[Python-Dev] Semantic of isinstance (original) (raw)

Martin Maly Martin.Maly at microsoft.com
Tue Jun 27 05:04:41 CEST 2006

Thanks for the response. The code snippet I sent deals with new style classes only so I assume that in some cases isinstance falls back to old-style-like handling which then asks for bases and class etc, possibly incorrectly so on new style classes.

Thanks again! Martin

-----Original Message----- From: Greg Ewing [mailto:greg.ewing at canterbury.ac.nz] Sent: Monday, June 26, 2006 8:00 PM To: Martin Maly Cc: python-dev at python.org Subject: Re: [Python-Dev] Semantic of isinstance

Martin Maly wrote:

isinstance(D(), D) True

isinstance(D(), C) D.getclass True

This looks like a new/old class thing. Presumably once everything is changed over to new-style classes, this inconsistency will go away. And from the current behaviour, it looks like class and bases will be bypassed by isinstance() (unless Guido decides to change that).

-- Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | Carpe post meridiem! | Christchurch, New Zealand | (I'm not a morning person.) | greg.ewing at canterbury.ac.nz +--------------------------------------+

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