| Brainfuck | |
| File Ext: | .b, .bf |
| Paradigm: | Esoteric, imperative, structured |
| Released: | September 1993 |
| Designer: | Urban Müller |
| Typing: | Typeless |
| Influenced By: | P′′, FALSE |
| Influenced: | Malbolge |
Brainfuck is an esoteric programming language created in 1993 by Swiss physics student Urban Müller.[1] Designed to be extremely minimalistic, the language consists of only eight simple commands, a data pointer and an instruction pointer.[2]
Brainfuck is an example of a so-called Turing tarpit: it can be used to write any program, but it is not practical to do so, because it provides so little abstraction that the programs get very long or complicated. While Brainfuck is fully Turing complete, it is not intended for practical use, but to challenge and amuse programmers.[3] [4] Brainfuck requires one to break commands into microscopic steps.
The language takes its name from the slang term brainfuck, which refers to things so complicated or unusual that they exceed the limits of one's understanding, as it was not meant or made for designing actual software but to challenge the boundaries of computer programming.
Because the language's name contains profanity, many substitutes are used, such as brainfsck, branflakes, brainoof, brainfrick, BrainF, and BF.[5]
Müller designed Brainfuck with the goal of implementing the smallest possible compiler,[6] inspired by the 1024-byte compiler for the FALSE programming language.[7] Müller's original compiler was implemented in machine language and compiled to a binary with a size of 296 bytes. He uploaded the first Brainfuck compiler to Aminet in 1993. The program came with a "Readme" file, which briefly described the language, and challenged the reader "Who can program anything useful with it? :)". Müller also included an interpreter and some examples. A second version of the compiler used only 240 bytes.[8]
The language consists of eight commands. A brainfuck program is a sequence of these commands, possibly interspersed with other characters (which are ignored). The commands are executed sequentially, with some exceptions: an instruction pointer begins at the first command, and each command it points to is executed, after which it normally moves forward to the next command. The program terminates when the instruction pointer moves past the last command.
The brainfuck language uses a simple machine model consisting of the program and instruction pointer, as well as a one-dimensional array of at least 30,000 byte cells initialized to zero; a movable data pointer (initialized to point to the leftmost byte of the array); and two streams of bytes for input and output (most often connected to a keyboard and a monitor respectively, and using the ASCII character encoding).
The eight language commands each consist of a single character:
| Character | Meaning |
|---|---|
> | Increment the data pointer by one (to point to the next cell to the right). |
< | Decrement the data pointer by one (to point to the next cell to the left). |
+ | Increment the byte at the data pointer by one. |
- | Decrement the byte at the data pointer by one. |
. | Output the byte at the data pointer. |
, | Accept one byte of input, storing its value in the byte at the data pointer. |
[| If the byte at the data pointer is zero, then instead of moving the instruction pointer forward to the next command, jump it forward to the command after the matching ] command. | |
] | If the byte at the data pointer is nonzero, then instead of moving the instruction pointer forward to the next command, jump it back to the command after the matching [ command.|}
Brainfuck programs are usually difficult to comprehend. This is partly because any mildly complex task requires a long sequence of commands and partly because the program's text gives no direct indications of the program's state. These, as well as Brainfuck's inefficiency and its limited input/output capabilities, are some of the reasons it is not used for serious programming. Nonetheless, like any Turing complete language, Brainfuck is theoretically capable of computing any computable function or simulating any other computational model, if given access to an unlimited amount of memory.[9] A variety of Brainfuck programs have been written.[10] Although Brainfuck programs, especially complicated ones, are difficult to write, it is quite trivial to write an interpreter for Brainfuck in a more typical language such as C due to its simplicity. Brainfuck interpreters written in the Brainfuck language itself also exist.[11] [12] ExamplesAdding two valuesAs a first, simple example, the following code snippet will add the current cell's value to the next cell: Each time the loop is executed, the current cell is decremented, the data pointer moves to the right, that next cell is incremented, and the data pointer moves left again. This sequence is repeated until the starting cell is 0. This can be incorporated into a simple addition program as follows: [Start your loops with your cell pointer on the loop counter (c1 in our case) < + Add 1 to c0 > - Subtract 1 from c1 ] End your loops with the cell pointer on the loop counter At this point our program has added 5 to 2 leaving 7 in c0 and 0 in c1but we cannot output this value to the terminal since it is not ASCII encoded To display the ASCII character "7" we must add 48 to the value 7We use a loop to compute 48 = 6 * 8 ++++ ++++ c1 = 8 and this will be our loop counter again[< +++ +++ Add 6 to c0 > - Subtract 1 from c1 ]< . Print out c0 which has the value 55 which translates to "7"! Hello World!The following program prints "Hello World!" and a newline to the screen: This loop is an "initial comment loop", a simple way of adding a comment to a BF program such that you don't have to worry about any command characters. Any ".", ",", "+", "-", "<" and ">" characters are simply ignored, the "[" and "]" characters just have to be balanced. This loop and the commands it contains are ignored because the current cell defaults to a value of 0; the 0 value causes this loop to be skipped.]++++++++ Set Cell #0 to 8[>++++ Add 4 to Cell #1; this will always set Cell #1 to 4 [ as the cell will be cleared by the loop >++ Add 2 to Cell #2 >+++ Add 3 to Cell #3 >+++ Add 3 to Cell #4 >+ Add 1 to Cell #5 <<<<- Decrement the loop counter in Cell #1 ] Loop until Cell #1 is zero; number of iterations is 4 >+ Add 1 to Cell #2 >+ Add 1 to Cell #3 >- Subtract 1 from Cell #4 >>+ Add 1 to Cell #6 [<] Move back to the first zero cell you find; this will be Cell #1 which was cleared by the previous loop <- Decrement the loop Counter in Cell #0] Loop until Cell #0 is zero; number of iterations is 8 The result of this is:Cell no : 0 1 2 3 4 5 6Contents: 0 0 72 104 88 32 8Pointer : ^ >>. Cell #2 has value 72 which is 'H'>---. Subtract 3 from Cell #3 to get 101 which is 'e'+++++++..+++. Likewise for 'llo' from Cell #3>>. Cell #5 is 32 for the space<-. Subtract 1 from Cell #4 for 87 to give a 'W'<. Cell #3 was set to 'o' from the end of 'Hello'+++.------.--------. Cell #3 for 'rl' and 'd'>>+. Add 1 to Cell #5 gives us an exclamation point>++. And finally a newline from Cell #6 For readability, this code has been spread across many lines, and blanks and comments have been added. Brainfuck ignores all characters except the eight commands ROT13This program enciphers its input with the ROT13 cipher. To do this, it must map characters A-M (ASCII 65–77) to N-Z (78-90), and vice versa. Also it must map a-m (97-109) to n-z (110-122) and vice versa. It must map all other characters to themselves; it reads characters one at a time and outputs their enciphered equivalents until it reads an EOF (here assumed to be represented as either -1 or "no change"), at which point the program terminates. Simulation of abiogenesisIn 2024, a Google research project used Brainfuck as the basis of an artificial digital environment. In this environment, they found that replicators arose naturally and competed with each other for domination of the environment. 2024 . Computational Life: How Well-formed, Self-replicating Programs Emerge from Simple Interaction . 2406.19108 . cs.NE. Blaise Agüera y Arcas . Alakuijala . Jyrki . Evans . James . Laurie . Ben . Mordvintsev . Alexander . Niklasson . Eyvind . Randazzo . Ettore . Versari . Luca . See also
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