Io - Programming language

Io is a programming language created in 2002 by Steve Dekorte.

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Io is a pure object-oriented programming language inspired by Smalltalk, Self, Lua, Lisp, Act1, and NewtonScript. Io has a prototype-based object model similar to the ones in Self and NewtonScript, eliminating the distinction between instance and class. Like Smalltalk, everything is an object and it uses dynamic typing. Read more on Wikipedia...

Tags: programming language
There are at least 2,062 Io repos on GitHub
Early development of Io happened in https://github.com/IoLanguage
The Google BigQuery Public Dataset GitHub snapshot shows 594 users using Io in 624 repos on GitHub
Explore Io snippets on Rosetta Code
Io on HOPL
Pygments supports syntax highlighting for Io
GitHub supports syntax highlighting for Io
iolanguage.org was registered in 2009
See also: (7 related languages) Smalltalk, NewtonScript, Self, Lua, Lisp, Python, Ioke
Read more about Io on the web: 1.

Example from Riju:

"Hello, world!" println

Example from hello-world:

"Hello World\n" print

Example from Wikipedia:

factorial := method(n,
    if(n == 0, return 1)
    res := 1
    Range 1 to(n) foreach(i, res = res * i)
)

Language features

Feature	Supported	Example	Token
MultiLine Comments	✓
Integers	✓	// \d+
Floats	✓	// (\d+\.?\d\|\d\.\d+)([eE][+-]?[0-9]+)?
Assignment	✓		:=
Print() Debugging	✓		print
Line Comments	✓	// A comment	//
Operator Overloading	✓
Comments	✓
Semantic Indentation	X