |
| - | * [[Symbian_os|Symbian OS]]
| + | |
| - | * [[Blue Gene/L]] compute node kernel
| + | |
| - | * Most flavors of [[Unix]]
| + | |
| - | | + | |
| - | Other ports may also exist.
| + | |
| - | | + | |
| - | === Licensing terms ===
| + | |
| - | The Ruby interpreter and libraries are distributed disjointedly ([[dual licensed]]) under the [[Free software|free]] and [[open source]] licenses [[GNU General Public License|GPL]] and Ruby License <ref>[http://www.ruby-lang.org/en/LICENSE.txt Ruby License (ruby-lang.org)]</ref>.
| + | |
| - | | + | |
| - | | + | |
| - | | + | |
| - | ==Criticism==
| + | |
| - | The current 1.8 version of Ruby main interpreter has some limitations. On 1 January 2007, work has begun for version 1.9 which will produce Ruby 2.0 later in 2007 or in 2008. The problems of the current stable version include:
| + | |
| - | * As a dynamic scripting language, Ruby's speed is much less than that of other languages, including scripting languages such as [[Perl]], [[PHP]], or [[Python (programming language)|Python]] [http://shootout.alioth.debian.org/gp4/benchmark.php?test=all&lang=all] [http://www.joelonsoftware.com/items/2006/09/12.html] - however, the next version of Ruby will include a new faster interpreter, [[YARV]]
| + | |
| - | * The Ruby threading model uses [[Green threads]] [http://www.headius.com/rubyspec/index.php/Ruby_Threading], and its model has some inherent limitations that render it difficult to use or unsafe for some user-case scenarios [http://www.killersites.com/blog/2007/standalone-ruby-on-rails/] - however, version 2.0 of Ruby will not implement green threads. | + | |
| - | * Ruby does not yet have native support for [[Unicode]] or multibyte strings [http://headius.blogspot.com/2006/06/unicode-in-ruby-unicode-in-jruby.html] - should be included in version 2.0 though.
| + | |
| - | | + | |
| - | Some problems that may not be solved in version 2.0 include:
| + | |
| - | * Ruby still lacks a specification, the current reference specification being ''de facto'' the C implementation [http://headius.blogspot.com/2007/04/what-would-i-will-i-change-about-ruby.html] [http://craigrandall.net/archives/2006/09/from-java-to-ruby/] .
| + | |
| - | | + | |
| - | == 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 two thousand items. Although the number of applications available does not match the volume of material available in the [[Perl]] or [[Python (programming language)|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]].
| + | |
| - | | + | |
| - | == References ==
| + | |
| - | <references/>
| + | |
| - | | + | |
| - | == See also ==
| + | |
| - | {{portalpar|Free software}}
| + | |
| - | * [[Duck typing]] | + | |
| - | * [[RubyGems]] (a Ruby package manager)
| + | |
| - | * [[Ruby on Rails]] (a Ruby web application framework)
| + | |
| - | * [[Ruby Application Archive]]
| + | |
| - | * [[Interactive Ruby Shell]]
| + | |
| - | * [[IronRuby]], a CIL-compiled version of Ruby for .NET Framework
| + | |
| - | * [[Comparison of programming languages]]
| + | |
| - | * [[Watir]]
| + | |
| - | * [[JRuby]] (a pure Java implementation of the Ruby interpreter)
| + | |
| - | * [[RadRails]] Ruby/Rails IDE (based on [[Eclipse_%28software%29|Eclipse]])
| + | |
| - | * [[Rinda]] (parallel programming extension for Ruby)
| + | |
| | | | |
| - | == External links == | + | = <span style= "margin-left:-30px;">Browse Ad Free with Google Chrome</span> = |
| - | {{Wikibooks|Ruby Programming}}
| + | <br> |
| - | {{Wikiversity|Topic:Ruby}}
| + | <br> |
| | + | Everyone agrees that Google's new browser called Chrome is really innovative, fast and cool. But as soon as you try it out, you will hate it for happily displaying all the banners, ads, overlays etc. Not blocking ads is, of course, the full intent of Google and possibly one of the main reasons for introducing a new browser instead of further supporting Firefox because they may have noticed that their ads don't reach firefox users who almost all are using the popular Mozilla extension AdBlock (Plus). |
| | | | |
