cpython/Lib/test/contextmanager.py
Guido van Rossum c2e20744b2 PEP 343 -- the with-statement.
This was started by Mike Bland and completed by Guido
(with help from Neal).

This still needs a __future__ statement added;
Thomas is working on Michael's patch for that aspect.

There's a small amount of code cleanup and refactoring
in ast.c, compile.c and ceval.c (I fixed the lltrace
behavior when EXT_POP is used -- however I had to make
lltrace a static global).
2006-02-27 22:32:47 +00:00

34 lines
929 B
Python

class GeneratorContextManager(object):
def __init__(self, gen):
self.gen = gen
def __context__(self):
return self
def __enter__(self):
try:
return self.gen.next()
except StopIteration:
raise RuntimeError("generator didn't yield")
def __exit__(self, type, value, traceback):
if type is None:
try:
self.gen.next()
except StopIteration:
return
else:
raise RuntimeError("generator didn't stop")
else:
try:
self.gen.throw(type, value, traceback)
except (type, StopIteration):
return
else:
raise RuntimeError("generator caught exception")
def contextmanager(func):
def helper(*args, **kwds):
return GeneratorContextManager(func(*args, **kwds))
return helper