tleguern / kbf

kbf - the Korn shell BrainFuck interpreter

kbf

The Korn shell BrainFuck interpreter

Contents

1. Synopsis
2. Install
3. Tests
4. Contributing
5. License

Synopsis

kbf [-dsD] [-c size] [-o optimisation] [-t size] [-O level] file[.b]

kbf is a brainfuck interpreter written in korn shell. It is currently compatible with multiple shells, not just bash, and thus is probably the most portable implementation. The following shells are supported:

• Public Domain Korn SHell - pdksh;
• OpenBSD Korn SHell - oksh;
• MirBSD Korn SHell - mksh;
• GNU Bourne-Again SHell - bash;
• The Z shell - zsh.

Other shells might be supported in the future in they handle extension to POSIX such as local variables and arrays. This implementation works with various cell sizes from 8 to 64 bits but default to 24 as it is the largest size handled by all supported shells.

Through the switches -O and -o it is possible to enable some optimisation strategies, such as optimised operators for some simple constructions and run length encoding.

The “bitwidth.b” torture test written by rdebath works at every cell sizes and optimisation levels :

cell size	Output
8	Hello World! 255
16	Hello world! 65535
24	Hello, world!
32s	Hello, world!
32u	Hello, world!
64s	Hello, world!

kbf can be used directly or as a library. The later can be useful to extend the brainfuck language or implement variants such as Ook! and blub (as implemented in the examples directory). The usage and behaviour of this mode is described in the man page kbf.3 while the executable command is described in kbf.1. It is possible to read them with either mandoc or groff:

$ mandoc kbf.1 | less
$ groff -m mdoc -Tascii kbf.1 | less

A mandoc version of these man pages is also provided: kbf.1.md and kbf.3.md.

Install

Requires

• Any a-bit-more-than-POSIX shell.

Build

There is a makefile available for BSD systems, just run make install. If you use something else just use cp kbf.sh $DESTDIR/kbf.

Tests

Regression tests are available and documented in a dedicated regress/README.md.

Contributing

Either send send GitHub pull requests or send patches on SourceHut.

License

All the code is licensed under the ISC License.