[Python-Dev] Simpler reformulation of C inheritance Q.

[Christian Tismer]

Michael Hudson wrote:

[slots in types]

> I would wonder how much this saves.
> 
> How many more instructions does
> 
>   PyDict_GetItem(ob->ob_type->tp_dict, interned_string)
> 
> take than
> 
>   ob->ob_type->tp_my_field->mf_my_method
> 
> ?  Sure, *some* but not all that many esp. if the called function is
> actually doing significant work.

The comparison doesn't hit the nail (as you explain
as well), since what I do right now is to call
a highly optimized C function, directly, and the
speed concerns are mainly for my C API, which is
supposed to be much faster then the Python interface.

Having to call anything but my builtin stuff hurts.
So I want at least to 'know' that my function is
not overridden, and be able to call the builtin stuff.
Doing the call all the time via

ob->ob_type->tp_my_field->mf_my_method

would be nice, but I'd even be pleased with some flag.
But there is no space for nothing in a type.

Second, this is most time critical code, since my
tasklet switching is now very fast (half the time
of a function call from Python) for my CFrames.
And now people ask for overriding there, which hurts
me most possible. I will either find the solution,
or leave it as it is and ask C programmers to
"grab the thing if you want the overridden method".

...

> I doubt my opinion counts here, but I think I'd prefer to see *less*,
> not more, methods in type object in future.  Particularly if there's
> some way to call functions with known signatures efficiently.
> Unfortunately, that seems pretty hard after five minutes thinking.

I'm not going to introduces masses of new methods for
type objects, but a generic way to introduce private
stuff.

not-easy-to-stop-me-anyway-at-all-ly y'rs -- chris

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