13 stable releases

1.2.1 May 27, 2021
1.2.0 May 22, 2021
1.1.4 Apr 29, 2021

#672 in Parser implementations

43 downloads per month

Apache-2.0 and LGPL-3.0+



Build Status

A general-purpose functional golfing language. Tutorial


Post 1.0

First, ensure Rust is installed on your system and that these requirements are fulfilled. You can either build from source by cloning the repository and then running

cargo install --path path/to/repository

for the latest features, or by simply running

cargo install arn-language

for the current release edition. You then can run

arn --help

to get a list of commands.

Prior to 1.0

To install Arn you must have Node.js installed on your system. Once installed, run

npm install -g arn-language

You can then use

arn help

to get a list of commands


Arn is a golfing language; that is, it is designed to perform tasks in as few bytes as possible. It draws heavy inspiration from J/APL

Arn is constructed of variable declarations, functions, and symbols. These symbols come in the forms of prefixes, infixes, and suffixes. A full syntax and description can be found at this page. This format, however, may lead to instances where your program needs to be a few bytes shorter in order to compete. This is where Carn (Compressed Arn) comes in.


Carn is the compressed version of Arn. The interpeter has the ability to distinguish between these two program formats and interpret each separately, without any input from the user. Carn is encoded using its own Code Page, based on CP1252. It can be found below. The Arn interpreter will compress your program by passing in the -c flag to the compiler through the command line.

Code Page

_ _0 _1 _2 _3 _4 _5 _6 _7 _8 _9 _A _B _C _D _E _F
0_ ! " # $ % & ' ( ) * + , - . / 0
1_ 1 2 3 4 5 6 7 8 9 : ; < = > ? @
2_ A B C D E F G H I J K L M N O P
3_ Q R S T U V W X Y Z [ \ ] ^ _ `
4_ a b c d e f g h i j k l m n o p
5_ q r s t u v w x y z { | } ~ ¡ ¢
6_ £ ¤ ¥ ¦ § ¨ © ª « ¬ ® ¯ °
8_ ± ² ³
9_ ´ µ · ¸ ¹ º » ¼ ½ ¾ ¿ À Á Â Ã
A_ Ä Å Æ Ç È É Ê Ë Ì Í Î Ï Ð Ñ Ò Ó
B_ Ô Õ Ö × Ø Ù Ú Û Ü Ý Þ ß à á â ã
C_ ä å æ ç è é ê ë ì í î ï ð ñ ò ó
D_ ô õ ö ÷ ø ù ú û ü ý þ ÿ Œ œ Š š
E_ Ÿ Ž ž ƒ ƥ ʠ ˆ ˜
F_ Δ

Some sample programs

Hello, World

'yt, bs!

Cat program


FizzBuzz (1->100)


Fibonacci Sequence

[1 1{+

Prime Check


Uses Wilson's Theorem


Future Plans

I plan on working on more practical features in the future, and I'm also going to look into changing the way certain operations work on sequences, among other things.


~452K SLoC