[Python-Dev] PEP 544: Protocols (original) (raw)

Matthias Kramm kramm at google.com
Mon Mar 20 17:11:54 EDT 2017

I'm a big fan of this. I really want structural subtyping for http://github.com/google/pytype.

On Mon, Mar 20, 2017 at 5:00 AM, Ivan Levkivskyi <levkivskyi at gmail.com> wrote:

Explicitly declaring implementation -----------------------------------

To explicitly declare that a certain class implements the given protocols,

Why is this necessary? The whole point of ducktyping is that you don't have to declare what you implement.

I get that it looks convenient to have your protocol A also supply some of the methods you'd expect classes of type A to have. But completing an implementation in that way should be done explicitly (via including a utility class or using a decorator like functools.total_ordering), not as side-effect of an (unnecessary) protocol declaration. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20170320/32ab6833/attachment.html>

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