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Brainfuck by FERcsI

A simple, minimal brainfuck interpreter with debugging functionality. The brainfuck language was not perfectly specified by the original author, so different versions are circulating on the net. This version is compatible with the first implementation. It has the following variable properties:

  • cell type: 8 bit unsigned integer initialized to 0
  • data pointer: no negative values allowed, initialized to 0
  • cell array size: 30.000
  • input stream: stdin or file
  • output stream: stdout

Requirements

  • No special prescription on OS, but I tested it only in Debian and Ubuntu Linux.
  • For compilation, you will need g++ with c++17 support. For more information, se configuration below.

Installation

Installation requires the following two simple instructions.

make
sudo make install

To run tests:

make test

Note that the interpreter is installed into the directory /usr/local/bin/, so if you would like to use shebang, you have to start your brainfuck script as follows:

#!/usr/local/bin/brainfuck

++++++[->++++++<].

Debugging

For debugging there are some features:

  • Commenting unnecessary code sniplets
  • Dumping a part of the cell array
  • Immediate exit

To turn on debugging mode, call brainfuck with option -d (or --debug). You can add that to the shebang, too.

#!/usr/local/bin/brainfuck -d

++++++[->++++++<]@.

Comments

In debug mode, comments start with # and end with the new line (LF, 0x0a) character. brainfuck instructions in comments are eliminated. So the following code prints a $ in debug mode and a # if debug mode is off.

++++++[->++++++<] #-
.

Memory Dump

With the additional instruction @ the content of the first N cells can be printed (to stderr):

[ 00 23 35 2f c1 00 01... ]

The number of cells to print can be given with the option -s (or --dump-size). The default is 32.

Also here the current cell is highlighted.

Immediate exit

With the additional instruction $ the interpreter stops processing the commands and exits with message to stderr:

[exit]

Configuration

Currently, I do not plan to change this project to be configurable, but later, who knows.

However, if you would like to change some parameters:

  • Cell array size: In brainfuck.cpp, change the value of CELL_ARRAY_SIZE.
  • Negative direction: Double the array size and set START_CELL_POS in the middle of the array.
  • Cell type: Change the type of CellType. Note that using signed integers instead of unsigned, doesn't make any difference.
  • Default dump size: Change DEFAULT_DUMP_SIZE

And the installation option:

  • Compiler: If you would like to use a different compiler, simply use it instead of running make. This is a single-file project and it does not need any special sources
  • Installation directory: Simply copy brainfuck to the desired directory after running make.

Using vim syntax file

If you are using vim, you can Copy the files in vim directory into your vim config environment ($HOME/.vim/, /usr/share/vim/addons/...).