public/subjects/brainfuck

brainfuck

Esoteric programming languages (esolang) are designed to test the boundaries of computer programming design, as proofs of concept, as software art, as a hacking interface or simply as a joke. One such esoteric language is Brainfuck. It was created by Urban Müller in 1993. It is a minimalist language consisting of 8 simple commands. It is Turing complete, but is not intended for practical use. It exists to amuse and challenge programmers.

Instructions

Write a Brainfuck interpreter program.

The source code will be given as the first parameter, and will always be valid with fewer than 4096 operations.

Your Brainfuck interpreter will consist of an array of 2048 bytes, all initialized to 0, with a pointer to the first byte.

Every operator consists of a single character:

• >: increment the pointer.
• <: decrement the pointer.
• +: increment the pointed byte.
• -: decrement the pointed byte.
• .: print the pointed byte to the standard output.
• [: if the pointed byte is 0, then instead of moving onto the next command, skip to the command after the matching ].
• ]: if the pointed byte is not 0, then instead of moving onto the next command, move back to the command after the matching [.

Any other character is a comment.

Usage

$ go run . "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>." | cat -e
Hello World!$
$ go run . "+++++[>++++[>++++H>+++++i<<-]>>>++\n<<<<-]>>--------.>+++++.>." | cat -e
Hi$
$ go run . "++++++++++[>++++++++++>++++++++++>++++++++++<<<-]>---.>--.>-.>++++++++++." | cat -e
abc$
$ go run .
$