[Python-Dev] Alternative to more ABCs [was:] Iterable String Redux (aka String ABC) (original) (raw)

Raymond Hettinger python at rcn.com
Sun Jun 1 05:09:10 CEST 2008

[Raymond]

I propose the following empty abstract classes: String, Datetime, Deque, and Socket.

[GvR]

Sounds like a mini-PEP is in place. It should focus on the code to actually define these and the intended ways to use them.

Okay, will run a Google code search to see if real code exists that runs isinstance tests on the concrete types. Since the new classes are very lightweight (completely empty), these probably only need minimal justification.

The case for String has already been made. And the concept of a Socket is already fully abstract. Not sure I really care about Deque.

The Datetime.class is tricky. The existence of many implementations of date/time routines indicates that there is a need; however, they don't share the API so they likely won't fit under a common umbrella.

Are you open to considering numbers.Integral to be one of the new empty abstract classes? That would make it much easier for objects wanting to pass themselves as integers. As it stands now, an aspiring Integral class is required to implement a number of arcana including: rxor, rrshift, pow, invert, index, and long. I don't think Integer should be completely abstract (what good is an int you can't add 1 to?) but I could be amenable to reducing the set of required operations (which could then resurface as a separate ABC). Please write another mini-PEP.

Okay. Will propose to remove the bit flipping methods and anything else that doesn't seem essential to integeriness. Will take a look at the integral types in numeric to see what that actually implement.

Where did you see long? That seems a mistake (at least in 3.0).

It's the first listed abstract method in the Py2.6 code.

Raymond

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