ultrabear/bfi

A commandline brainfuck interpreter written to balance execution speed and convenience

ultrabear/bfi

A commandline brainfuck interpreter written to balance execution speed and convenience

Basically

I had wanted a commandline tool to execute brainfuck inline with scripts, why did I want that? dunno but it stuck
The initial version of bfi was written in python, and then ported to golang where it got actual care to running fast
While the goal of bfi is to be scriptable and convenient to just boot up on the commandline, it also hopes to be fast enough to handle most brainfuck in a timely matter, with a static compiling stage that doesnt run any brainfuck code while trying to optimize it

Installation/Usage

Install

sudo make install

Install (no root)

make userinstall

Makefile flags:

GOCMD=go # What go binary to use, if you use go get'd go versions
EXE=bfi # Name of binary

Usage (argv)

bfi "++++[>++++[>++++<-]>>++<<<-]>>+.>++." # Prints A and a newline

Usage (files)

bfi f <filename>

This implementation

Notable Differences

• It will compress opposing instructions out of the loop entirely
  • What this means is that +- will be compiled to NIL and <> will be compiled to NIL
  • A special behaviour of this is that < will raise an error for underflowing the pointer location but <> will raise no error as before it gets to runtime that is compiled out
• The buffer size is calculated at compile time based off the count of > instructions or 30k as a minimum, for the brainfuck standard
  • In most cases this will not error on brainfuck, but some programs rely on buffer flying and may not function correctly
• [] is compiled out entirely
  • This was in a weak attempt to strip some comments from the program so that it does not affect runtime
  • Notably programs such as +[] will not loop forever and will instead just run as + on another interpreter
  • As [] is essentially an infinite loop this will not affect most programs

Other Notes

• The execution environment is 8 bit brainfuck, there are no settings to use other sizes

Credits

All example programs (except beemovie.bf) came from the example sets from El Brainfuck, a bf-to-JS compilier implementation with debugging tools and variable buffer widths
Some misleading wording in the implementation notes was pointed out by rdebath, thanks!