Editing Io (programming language) (section)

{{Short description|Prototype-based programming language}}
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{{Infobox programming language
| name = Io
| logo = Io-logo.svg
| logo_size = 150px
| paradigms = [[Object-oriented programming|object-oriented]] [[Prototype-based programming|prototype-based]]
| designer = Steve Dekorte
| developers = Steve Dekorte, Jonathan Wright, Jeremy Tregunna
| released = {{Start date and age|2002}}
| latest release version = 20170906
| latest release date = {{Start date and age|2017|09|06}}<ref name="Releases">{{cite web |url=https://github.com/IoLanguage/io/releases |title=Io Releases |website=[[GitHub]] |access-date=2020-02-06}}</ref>
| latest preview version = 2019.05.22-alpha
| latest preview date = {{Start date and age|2019|05|22}}
| typing = [[Type system|dynamic]], [[Strong and weak typing|strong]]
| platform = [[IA-32]], [[x86-64]]; [[ARM architecture family|ARM]]; [[.NET]] [[Common Language Runtime|CLR]]
| operating system = [[Microsoft Windows|Windows]], [[macOS]]
| license = [[BSD licenses|BSD 3-clause]]
| implementations = [http://iolanguage.org/ Io] [https://web.archive.org/web/20110716175739/http://synrc.com/io/index.htm Io.NET]
| influenced by = [[Smalltalk]], [[NewtonScript]], [[Self (programming language)|Self]], [[Lua (programming language)|Lua]], [[Lisp (programming language)|Lisp]], [[Python (programming language)|Python]], [[Actor model middle history#Actor programming languages|Act1]]
| influenced = Ioke, Potion
}}

'''Io''' is a pure [[object-oriented programming]] [[Programming language|language]] inspired by [[Smalltalk]], [[Self (programming language)|Self]], [[Lua (programming language)|Lua]], [[Lisp (programming language)|Lisp]], [[Actor model middle history#Actor programming languages|Act1]], and [[NewtonScript]].<ref>[http://iolanguage.org/guide/guide.html#Introduction-Overview Io Programming Guide]</ref> Io has a [[Prototype-based programming|prototype-based]] object model similar to those in Self and NewtonScript, eliminating the distinction between [[Object (computer science)|instance]] and [[Class (computer programming)|class]]. Like Smalltalk, everything is an object and it uses [[Type system|dynamic typing]]. Like Lisp, programs are just data trees. Io uses [[actor model|actor]]s for concurrency.

Remarkable features of Io are its minimal size and openness to using external code resources.<ref>{{Cite web |title=Io Programming: Writing Addons |url=https://en.wikibooks.org/wiki/Io_Programming/Writing_Addons |access-date=2023-06-22 |website=Wikibooks.org: open books for an open world |language=en}}</ref> Io is executed by a small, portable [[virtual machine]].