tape.py

import collections
import random

def randprog(length=12):
    return ''.join(random.choice('><+-[]') for i in range(length))

def execute(prog, tape):
    i = 0
    j = 0
    l = len(prog)
    total = 0
    ctrl = []
    jumps = {}
    tape[0]
    for k, x in enumerate(prog):
        if x == '[':
            ctrl.append(k)
        if x == ']':
            try:
                n = ctrl.pop()
            except:
                return -1
            jumps[k] = n
            jumps[n] = k
    if ctrl != []:
        return -1
    while j != l:
        c = prog[j]
        if c == '>':
            i += 1
        elif c == '<':
            i -= 1
        elif c == '+':
            if tape[i] == 255:
                tape[i] = 0
            else:
                tape[i] += 1
        elif c == '-':
            if tape[i] == 0:
                tape[i] = 255
            else:
                tape[i] -= 1
        elif c == '[':
            if tape[i] == 0:
                j = jumps[j]
        elif c == ']':
            if tape[i] != 0:
                j = jumps[j]
        elif c == 'h':
            break
        j += 1
        total += 1
        if total >= 100000:
            return total
    return total

def stringify(tape):
    return '[' + ''.join('{:3x}'.format(tape[i]) for i in range(min(tape), max(tape))) + ']'

print('\t')
for i in range(25):
    prog = randprog()
    tape = collections.defaultdict(int)
    total = execute(prog, tape)
    if total != -1:
        print(total, '\t', prog, stringify(tape))

#print(execute('+[><]', [0]))