bfx

bfx

An extensible interpreter, compiler, and REPL for brainfuck-like languages

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Table of Contents

• Overview
• Building
• Usage
  • General Interpreter Options
  • Compiler options
  • Other options
  • Supported Languages
• Extending
• Screenshots
• Further Reading
• Bugs
• License

Overview

This is an interpreter, compiler, and REPL for the following Turing-complete esoteric programming languages:

• Brainfork
• Brainfuck
• Grin
• Pbrain
• Weave

Most tape-based single-character instruction languages can be incorporated into libbfx with relative ease (see Extending).

Building

Linux

cmake . -B build
cmake --build build
sudo cmake --install build

Usage

bfx [options...] [file]

General Interpreter Options

• -e eof_behavior: Specify behavior when encountering EOF. Valid values are "zero" (the default, sets the current cell to zero), "decrement" (subtract one from the current cell), and "unchanged" (do not change the current cell).
• -i: Separate code from input using ! (Note: Grin is not supported here).
• -l language: Specify the language to use (Default: brainfuck).
• -r: Run in interactive REPL mode (Note: Weave is not supported here).
• -t tape_size: Specify the size of the tape (default: 30000).

Compiler Options

Note that the bfx library must be installed to your PATH in order to use these options. Compiled code may be run without the bfx library.

• -c: Compile the given program to a native binary.
• -o output_file: Specify the output file (default: './a.out')

Other Options

• -D: Default to degrees instead of radians (Grin).
• -P precision: Specify the number of decimal places to print (Grin). Default is 4.
• -v: Print version information.

Languages

• brainfork
• brainfuck (Default)
• grin
• pbrain
• weave

If file is not specified, bfx will read source code from standard input.

Extending

It is possible to add support for new languages pretty easily by following these steps:

1. Create a new source and header file for the language in libbfx/src/langs.
2. Implement the language using the conventional init and run functions and operations array (see libbfx/src/langs/brainfuck.c and libbfx/src/langs/brainfuck.h).
3. Add the source file to libbfx/CMakeLists.txt.
4. Add the language to the BFX_Languages enum in libbfx/src/bfx.h.
5. Add a BFX_LANG(NAME) macro to the list in libbfx/src/interpret.c.
6. Update get_language() in bfx/src/main.c.

Screenshots

bfx running sierpinski.b

Further Reading

• Esolang Wiki
• brainfuck.org

Bugs

If you find a bug, submit an issue, PR, or email me with a description and/or patch.

License

Copyright (c) 2022-2026 Ben O'Neill ben@o.nosp@m.neil.nosp@m.l.sh. This work is released under the terms of the MIT License. See [LICENSE](LICENSE) for the license terms.