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Esoteric programming language - Wikiwand

Befunge

Befunge allows the instruction pointer to roam in multiple dimensions through the code. For example, the following program displays "Hello World" by pushing the characters in reverse order onto the stack, then printing the characters in a loop which circulates clockwise through the instructions >, :, v, _, ,, and ^.

There are many versions of Befunge, the most common being Befunge-93, named as such because of its release year.^[11]

Binary lambda calculus

Binary lambda calculus is designed from an algorithmic information theory perspective to allow for the densest possible code with the most minimal means, featuring a 29-byte self interpreter, a 21-byte prime number sieve, and a 112-byte Brainfuck interpreter.^[12]

Brainfuck

Brainfuck is designed for extreme minimalism and leads to obfuscated code, with programs containing only eight distinct characters. The following program outputs "Hello, world!":^[13]

++++++++++[>+++++++>++++++++++>+++<<<-]>++.>+.+++++++
 ..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.

All characters other than +-<>,.[] are ignored.

Chicken

Chicken has just three tokens, the word "chicken", " " (the space character), and the newline character. The compiler interprets the number of "chickens" on a line as an opcode instruction which it uses to manipulate data on a stack. A simple chicken program can contain dozens of lines with nothing but the word "chicken" repeated countless times.^[14] Chicken was invented by Torbjörn Söderstedt who drew his inspiration for the language from a parody of a scientific dissertation.^[15]^[16]^[17]

Chef

Chef is a stack-oriented programming language created by David Morgan-Mar, designed to make programs look like cooking recipes.^[18] Programs consist of a title, a list of variables and their data values, and a list of stack manipulation instructions.^[19] A joking design principle states that "program recipes should not only generate valid output, but be easy to prepare and delicious", and Morgan-Mar notes that an example "Hello, World!" program with 101 eggs and 111 cups (~26,640 mL) oil would produce "a lot of food for one person."^[19]^[20]

FRACTRAN

A FRACTRAN program is an ordered list of positive fractions together with an initial positive integer input $n$ . The program is run by multiplying the integer $n$ by the first fraction $f$ in the list for which $nf$ is an integer. The integer $n$ is then replaced by $nf$ and the rule is repeated. If no fraction in the list produces an integer when multiplied by $n$ , the program halts. FRACTRAN was invented by mathematician John Conway.^[21]

GolfScript

Programs in GolfScript, a language created for code golf, consist of lists of items, each of which is pushed onto the stack as it is encountered, with the exception of variables which have code blocks as their value, in which case the code is executed.^[22]

INTERCAL

INTERCAL, short for "Compiler Language With No Pronounceable Acronym", was created in 1972 as a parody to satirize aspects of the various programming languages at the time.^[4]

JSFuck

JSFuck is an esoteric programming style of JavaScript, where code is written using only six characters: [, ], (, ), !, and +. Unlike Brainfuck, which requires its own compiler or interpreter, JSFuck is valid JavaScript code, meaning JSFuck programs can be run in any web browser or engine that interprets JavaScript.^[23]^[24] It has been used in a number of cross-site scripting (XSS) attacks on websites such as eBay due to its ability to evade cross-site scripting detection filters.^[25]

LOLCODE

LOLCODE is designed to resemble the speech of lolcats. The following is the "Hello World" example:

HAI
CAN HAS STDIO?
VISIBLE "HAI WORLD!"
KTHXBYE

While the semantics of LOLCODE is not unusual, its syntax has been described as a linguistic phenomenon, representing an unusual example of informal speech and internet slang in programming.^[26]

Malbolge

Malbolge (named after the 8th circle of Hell) was designed to be the most difficult and esoteric programming language. Among other features, code is self-modifying by design and the effect of an instruction depends on its address in memory.^[27]

Piet

Piet is a language designed by David Morgan-Mar, whose programs are bitmaps that look like abstract art.^[28] The execution is guided by a "pointer" that moves around the image, from one continuous coloured region to the next. Procedures are carried out when the pointer exits a region.

There are 20 colours for which behaviour is specified: 18 "colourful" colours, which are ordered by a 6-step hue cycle and a 3-step brightness cycle; and black and white, which are not ordered. When exiting a "colourful" colour and entering another one, the performed procedure is determined by the number of steps of change in hue and brightness. Black cannot be entered; when the pointer tries to enter a black region, the rules of choosing the next block are changed instead. If all possible rules are tried, the program terminates. Regions outside the borders of the image are also treated as black. White does not perform operations, but allows the pointer to "pass through". The behaviour of colours other than the 20 specified is left to the compiler or interpreter.^[28]^{[non-primary source needed]}

Variables are stored in memory as signed integers in a single stack. Most specified procedures deal with operations on that stack, while others deal with input/output and with the rules by which the compilation pointer moves.^[29]

Piet was named after the Dutch painter Piet Mondrian.^[30] The original intended name, Mondrian, was already taken by an open-source statistical data-visualization system.^[28]

Shakespeare

Shakespeare Programming Language (SPL) is designed to make programs look like Shakespearean plays. For example, the following statement declares a point in the program which can be reached via a GOTO-type statement:^{[citation needed]}

 Act I: Hamlet's insults and flattery.

Unlambda

Unlambda is a minimalist functional programming language based on SKI calculus, but combined with first-class continuations and imperative I/O (with input usually requiring the use of continuations).^[31]

Whitespace

Whitespace uses only whitespace characters (space, tab, and return), ignoring all other characters, which can therefore be used for comments. This is the reverse of many traditional languages, which do not distinguish between different whitespace characters, treating tab and space the same. It also allows Whitespace programs to be hidden in the source code of programs in languages like C.^{[citation needed]}