Crystal (programming language): Difference between revisions

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{{Short description|Object-oriented programming language}}

{{Infobox programming language

| name = Crystal

| logo = Crystal language logo.svg

|logo = The_Crystal_programming_language_logo.svg

| paradigm = [[Multi-paradigm programming language|Multi-paradigm]]: [[Object-oriented programming|object-oriented]], [[Concurrent computing|concurrent]]

|logo size = 260px

| released = {{Start date and age|2014|06|19}}<ref>{{Cite web|url=https://crystal-lang.org/2014/06/19/crystal-0.1.0-released.html|title=Crystal 0.1.0 released!|website=crystal-lang|date=19 June 2014 }}</ref>

| paradigm = [[Multi-paradigm programming language|Multi-paradigm]]: [[Object-oriented programming|Object-oriented]]

| designer = Ary Borenszweig, Juan Wajnerman, Brian = Ary BorenszweigCardiff

| developer = Manas Technology Solutions

| latest previewrelease version = 0.19.4{{wikidata|property|preferred|references|edit|P348|P548=Q2804309}}

| latest previewrelease date = {{Start date and age|2016{{wikidata|10qualifier|07preferred|single|P348|P548=Q2804309|P577}}|df=yes}}

| typing = [[Type system#Static type =checking|static]], [[Type system#StaticInferred type checking|staticinferred]], [[Nominal type system|nominal]], [[Duck_typing|duck]]

| influenced by = [[Ruby (programming language)|Ruby]], [[Go (programming language)|Go]]<ref name="go multithread" Crystal/>

| programming language = Crystal

| platform = '[[IA-32]]' (i386), '[[x86-64]]'

| operating system platform = [[OS XIA-32]] (i386), [[Linuxx86-64]], [[FreeBSDAArch64]]<ref name="platform-support" />

| operating system = [[Linux]], [[macOS]], [[FreeBSD]], [[OpenBSD]], [[Microsoft Windows|Windows]]<ref name="platform-support" />

| license = [[Apache License]] 2.0

| license = [[Apache License 2.0]]

| file ext = .cr

| file ext = .cr

| website = {{URL|https://crystal-lang.org/}}

| website = {{URL|https://crystal-lang.org}}}}

| influenced by = [[Ruby (programming language)|Ruby]],<ref name="rel_0.18.0"/> [[C (programming language)|C]], [[Rust (programming language)|Rust]], [[Go (programming language)|Go]],<ref name="rel_0.18.0"/> [[C Sharp (programming language)|C#]],<ref name="rel_0.18.0"/> [[Python (programming language)|Python]]<ref name="rel_0.18.0"/>

}}

'''Crystal''' is a [[high-level programming language|high-level]] [[general-purpose programming language|general-purpose]], [[object-oriented programming language|object-oriented]] programming language, designed and developed by Ary Borenszweig and, Juan Wajnerman, Brian Cardiff and overmore one-hundredthan listed400 contributors.<ref>[https://github.com/manastech/crystal Crystalname="contributors" source code]</ref> CrystalWith issyntax developedinspired as open source software (underby the language [[ApacheRuby License(programming language)|Ruby]],<ref Version 2name="rel_0.18.0)"/> withit syntaxis inspired bya [[Ruby (programmingcompiled language)|Ruby]]. Thewith language[[Type issystem#Static staticallytype checking|static type-checkedchecking]], but does not require thatspecifying the typetypes of variables or method arguments beis generally specifiedunneeded. ThisTypes isare theresolved resultby ofan advanced global [[type inference]] algorithm.<ref>[http://crystal-lang.org/2013/09/23/ name="type-inference-part-1.htmli" Type/><ref inferencename="devm" part 1]</ref> TheCrystal language is in an active development phase.

is currently in active development. It is released as [[free and open-source software]] under the [[Apache License]] version 2.0.

== History ==

Work on the language began in June 2011,<ref name="story"/> with the purposeaim of creating a language which hadmerging the elegance and productivity of Ruby andwith the speed, efficiency, and type safety of a compiled language.<ref name="why_crystal"/><ref name="story"/> Initially callednamed ''Joy'', it was quickly renamed to ''Crystal''.<ref name="story"/>

In November 2013, theThe Crystal compiler (previouslywas first written in Ruby), becamebut later rewritten in Crystal, thus becoming [[Self-hosting (compilers)|self-hosting]], {{as of|November 2013|lc=true}}.<ref name="goodbye_ruby"/> The first official version was released in June 2014.<ref name="rel_0.1.0"/> In July 2016, Crystal was added tojoined the [[TIOBE index|TIOBE Index]].

