[Python-Dev] Py2.5 release schedule (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Sun Jul 30 23:34:30 CEST 2006

Fred L. Drake, Jr. schrieb:

On Sunday 30 July 2006 15:44, Barry Warsaw wrote: > if isinstance(obj, ClassType) or isinstance(obj, type(type))

Looks like you've got a possible name clash in the second isinstance. ;-)

Nah, that's rather an entry to the obfuscated Python contest. The two occurrences of type really mean to refer to the same thing; this is the test whether obj is a new-style class.

Normally, you would write isinstance(obj, type), but that gives a TypeError in 2.1 (isinstance() arg 2 must be a class or type). In 2.1, type(type) is FunctionType, so the test should fail (in the context, as obj ought to be a string, an exception object, or an exception type). In 2.2 and later, we have

type(type) is type 1 # sometimes True instead

I think I would have rewritten as

try:

Instantiate it if possible and necessary

exc = exc() except AttributeError: # no call; it's already an object pass

(assuming that the mailman exceptions don't have call) or as

if not isinstance(exc, Exception): exc = exc()

(assuming that string exceptions are gone, but the code below already assumes that exc should be an object that supports exc.reason_notice())

Regards, Martin

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