import sys

def typename(t):

    name = type(t).__name__

    if sys.version_info < (2,5):

        if name == 'classobj' and issubclass(t, MyException):

            name = 'type'

        elif name == 'instance' and isinstance(t, MyException):

            name = 'MyException'

    return "<type '%s'>" % name

class MyException(Exception):

    pass

class ContextManager(object):

    def __init__(self, value, exit_ret = None):

        self.value = value

        self.exit_ret = exit_ret

    def __exit__(self, a, b, tb):

        print("exit %s %s %s" % (typename(a), typename(b), typename(tb)))

        return self.exit_ret

    def __enter__(self):

        print("enter")

        return self.value

def no_as():

    """

    >>> no_as()

    enter

    hello

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with ContextManager("value"):

        print("hello")

def basic():

    """

    >>> basic()

    enter

    value

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with ContextManager("value") as x:

        print(x)

def with_pass():

    """

    >>> with_pass()

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with ContextManager("value") as x:

        pass

def with_return():

    """

    >>> print(with_return())

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    value

    """

    with ContextManager("value") as x:

        return x

def with_break():

    """

    >>> print(with_break())

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    a

    """

    for c in list("abc"):

        with ContextManager("value") as x:

            break

        print("FAILED")

    return c

def with_continue():

    """

    >>> print(with_continue())

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    enter

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    c

    """

    for c in list("abc"):

        with ContextManager("value") as x:

            continue

        print("FAILED")

    return c

def with_exception(exit_ret):

    """

    >>> with_exception(None)

    enter

    value

    exit <type 'type'> <type 'MyException'> <type 'traceback'>

    outer except

    >>> with_exception(True)

    enter

    value

    exit <type 'type'> <type 'MyException'> <type 'traceback'>

    """

    try:

        with ContextManager("value", exit_ret=exit_ret) as value:

            print(value)

            raise MyException()

    except:

        print("outer except")

def with_real_lock():

    """

    >>> with_real_lock()

    about to acquire lock

    holding lock

    lock no longer held

    """

    from threading import Lock

    lock = Lock()

    print("about to acquire lock")

    with lock:

        print("holding lock")

    print("lock no longer held")

def functions_in_with():

    """

    >>> f = functions_in_with()

    enter

    exit <type 'type'> <type 'MyException'> <type 'traceback'>

    outer except

    >>> f(1)[0]

    1

    >>> print(f(1)[1])

    value

    """

    try:

        with ContextManager("value") as value:

            def f(x): return x, value

            make = lambda x:x()

            raise make(MyException)

    except:

        print("outer except")

    return f

def multitarget():

    """

    >>> multitarget()

    enter

    1 2 3 4 5

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with ContextManager((1, 2, (3, (4, 5)))) as (a, b, (c, (d, e))):

        print('%s %s %s %s %s' % (a, b, c, d, e))

def tupletarget():

    """

    >>> tupletarget()

    enter

    (1, 2, (3, (4, 5)))

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with ContextManager((1, 2, (3, (4, 5)))) as t:

        print(t)

class GetManager(object):

    def get(self, *args):

        return ContextManager(*args)

def manager_from_expression():

    """

    >>> manager_from_expression()

    enter

    1

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    enter

    2

    exit <type 'NoneType'> <type 'NoneType'> <type 'NoneType'>

    """

    with GetManager().get(1) as x:

        print(x)

    g = GetManager()

    with g.get(2) as x:

        print(x)