> Stefan, that sketch is more complicated than it needs to be - `np.copy` is a
> python function, so you can just attach the attributes directly! (although
> maybe there are implications for static typing)
For the type annotations we can simply use something akin to Stéfans proposed
`NpCopy` class;
probably in combination with `Protocol`.
It's a bit more work compared to annotating a normal python function, but it's
quite easy nevertheless.
Regards, Bas
________________________________
From: NumPy-Discussion
<numpy-discussion-bounces+bas.vanbeek=hotmail....@python.org> on behalf of Eric
Wieser <wieser.eric+nu...@gmail.com>
Sent: 21 June 2021 18:56
To: Discussion of Numerical Python <numpy-discussion@python.org>
Subject: Re: [Numpy-discussion] copy="never" discussion and no deprecation
cycle?
Stefan, that sketch is more complicated than it needs to be - `np.copy` is a
python function, so you can just attach the attributes directly! (although
maybe there are implications for static typing)
```
class CopyFlag(enum.Enum):
IF_NEEDED = 0
ALWAYS = 1
NEVER = 2
np.copy.IF_NEEDED = CopyFlag.IF_NEEDED
np.copy.ALWAYS = CopyFlag.ALWAYS
np.copy.NEVER = CopyFlag.NEVER
```
It would also work nicely for the `True/False/other` version that was proposed
in the much older PR as `np.never_copy`:
```
class _CopyNever:
def __bool__(self): raise ValueError
np.copy.NEVER = _CopyNever()
```
All of these versions (and using the enum directly) seem fine to me.
If we go down the enum route route, we probably want to add "new-style"
versions of `np.CLIP` and friends that are true enums / live within a more
obvious namespace.
Eric
On Mon, 21 Jun 2021 at 17:24, Stefan van der Walt
<stef...@berkeley.edu<mailto:stef...@berkeley.edu>> wrote:
On Sun, Jun 20, 2021, at 20:46, Gagandeep Singh wrote:
> I have recently joined the mailing list and have gone through the previous
> discussions on this thread. I would like to share my analysis (advantages and
> disadvantages) of three possible alternatives (Enum, String, boolean) to
> support the proposed feature.
Thanks for this thorough analysis, Gagandeep!
I'll throw one more heretical idea out there:
`np.copy.IF_NEEDED`, `np.copy.ALWAYS`, `np.copy.NEVER`.
This has the advantages of the enum, doesn't pollute the global namespace, and
has an intuitive name.
`np.array(x, copy=np.copy.ALWAYS)`
It would be slightly more awkward to type, but is doable. A rough Python
version sketch would be:
class CopyFlag(enum.Enum):
IF_NEEDED = 0
ALWAYS = 1
NEVER = 2
class NpCopy:
IF_NEEDED : CopyFlag = CopyFlag.IF_NEEDED
ALWAYS : CopyFlag = CopyFlag.ALWAYS
NEVER : CopyFlag = CopyFlag.NEVER
def __call__(self, x):
return ...whatever copy returns...
np.copy = NpCopy()
Stéfan
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