[Zope3-dev] Interface surprise

[Phillip J. Eby]

At 10:01 AM 3/31/03 -0500, Shane Hathaway wrote:
>I've been using the following idiom in Zope 2 to discover whether an 
>object is an interface definition:
>
>
>from Interface import Interface
>
>def isInterface(obj):
>     return Interface.isImplementedBy(obj)
>
>
>This idiom has a little surprise, though: any object that implements any 
>interface also implements Interface.  Since the above function yields 
>numerous false positives, I don't know the right way to detect whether an 
>object is an Interface.

I think you want IInterface.isImplementedBy().  However, it's probably 
reasonable for the Zope 3 interface API to export an 'isInterface' 
function, too.