Tiny Brainf**k interpreter in under 70 lines of portable C99 code.
Brainf**k is an extremely minimalistic esoteric programming language designed by Urban Müller in 1993. It is notorious for being difficult to both read and write despite being very simple. It is also a Turing-complete language, meaning it can be used to, simply speaking, perform any possible computation.
A Brainf**k program is an ordered sequence of commands, each encoded by a single character. The commands can read and write memory from an array of at least 30,000 byte cells initially set to zero, but only one cell at a time. The cell which the program can currently access is controlled by the data pointer, and the command being executed is set by the instruction pointer. Basic I/O is performed through the data pointer, and the execution flow can be controlled using only conditional jumps of the instruction pointer.
Altogether, the language itself consists of only eight commands:
| Character | Description |
|---|---|
> |
Increment the data pointer (i.e., move to the cell to the right). |
< |
Decrement the data pointer (i.e., move to the cell to the left). |
+ |
Increment the byte at the data pointer. |
- |
Decrement the byte at the data pointer. |
. |
Output the byte at the data pointer. |
, |
Accept one byte of input, storing its value at the data pointer. |
[ |
If the byte at the data pointer is zero, jump forward to the command after the matching ]. |
] |
If the byte at the data pointer is non-zero, jump backward to the command after the matching [. |
There isn't much use for a yet another Brainf**k interpreter as the language itself was deliberately designed to be entirely pointless. I only made this implementation for a little fun in under an hour while configuring my development environment. The interpreter is compliant with the language specification and can execute even complex programs, but it is intentionally simplistic and naïve, as is evident by the lack of error handling and memory safety. I aimed at making a succinct and (subjectively) elegant implementation, and I'm quite satisfied with the result. Maybe you will find this pleasing, too!
The mandelbrot.bf program contains a copy of the Mandelbrot set viewer created by Erik Bosman, and is broadly considered to be one of the most challenging programs to execute for a Brainf**k interpreter. Below, you may find a screenshot of the program's output produced by Brainheck. The interpreter was also tested against various other sample programs which may be found online, including Sierpinski triangles, a playable Tic-Tac-Toe, and even a universal Turing machine simulator.
MIT, Copyright © 2021, Daniils Buts