[Python-Dev] API for binary operations on Sets (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Thu Sep 30 14:38:19 CEST 2010

On Thu, Sep 30, 2010 at 1:50 PM, Raymond Hettinger <raymond.hettinger at gmail.com> wrote:

1a.  Liberalize setobject.c binary operator methods, restrict SetABC methods, and add named methods (like difference, update, etc) that accept any iterable.

2. We could liberalize builtin set objects to accept any iterable as an "other" argument to a binary set operator.  This choice is not entirely backwards compatible because it would break code depending on being able run ror, rand, etc after a NotImplemented value is returned.  That being said, I think it unlikely that such code exists.  The real disadvantage is that it replicates the problems with list.add and Guido has said before that he doesn't want to do that again.

I was leaning towards #1 or #1a and the guys on IRC thought #2 would be better.  Now I'm not sure and would like additional input so I can get this bug closed for 3.2.  Any thoughts on the subject would be appreciated. Thanks,

My own inclination would be to go with #1a, unless Guido chimes in to say he's OK with having the set operators accept arbitrary iterators.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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