Icon

Icon is a programming language created in 1977 by Ralph Griswold.

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Try now: Riju · TIO

Icon is a very high-level programming language featuring goal-directed execution and many facilities for managing strings and textual patterns. It is related to SNOBOL and SL5, string processing languages. Icon is not object-oriented, but an object-oriented extension called Idol was developed in 1996 which eventually became Unicon.. Read more on Wikipedia...

Icon website
Icon Wikipedia page
Icon docs
Icon first developed in The University of Arizona
file extensions for Icon include icon and ICON
Explore Icon snippets on Rosetta Code
Icon on HOPL
Icon appears in the TIOBE Index
Icon Ubuntu package
Pygments supports syntax highlighting for Icon
Icon appears in the Quine Relay project
See also: (9 related languages)SNOBOL, Algol, Python, Unicon, C, Pascal, Java, Smalltalk, CLU
HTML of this page generated by LanguagePage.ts

Example from Riju:

procedure main ()
    write("Hello, world!")
end

Example from hello-world:

procedure main()
    write("Hello World");
end

Example from the Hello World Collection:

# Hello world in Icon (http://www.cs.arizona.edu/icon/)

procedure main()
    write("Hello world")
end

Example from Wikipedia:

procedure main()
     s := "Mon Dec 8"
     s ? write(Mdate() | "not a valid date")
 end
 # Define a matching function that returns
 # a string that matches a day month dayofmonth
 procedure Mdate()
 # Define some initial values
 static dates
 static days
 initial {
        days := ["Mon","Tue","Wed","Thr","Fri","Sat","Sun"]
        dates := ["Jan","Feb","Mar","Apr","May","Jun",
                  "Jul","Aug","Sep","Oct","Nov","Dec"]
 }
 every suspend   (retval <-  tab(match(!days)) ||     # Match a day
                             =" " ||                  # Followed by a blank
                             tab(match(!dates)) ||    # Followed by the month
                             =" " ||                  # Followed by a blank
                             matchdigits(2)           # Followed by at least 2 digits
                 ) &
                 (=" " | pos(0) ) &                   # Either a blank or the end of the string
                 retval                               # And finally return the string
 end
 # Matching function that returns a string of n digits
 procedure matchdigits(n)
     suspend (v := tab(many(&digits)) & *v <= n) & v
 end

Feature	Supported	Token	Example
Integers	✓		# \b([+-]?[0-9]+[KMGTPkmgtp]?)\b
Floats	✓		# [+-]?[0-9]\.([0-9])([Ee][+-]?[0-9]*)?
Hexadecimals	✓		# \b([+-]?([2-9]\|[12][0-9]\|3[0-6])[rR][0-9a-zA-Z]+)\b
Strings	✓	"	"Hello world"
Print() Debugging	✓	write
Comments	✓		# A comment
Line Comments	✓	#	# A comment
Semantic Indentation	X

Feature

Supported

Token

Example

Integers

✓

# \b([+-]?[0-9]+[KMGTPkmgtp]?)\b

Floats

✓

# [+-]?[0-9]*\.([0-9]*)([Ee][+-]?[0-9]*)?

Hexadecimals

✓

# \b([+-]?([2-9]|[12][0-9]|3[0-6])[rR][0-9a-zA-Z]+)\b

Strings

✓

"Hello world"

Print() Debugging

✓

write

Comments

✓

# A comment

Line Comments

✓

# A comment

Semantic Indentation

title	authors	year	publisher
The Icon Book: Visual Symbols for Computer Systems and Documentation	Horton, William	1994	Wiley
Graphics Programming In Icon	Ralph E. Griswold and Gregg M. Townsend and Clinton L. Jeffery	1998	Peer To Peer Communications
The Icon Programming Language (prentice-hall Software Series)	Ralph E Griswold	1983	Prentice-hall

title

authors

year

publisher

The Icon Book: Visual Symbols for Computer Systems and Documentation

Horton, William

1994

Wiley

Graphics Programming In Icon

Ralph E. Griswold and Gregg M. Townsend and Clinton L. Jeffery

1998

Peer To Peer Communications

The Icon Programming Language (prentice-hall Software Series)

Ralph E Griswold

1983

Prentice-hall

title	authors	year	citations	influentialCitations
Generators in Icon	R. Griswold and D. R. Hanson and John T. Korb	1981	52	2
A portable storage management system for the icon programming language	D. R. Hanson	1980	27	3
The icon programming language: an overview	R. Griswold and D. R. Hanson and John T. Korb	1979	21	1
Measuring the Performance and Behavior of Icon Programs	Cary A. Coutant and R. Griswold and D. R. Hanson	1983	20	0
The Evaluation of Expressions in Icon	R. Griswold	1982	15	1
A framework for execution monitoring in icon	C. Jeffery and R. Griswold	1994	13	2
The implementation of generators and goal‐directed evaluation in icon	S. Wampler and R. Griswold	1983	11	0
String Scanning in the Icon Programming Language	R. Griswold	1990	11	0
An optimizing compiler for the icon programming language	Kenneth Walker and R. Griswold	1992	11	1
History of the Icon programming language	R. Griswold and Madge T. Griswold	1993	10	0
A recursive interpreter for the Icon programming language	Janalee O'Bagy and R. Griswold	1987	10	0
The design and implementation of dynamic hashing for sets and tables in icon	W. Griswold and Gregg M. Townsend	1993	9	1
A new implementation of the Icon language	T. Proebsting and Gregg M. Townsend	2000	9	1
Co-Expressions in Icon	S. Wampler and R. Griswold	1983	6	0
Logicon: An integration of prolog into icon	G. Lapalme and S. Chapleau	1986	6	1
Expression evaluation in the icon programming language	R. Griswold	1984	5	0
Modeling software tools with ICON	O. Fonorow	1988	4	0
The Icon programming language a new approach to high-level string processing	R. Griswold	1979	2	0
Garbage collection alternatives for icon	M. Fernández and D. R. Hanson	1992	1	1

title

authors

year

citations

influentialCitations

Generators in Icon

R. Griswold and D. R. Hanson and John T. Korb

1981

A portable storage management system for the icon programming language

D. R. Hanson

1980

The icon programming language: an overview