bff (which stands for Befunge Forever) is a toy project of mine, the secondary purpose of which is to interpret Befunge 93 (and soon 98) progams.
Its primary purpose is learning Rust.
Befunge 93 is an awesome esoteric stack-based programming language, where the program is not a sequence but a grid of instructions, like the following program that reads an integer from stdin and prints its factorial:
befunge
&>:1-:v v *_$.@
^ _$>\:^
The program counter / instruction pointer starts from the top left corner and moves around the grid, executing instructions and changing directions,
until it meets the @ instruction, terminating the execution of the program.
You can read more about Befunge 93 here.
Befunge 98 is a turing-complete extension of Befunge 93. Tt expands the program grid infinitely (Befunge 93 limits it to 80x25), adds file I/O operations, support for libraries (which it calls "fingerprints"), and much much more.
You can read more about Befunge 98 here.
bff is under heavy development (in the dev branch). It considers itself to be a working Befunge 93 interpreter, though
(thanks to the Mycology testsuite for some of the tests).
The main future goal is to expand bff to be a fully fledged Befunge 98 interpreter, backwards compatible with Befunge 93.
Any comments/remarks/criticism in the form of issues are welcome.
Any contributions in the form of pull requests are welcome, if they are properly documented and accompanied by tests.
Because I believe that writing a quirky interpreter is one of the best ways to learn a systems, memory safe, type strict programming language like Rust.
To use bff, you have 2 options:
$ cd bff
$ cargo build --release
The bff executable will now be under the ./target/release/ directory.
crates.io:
$ cargo install bff
You can use bff as an executable, if you installed it via cargo:
$ cat hello_world.bf
"!dlrow olleH">:#,_@
$ bff hello_world.bf
Hello world!
Or, if you downloaded/cloned the repo:
$ cargo run -- tests/bf93/hello_world.bf
[...]
Hello world!