| Guido van Rossum | c2e2074 | 2006-02-27 22:32:47 +0000 | [diff] [blame] | 1 | class GeneratorContextManager(object): |
| 2 | def __init__(self, gen): |
| 3 | self.gen = gen |
| 4 | |
| 5 | def __context__(self): |
| 6 | return self |
| 7 | |
| 8 | def __enter__(self): |
| 9 | try: |
| 10 | return self.gen.next() |
| 11 | except StopIteration: |
| 12 | raise RuntimeError("generator didn't yield") |
| 13 | |
| 14 | def __exit__(self, type, value, traceback): |
| 15 | if type is None: |
| 16 | try: |
| 17 | self.gen.next() |
| 18 | except StopIteration: |
| 19 | return |
| 20 | else: |
| 21 | raise RuntimeError("generator didn't stop") |
| 22 | else: |
| 23 | try: |
| 24 | self.gen.throw(type, value, traceback) |
| 25 | except (type, StopIteration): |
| 26 | return |
| 27 | else: |
| 28 | raise RuntimeError("generator caught exception") |
| 29 | |
| 30 | def contextmanager(func): |
| 31 | def helper(*args, **kwds): |
| 32 | return GeneratorContextManager(func(*args, **kwds)) |
| 33 | return helper |
| 34 | |