[Python-Dev] Duck-typing self (original) (raw)

Steven Bethard steven.bethard at gmail.com
Thu Feb 19 00:30:14 CET 2009

On Wed, Feb 18, 2009 at 2:32 PM, Sebastian Rittau <srittau at jroger.in-berlin.de> wrote:

Hi!

I am curious why the following will not work in Python: class foo(object): def bar(self): print self.attr class duck(object): attr = 3.14 foo.bar(duck()) Is it a design decision that duck-typing self does not work or is there a technical reason? From a practical standpoint it seems that being able to duck-type self has merit, for example in unit testing complex classes.

Works for me in 3.0:

Python 3.1a0 (py3k:69082, Jan 28 2009, 19:22:10) [MSC v.1500 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information.

class Foo(object): ... def bar(self): ... print(self.attr) ... class Duck(object): ... attr = 3.14 ... Foo.bar(Duck()) 3.14

Steve

I'm not in-sane. Indeed, I am so far out of sane that you appear a tiny blip on the distant coast of sanity. --- Bucky Katt, Get Fuzzy

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