Io (programming language)

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Io

Paradigms	object-oriented prototype-based
Designed by	Steve Dekorte
Developers	Steve Dekorte, Jonathan Wright, Jeremy Tregunna
First appeared	2002; 22 years ago (2002)
Stable release	20170906 / September 6, 2017; 6 years ago (2017-09-06)[1]
Preview release	2019.05.22-alpha / May 22, 2019; 5 years ago (2019-05-22)
Typing discipline	dynamic, strong
Platform	IA-32, x86-64; ARM, M1–M4; .NET CLR
OS	Windows, macOS
License	BSD 3-clause
Website	iolanguage.org
Major implementations
Io Io.NET
Influenced by
Smalltalk, NewtonScript, Self, Lua, Lisp, Python, Act1
Influenced
Ioke, Potion

Io is a pure object-oriented programming language inspired by Smalltalk, Self, Lua, Lisp, Act1, and NewtonScript.^[2] Io has a prototype-based object model similar to those in Self and NewtonScript, eliminating the distinction between instance and class. Like Smalltalk, everything is an object and it uses dynamic typing. Like Lisp, programs are just data trees. Io uses actors for concurrency.

Remarkable features of Io are its minimal size and openness to using external code resources.^[3] Io is executed by a small, portable virtual machine.