This project is an extremely powerful, fast and memory safe interpreter for the iconic language 'brainfuck'.
The entire language is written using only 8 characters - <>[]+-,.
Note that there are a few more operators that have been (or are being) worked on as a sort of extension to brainfuck (think of it as bf++ :D).
Brainfuck programs consist of a large array being zero-initialised in memory, along with a pointer to the first element of the array. The values stored in the array are all unsigned integers (usize), and by default the array's size is 30,000 elements. Each of the 8 characters performs a single operation on the array. The operations are as follows [Source] -
Original -
> = increases array pointer, or moves the pointer to the right 1 block.
< = decreases array pointer, or moves the pointer to the left 1 block.
+ = increases value stored at the block pointed to by the array pointer.
- = decreases value stored at the block pointed to by the array pointer.
[ = like c while(current_block_value != 0) loop.
] = if value stored at block currently pointed to by the array pointer is not zero, jump back to [. else continue to the next operation.
, = like c getchar(). input 1 character and store its ASCII value in the block currently pointed to by the array pointer.
. = like c putchar(). print the character indicated by the ASCII encoding of the value in the current block.Additions -
^ - Prints 3 blocks around and including current pointer location (see end of doc for more).Any other characters apart from these 8 are ignored and treated as comments in the original language implementation.
Compile the interpreter on your own by cloning this repository and running the folllowing command -
cargo build --release
You will find your compiled executable somewhere in the directory target/release.
You can also install the package (build release and copy to path) using the following command -
cargo install --path .
After this, you should be able to run rs-brainfuck.exe (or rs-brainfuck if you're not on Windows) given that Cargo's bin path is in $PATH.
There are three command line options that can modify the behaviour of the program.
| Short Option | Long Option | Expects | Effect |
|---|---|---|---|
| <N.A.> | --arrlen | usize (unsigned integer) | Changes the size of the internal array. 30,000 by default. |
| -f | --file | String (file path) | Interprets file provided, if not provided interpreter will run in REPL mode. |
| -t | --time | bool (just put the flag) | Shows time taken for each step of execution. |
There are 2 modes the interpreter can run in, file mode or REPL mode.
The time option will print time after each line in REPL mode.
All errors reported by the interpreter are descriptive and self explanatory.
If the interpreter encounters an error in file mode, execution will stop the moment the error is caught and program will quit.
Errors caught in REPL mode will not cause the program to close, type "exit", "quit" or "q" in REPL mode to exit safely.
Using chumsky for parsing
This will allow for better error messages and shorter, more readable code.
The operator will print the current status of the program similar to this -
Internal Array (capacity: 30,000)
[ ... [123] [512] [215] ...]
^
ptr = 6
This feature will autoexecute in the REPL.
Passing in a flag -t will report the time taken for each process - Lexing, Parsing, Interpreting
Eg -
[INFO] : Lexed tokens in 0.61 seconds.
[INFO] : Parsed instructions in 0.09 seconds.
[INFO] : Interpreted instructions in 2.1 seconds.
[OK] : Execution completed sucessfully.