Execute Brain****/Python

Implementation of a Brainfuck interpreter in Python.

Execute Brain****/Python is an implementation of Brainf***. Other implementations of Brainf***.

Execute Brain****/Python is part of RCBF. You may find other members of RCBF at Category:RCBF.

<lang python>#!/usr/bin/python import sys import collections

1. from collections import defaultdict instead since this only uses defaultdict?

def brainfuck (fd=None):

   fd = fd or (open(sys.argv[1]) if sys.argv[1:] else sys.stdin)
   source = fd.read()
   loop_ptrs = {}
   loop_stack = []
   for ptr, opcode in enumerate(source):
       if opcode == '[': loop_stack.append(ptr)
       if opcode == ']':
           if not loop_stack:
               source = source[:ptr]
               break
           sptr = loop_stack.pop()
           loop_ptrs[ptr], loop_ptrs[sptr] = sptr, ptr
   if loop_stack:
       raise SyntaxError ("unclosed loops at {}".format(loop_stack))
   tape = collections.defaultdict(int)
   cell = 0
   ptr = 0
   while ptr < len(source):
       opcode = source[ptr]
       if   opcode == '>': cell += 1
       elif opcode == '<': cell -= 1
       elif opcode == '+': tape[cell] += 1
       elif opcode == '-': tape[cell] -= 1
       elif opcode == ',': tape[cell] = ord(sys.stdin.read(1))
       elif opcode == '.': sys.stdout.write(chr(tape[cell]))
       elif (opcode == '[' and not tape[cell]) or \
            (opcode == ']' and tape[cell]): ptr = loop_ptrs[ptr]
       ptr += 1

if __name__ == "__main__": brainfuck()</lang>