buncode

#!/usr/bin/env python3

import collections
import os
import pdb
import pprint
import sys

def buncode(f):
    while True:
        c = f.read(1).decode()
        if not c:
            return
        if c == 'd':
            a = iter(buncode(f))
            yield collections.OrderedDict(zip(map(bytes.decode, a), a))
        elif c == 'i':
            i = ''
            while True:
                c = f.read(1).decode()
                if not c:
                    return
                if c == 'e':
                    yield int(i)
                    break
                else:
                    i += c
        elif c == 'l':
            yield list(buncode(f))
        elif c == 'e':
            return
        else:
            i = c
            while True:
                c = f.read(1).decode()
                assert c, i
                if c == ':':
                    yield f.read(int(i))
                    break
                else:
                    i += c

if len(sys.argv) == 2:
    f = open(sys.argv[1], 'rb')
else:
    f = os.fdopen(sys.stdin.fileno(), 'rb')
pprint.pprint(buncode(f).__next__())