[Python-Dev] PEP 575 (Unifying function/method classes) update (original) (raw)

Ronald Oussoren ronaldoussoren at mac.com
Sun Jun 17 13:52:06 EDT 2018

On 17 Jun 2018, at 16:31, Stefan Behnel <stefanml at behnel.de> wrote:

Ronald Oussoren schrieb am 17.06.2018 um 14:50: Why did you add a tpccalloffset slot to the type with the actual information in instances instead of storing the information in a slot? If the configuration of the callable was in the type, you would need a separate type for each kind of callable. That would quickly explode. Think of this as a generalised PyCFunction interface to arbitrary callables. There is a function pointer and some meta data, and both are specific to an instance.

That’s true for PyCFunction, but not necessarily as a general replacement for the tp_call slot. I my code I’d basically use the same function pointer and metadata for all instances (that is, more like PyFunction than PyCFunction).

Also, there are usually only a limited number of callables around, so memory doesn't matter. (And memory usage would be a striking reason to have something in a type rather than an instance.)

I was mostly surprised that something that seems to be a replacement for tp_call stores the interesting information in instances instead of the type itself.

Ronald

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