[Python-ideas] Exploiting type-homogeneity in list.sort() (again!)

[David Mertz]

On Tue, Mar 7, 2017 at 4:36 PM, Erik <python at lucidity.plus.com> wrote:

> * listextend() - this should do the right thing with the type hint when
>> extending one list with another.
>>
>
> * Several other methods ('contains', 'remove', 'count', 'index') also use
> PyObject_RichCompareBool(). They could also presumably benefit from the
> same optimisation (perhaps it's not all about sort() - perhaps this gives a
> little more weight to the idea).


Good point about list.extend().  I don't think __type_hint__ could help
with .__contains__() or .count() or .remove().  E.g.:

In [7]: lst = [1.0, 2.0, 1+0j, F(1,1)]
In [8]: from fractions import Fraction as F
In [9]: lst = [1.0, 2.0, 1+0j, F(1,1)]
In [10]: 1 in lst
Out[10]: True
In [11]: lst.count(1)
Out[11]: 3
In [12]: l.index(1)
Out[12]: 0


The list has absolutely nothing of the right type.  Yet it contains an
item, counts things that are equal, finds a position for an equal item.

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