fuckery.vm module

pyFuckery - vm.py Created on 2/12/17.

VM Definition to execute brainfuck programs which have been parsed into lark.Tree objects.

class fuckery.vm.VirtualMachine(memory_size: int = 30000, loop_detection: bool = False)

Bases: object

This is the brainfuck VM. You can drop this into programs that need a brainfuck VM, such as a module you don’t want a coworker to ever easily maintain, or a really cruel programming based game.

Init function for the VM.

Parameters:

• memory_size – Number of memory cells to instantiate.
• loop_detection – Enables loop detection if this evaluates to True. This is very costly from a

computation perspective, so use it wisely.

current_value

Property which represents the data value the current memory address points too.

Returns:

dec_data_ptr() → None

Decrements the data pointer by 1.

Returns:None

dec_data_value() → None

Decrements the value pointed to by the data pointer by 1. This wraps at zero, back to 255.

Returns:None

inc_data_ptr() → None

Increments the data pointer by 1.

Returns:None

inc_data_value() → None

Increments the value pointed to by the data pointer by 1. This wraps at 255, back to zero.

Returns:None

io_input() → None

Reads a single character from self.stream_in.

If self.stream_in is sys.stdin (default value), it will prompt the user for a string and record the FIRST byte of that string. Otherwise, it will attempt to read 1 byte from the stream_in buffer.

Empty inputs have no effect on the state of the system.

Returns:None

io_output() → None

Writes the current value, after casting it via chr(), to self.stream_out.

Returns:None

parse_and_run(program: str) → None

Parse and run a brainfuck program.

Parameters:program – String representing a brainfuck program. Returns:None

run(tree: lark.tree.Tree) → None

Walk a Brainfuck AST and execute the program contained in the AST.

This function is recursive, so its possible for a deeply nested program to hit the Python interpreter recursion limit, but if your brainfuck does that, kudos to you.

Parameters:tree – Parsed brainfuck program. Returns:

state_hash

MD5 representing the state of the system. It is a hash of the memory and the current data pointer.

Note - Computing this frequently can be expensive to do with a large memory section, as the memory section is serialized via msgpack.dumps() prior to hashing.

Returns:

fuckery.vm.main(options)

fuckery.vm.makeargpaser()