== Description ==

Although resembling the Ruby programming language in syntax, Crystal compiles to much more efficient native code using an [[LLVM]] backend, at the cost of disallowingprecluding the dynamic aspects of Ruby. However, theThe advanced global type inference used by the Crystal compiler, combined with the usage of [[union type]]s, givegives Crystalit more the feel of a higher-level scripting language than many other comparable programming languages. Recent benchmarks have demonstrated that Crystal has a performance broadly similar to [[C (programming language)|C]] for a wide range of computing tasks.<ref>[https://github.com/kostya/benchmarks Some benchmarks of different languages]</ref><ref>[https://github.com/kostya/crystal-benchmarks-game Crystal implementations for The Computer Language Benchmarks Game]</ref><ref>[https://github.com/smarr/are-we-fast-yet/tree/master/benchmarks/Crystal Are We Fast Yet?]</ref> The languageIt has automated garbage collection and currently offers a [[Boehm garbage collector|Boehm collector]]. Crystal possesses a macro system and supports generics andas well as method and operator overloading. Crystal'sIts concurrency model is inspired by [[communicating sequential processes]] (CSP), and implements light-weightlightweight fibers and channels (for communicatinginterfiber between fiberscommunication), inspired by the [[Go (programming language)|Go programming language]].<ref name = "rel_0go multithread">{{cite web | url=https://forum.18crystal-lang.0"org/t/crystal-multithreading-support/6622/19 | title=Crystal multithreading support | date=23 February 2024 }}</ref>

== Examples ==

=== Hello World ===

This is the simplest way to write the [["Hello, World!" program|Hello World]] program in Crystal:

<syntaxhighlight lang="crystal">

=== [[Hello World]] ===

This is the simplest way to write the Hello World program in Crystal:

<syntaxhighlight lang="ruby">

puts "Hello World!"

</syntaxhighlight>

The same as in Ruby.

Or using an [[object-oriented programming]] style:

<syntaxhighlight lang="rubycrystal">

class Greeter

def initialize(@name : String)

@name = name

end

Line 54:

</syntaxhighlight>

=== HTTP Serverserver ===

<syntaxhighlight lang="crystal">

<syntaxhighlight lang="ruby">

require "http/server"

server = HTTP::Server.new(8080) do |context|

context.response.content_type = "text/plain"

context.response.print "Hello world! The time is #{Time.nowlocal}"

end

server.bind_tcp("0.0.0.0", 8080)

puts "Listening on http://0.0.0.0:8080"

server.listen

</syntaxhighlight>

===Type InferenceTCP andecho Unionserver Types===

<syntaxhighlight lang="crystal">

require "socket"

def handle_client(client)

message = client.gets

client.puts message

end

server = TCPServer.new("localhost", 1234)

while client = server.accept?

spawn handle_client(client)

end

</syntaxhighlight>

=== Type inference and union types ===

The following code defines an array containing different types with no usable common ancestor. Crystal automatically creates a union type out of the types of the individual items.

<syntaxhighlight lang="rubycrystal">

desired_things = [:unicorns, "butterflies", 1_000_000]

p typeof(desired_things.first) # typeof returns the compile time type, here (Int32Symbol | String | SymbolInt32)

p desired_things.first.class # the class method returns the runtime type, here Symbol

</syntaxhighlight>

=== Concurrency ===

Channels can be used to communicate between fibers, which are initiated using the keyword <code>spawn</code>.

<syntaxhighlight lang="crystal">

Channels can be used to communicate between fibers, which are initiated using the 'spawn' keyword.

