[Python-3000] Need help completing ABC pep (original) (raw)

Bill Janssen janssen at parc.com
Fri Apr 20 21:07:04 CEST 2007

Guido,

A good start. A few comments:

Where do strings and bytes fit in? They seem to be sequences. Are they sub-typable? If so, shouldn't their base interface be defined?

I'd either add numeric types to this, or split it in two pieces: one about ABCs in general (perhaps defining Comparable and Object), and another for collection types. Then a third for numeric types.

I don't like the name of the "pop()" method on Sets. It's too much associated with stacks. People reading code that uses "pop" on a value will naturally assume that the value is a stack. I'd prefer "remove_and_return_random_item()".

Python will not require that a class derives from BasicMapping or Sequence when it defines a getitem method,

Good.

nor will the x[y] syntax require that x is an instance of either ABC.

Good.

You will still be able to assign any "file-like" object to sys.stdout, as long as it has a write method.

Well, yes, but... I think there should be an ABC for "file-like", which the standard "file" and "StringIO" implementations inherit from. This could even be a fourth PEP.

Bill

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