Testulator | Python Fiddle

def proc_bool_eval(in_bool):
    return 'T' if in_bool else 'F'

def proc_bool(in_char):
    return False if in_char == 'F' else True

def char_move(in_char, change):
    return chr(ord(in_char)+ change)

def proc_not(in_char):
    return proc_bool_eval(not proc_bool(in_char))

def proc_and(char1, char2):
    return proc_bool_eval(proc_bool(char1) and proc_bool(char2))
    
def proc_or(char1, char2):
    return proc_bool_eval(proc_bool(char1) or proc_bool(char2))

def proc_xor(char1, char2):
    return proc_bool_eval(proc_bool(char1) != proc_bool(char2))

def process(optcode, screen, next_optcode):
    if optcode == 'C':
        return ''
    if optcode == 'D':
        return screen + next_optcode
    if optcode == 'F':
        return screen[0] + screen
    if optcode == 'G':
        return char_move(screen[0], -1) + screen[1:]
    if optcode == 'H':
        return char_move(screen[0], 1) + screen[1:]
    if optcode == 'J':
        return ''.join(sorted(screen))
    if optcode == 'M':
        return proc_not(screen[0]) + screen[1:]
    if optcode == 'N':
        return proc_and(screen[0], screen[1]) + screen[2:]
    if optcode == 'P':
        return proc_xor(screen[0], screen[1]) + screen[2:]
    if optcode == 'Q':
        return proc_or(screen[0], screen[1]) + screen[2:]
    if optcode == 'R':
        return screen[-1] + screen[:-1]
    if optcode == 'S':
        return next_optcode + screen
    if optcode == 'T':
        return ('TRUE' if proc_bool(screen[0]) else 'FALSE') + screen[1:]
    if optcode == 'W':
        return screen[1:]
    if optcode == 'X':
        return screen[1] + screen[0] + screen[2:]
    if optcode == 'Z':
        return screen[::-1]
    raise Exception('UNKNOWN OPCODE' + optcode)
    
def run_program(instructions):
    instructions = instructions +'0'
    screen = 'OK'
    skip_next = False
    for i, optcode in enumerate(instructions[:-1]):
        if skip_next:
            skip_next = False
            continue
        next_optcode = instructions[i+1]
        try:
            screen = process(optcode, screen, next_optcode)
        except IndexError:
            return None
        skip_next = optcode in ['S', 'D']
        #print 'After {}, screen is {}'.format(optcode, screen)
    return screen

def try_all():
    opt_bank = 'CDFGHJMNPQRSTWXZ'
    for l1 in opt_bank:
        for l2 in opt_bank:
            for l3 in opt_bank:
                for l4 in opt_bank:
                    for l5 in opt_bank:
                        instructions = ''.join([l1, l2, l3, l4, l5,])
                        result = run_program(instructions)
                        print instructions + ' yielded ' + str(result)
                        if result == 'TESLA':
                            return 
if __name__ == "__main__":
#    run_program('CDFFDTMNQT')
#    run_program('XHFRNFGDAJDEZX')
    try_all()

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