| - | *[http://www.ruby-lang.org/en/ Ruby language home page]
| + | Loving the new concepts of Chrome and also being stunned by its well designed user interface, I have looked around for adblocking support. Here is what I found out: |
| - | *[http://tryruby.hobix.com Test Ruby knowledge online]
| + | * Google does '''not''' deliver an adblocking plugin for Chrome. |
| - | *[http://dmoz.org/Computers/Programming/Languages/Ruby/ Ruby programming language] at the [[Open Directory Project]]
| + | * forget AdMuncher it's not free. |
| - | *[http://groups.google.com/group/comp.lang.ruby comp.lang.ruby Usenet group]
| + | * forget Privoxy it's way too complicated |
| - | *[http://ruby.on-page.net Ruby.on-page.net — the simplest Ruby manual]
| + | * forget HostsMan it doesn't work anyway |
| - | *[http://www.eclipse.org/dltk/ Eclipse Dynamic Languages Toolkit] for Ruby, IDE with intellisense features like type inference and smart code completion. | + | |
| - | *[http://www.railslodge.com Ruby on Rails plugin directory and job board] | + | |
| - | *[http://www.meshplex.org/wiki/Ruby/Ruby_on_Rails_programming_tutorials Full Ruby on Rails Tutorial] - A complete beginners intro to Ruby on Rails | + | |
| - | *[http://www.mentalpointer.com/ruby/index.html Ruby User Guide Mirror] | + | |
| - | *[http://www.google.com/codesearch?hl=en&lr=&q=lang%3Aruby&btnG=Search Find Ruby with Google Code Search]
| + | |
| | | | |
| - | [[Category:Free compilers and interpreters]] | + | I strongly suggest you to use ----> [http://bfilter.sourceforge.net BFilter] <------ . It's totally painless to install, no setup required and it works instantly (after adjusting the browser's proxy settings). Knows a lot of adservers and works like a charm even for german ads. Adding rules is straight forward, as we are used to with AdblockPlus. |
| - | [[Category:Class-based programming languages]]
| + | |
| - | [[Category:Dynamically-typed programming languages]]
| + | |
| - | [[Category:Object-oriented programming languages]]
| + | |
| - | [[Category:Programming languages]]
| + | |
| - | [[Category:Scripting languages]]
| + | |
| - | [[Category:Ruby programming language| ]]
| + | |
| - | [[Category:Curly bracket programming languages]]
| + | |
| - | [[Category:Articles with example Ruby code]]
| + | |
| - | [[Category:Software by language]]
| + | |
| | | | |
| - | <!-- interwiki -->
| + | OK, here is what to do: |
| | + | * install BFilter |
| | + | * set Chrome's proxy settings to 127.0.0.1 port 8080 (via Options -> Under the Hood -> Change Proxy Settings -> LAN Settings -> Check "Use a proxy server for your LAN") |
| | + | * '''enjoy Chrome adfree!''' |
| | + | --[[User:Henon|Henon]] 11:48, 11 September 2008 (CEST) |
| | | | |
| - | [[ar:روبي (لغة برمجة)]]
| + | </div> |
| - | [[bg:Ruby]]
| + | |
| - | [[ca:Ruby]]
| + | |
| - | [[cs:Ruby]]
| + | |
| - | [[da:Ruby (programmeringssprog)]]
| + | |
| - | [[de:Ruby (Programmiersprache)]]
| + | |
| - | [[es:Ruby]]
| + | |
| - | [[eo:Ruby (programlingvo)]]
| + | |
| - | [[eu:Ruby]]
| + | |
| - | [[fa:روبی]]
| + | |
| - | [[fr:Ruby]]
| + | |
| - | [[gl:Ruby]]
| + | |
| - | [[ko:루비 프로그래밍 언어]]
| + | |
| - | [[hr:Ruby (programski jezik)]]
| + | |
| - | [[id:Ruby]]
| + | |
| - | [[ia:Ruby (linguage de programmation)]]
| + | |
| - | [[it:Ruby]]
| + | |
| - | [[he:Ruby]]
| + | |
| - | [[ka:რუბი (პროგრამირების ენა)]]
| + | |
| - | [[ku:روبی]]
| + | |
| - | [[lt:Ruby]]
| + | |
| - | [[hu:Ruby programozási nyelv]]
| + | |
| - | [[nl:Ruby (programmeertaal)]]
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| - | [[ja:Ruby]]
| + | |
| - | [[no:Ruby]]
| + | |
| - | [[nn:Ruby]]
| + | |
| - | [[pl:Ruby (język programowania)]]
| + | |
| - | [[pt:Ruby (linguagem de programação)]]
| + | |
| - | [[ro:Ruby]]
| + | |
| - | [[ru:Ruby]]
| + | |
| - | [[ru-sib:Руби (перекатной говор)]]
| + | |
| - | [[sr:Програмски језик Руби]]
| + | |
| - | [[fi:Ruby]]
| + | |
| - | [[sv:Ruby]]
| + | |
| - | [[ta:ரூபி]]
| + | |
| - | [[th:ภาษารูบี้]]
| + | |
| - | [[vi:Ruby (ngôn ngữ lập trình)]]
| + | |
| - | [[bat-smg:Ruby]]
| + | |
| - | [[zh:Ruby]]
| + | |