<syntaxhighlight lang="ruby">

channel = Channel(Int32).new

Line 100 ⟶ 114:

</syntaxhighlight>

==References Adoption ==

In 2020, it was reported that the infotainment units in vehicles produced by [[Nikola Corporation]] were written in Crystal.<ref>{{cite web |last1=Pettinati |first1=Martin |title=Nikola Motor Company: Crystal powered dashboards on the trucks of the future {{!}} Manas.Tech |url=https://manas.tech/blog/2020/02/11/nikola-motor-company/ |website=Manas Technology Solutions |language=en |date=11 February 2020}}</ref> Much of the backend of the [[Kagi (search engine)|Kagi search engine]] is written with Crystal.<ref>{{cite web |title=Zac Nowicki – Tales from Kagi {{!}} CrystalConf 2023 |url=https://www.youtube.com/watch?v=r7t9xPajjTM |date=13 November 2023}}</ref>

== Further reading ==

{{Refbegin}}

* {{citation

| first1 = Simon

| last1 = St. Laurent

| first2 = Ivo

| last2 = Balbaert

| date = February 1, 2019

| title = Programming Crystal

| edition = P1.0

| publisher = [[Pragmatic Bookshelf]]

| isbn = 978-1-68050-286-2

| url = https://pragprog.com/book/crystal/programming-crystal

}}

* {{citation

| first1 = George

| last1 = Dietrich

| first2 = Guilherme

| last2 = Bernal

| date = May 27, 2022

| title = Crystal Programming

| publisher = [[Packt Publishing]]

| isbn = 978-1801818674

}}

* {{citation

| first1 = Ramon

| last1 = Wartala

| date = March 2016

| title = Die Ruby-artige Programmiersprache Crystal

| trans-title = The Ruby-like programming language Crystal

| work = [[Linux Magazine|Linux Magazin]]

| issue = 3/2016

| issn = 1432-640X

| language = de

| url = https://www.linux-magazin.de/ausgaben/2016/03/crystal/

}}

{{Refend}}

== References ==

{{Reflist|refs=

<ref name="platform-support">

{{cite web

| url = https://crystal-lang.org/reference/platform_support.html

| title = Crystal Platform Support

| website = crystal-lang.org

}}

</ref>

<ref name="contributors">

{{cite web

| url = https://github.com/crystal-lang/crystal/graphs/contributors

| title = Contributors

| accessdate=July 25, 2019

| via = [[GitHub]]

}}

</ref>

<ref name="type-inference-i">

{{cite web

| url = http://crystal-lang.org/2013/09/23/type-inference-part-1.html

| title = Type inference part 1

| last = Brian J.

| first = Cardiff

| date = September 9, 2013

| website = crystal-lang.org

}}

</ref>

<ref name="goodbye_ruby">

{{cite web

Line 108 ⟶ 189:

| last = Borenszweig

| first = Ary

| date = November 14, 2013

| website = crystal-lang.org

}}

</ref>

Line 116 ⟶ 199:

| last = Borenszweig

| first = Ary

| date = June 19, 2014

| website = crystal-lang.org

}}

</ref>

<ref name="why_crystal">

{{cite web

| url = httphttps://motion-expressadlerhsieh.com/blogp/why-use-crystal-lang

| title = Why Crystal programming language?

| last = Hsieh

| first = Adler

| date = September 20, 2015

| website = adlerhsieh.com

}}

</ref>

<ref name="story">

{{cite web

| url = httphttps://manas.com.artech/blog/2016/04/01/the-story-behind-crystal.html/

| title = The story behind #CrystalLang

| last = David

| first = María Inti

| date = April 1, 2016

| website = manas.tech

}}

</ref>

Line 140 ⟶ 229:

| last = Borenszweig

| first = Ary

| date = June 16, 2016

| quote = It's heavily inspired by Ruby, and other languages (like C#, Go and Python).

| website = crystal-lang.org

| quote =

}}

</ref>

<ref name="devm">

{{cite web

| url = https://devm.io/ruby/crystal-ruby-programming

| title = Programming with Crystal: 'A language for humans and computers'

| date = July 3, 2023

| website = devm.io

}}

</ref>

}}

== External links ==

* [http://{{Official website|crystal-lang.org/ Crystal official site]}}

* [https://githubcrystal-lang.comorg/manastechreference/crystal Crystal source codeDocumentation]

* {{Github|crystal-lang}}

* [https://reddit.com/r/crystal_programming /r/crystal_programming subreddit]

* [https://crystal-ann.com Crystal Announcements]

[[Category:Programming languages]]

[[Category:Multi-paradigm programming languages]]

[[Category:Object-oriented programming languages]]

[[Category:Concurrent programming languages]]

[[Category:Statically typed programming languages]]

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[[Category:Cross-platform software]]

[[Category:Free and open source compilers]]

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