Chrisian,
How would these namedtuple/structseq values be used? I have a similar design
with PyObjC: pass-by-reference “return” values are returned in a tuple, e.g.:
void getpoint(pointclass* v, int* x, int *y) => def get point(v:
pointless) -> (int, int)
BOOL getvalue(someclass* v, int* val) => def getvalue(v: someclass)
-> (bool, int)
I rarely, if ever, see code that actually stores the return tuple as-is. The
return tuple is just deconstructed immediately, like “x, y =
getpoint(mypoint)”.
Ronald
—
Twitter: @ronaldoussoren
Blog: https://blog.ronaldoussoren.net/
> On 8 Aug 2019, at 10:42, Christian Tismer <tis...@stackless.com> wrote:
>
> Hi Guido,
>
> If a C++ function already has a return value, plus some primitive
> pointer variables that need to be moved into the result in Python,
> then we have the case with a first, single unnamed field.
> Only one such field can exist.
>
> I'm not sure if that case exists in the ~25000 Qt5 functions, but in
> that case, I think to give that single field the name "unnamed"
> or maybe better "result".
>
> Thank you very much for pointing me to that example!
>
> Cheers -- Chris
>
>
> On 08.08.19 06:41, Guido van Rossum wrote:
>> Alas, we didn't think of struct sequences when we designed PEP 484. It
>> seems they are a hybrid of Tuple and NamedTuple; both of these are
>> currently special-cased in mypy in ways that cannot easily be combined.
>>
>> Do you really need anonymous fields?
>>
>> I see an example in typeshed/stdlib/3/os/__init__.pyi (in
>> github.com/python/typeshed <http://github.com/python/typeshed>), for
>> stat_result. It defines names for all the fields, plus a __getitem__()
>> method that indicates that indexing returns an int. This doesn't help if
>> anonymous fields could have different types, not does it teach the type
>> checker about the number of anonymous fields.
>>
>> --Guido
>>
>> On Wed, Aug 7, 2019 at 1:51 AM Christian Tismer <tis...@stackless.com
>> <mailto:tis...@stackless.com>> wrote:
>>
>> Hi all,
>>
>> Ok, I am about to implement generation of such structures
>> automatically using the struct sequence concept.
>>
>>
>> One more question:
>> ------------------
>>
>> Struct sequences are not yet members of the typing types.
>> I would like to add that, because a major use case is also to
>> show nice .pyi files with all the functions and types.
>>
>> * namedtuple has made the transition to NamedTuple
>>
>> * What would I need to do that for StructSequence as well?
>>
>> Things get also a bit more complicated since struct sequence
>> objects can contain unnamed fields.
>>
>> Any advice would be appreciated, I am no typing expert (yet :-)
>>
>> cheers -- Chris
>>
>>
>> On 30.07.19 17:10, Guido van Rossum wrote:
>>> I think I have to agree with Petr. Define explicit type names.
>>>
>>> On Tue, Jul 30, 2019 at 2:45 AM Paul Moore <p.f.mo...@gmail.com
>> <mailto:p.f.mo...@gmail.com>
>>> <mailto:p.f.mo...@gmail.com <mailto:p.f.mo...@gmail.com>>> wrote:
>>>
>>> On Tue, 30 Jul 2019 at 09:33, Christian Tismer
>> <tis...@stackless.com <mailto:tis...@stackless.com>
>>> <mailto:tis...@stackless.com <mailto:tis...@stackless.com>>>
>> wrote:
>>> > >>> typing.NamedTuple("__f", x=int, y=int)
>>> > <class '__main__.__f'>
>>> > >>> typing.NamedTuple("__f", x=int, y=int) is
>> typing.NamedTuple("__f",
>>> > x=int, y=int)
>>> > False
>>>
>>> This appears to go right back to collections.namedtuple:
>>>
>>> >>> from collections import namedtuple
>>> >>> n1 = namedtuple('f', ['a', 'b', 'c'])
>>> >>> n2 = namedtuple('f', ['a', 'b', 'c'])
>>> >>> n1 is n2
>>> False
>>>
>>> I found that surprising, as I expected the named tuple type to be
>>> cached based on the declared name 'f'. But it's been that way
>> forever
>>> so obviously my intuition here is wrong. But maybe it would be
>> useful
>>> for this case if there *was* a way to base named tuple
>> identity off
>>> the name/fields? It could be as simple as caching the results:
>>>
>>> >>> from functools import lru_cache
>>> >>> cached_namedtuple = lru_cache(None)(namedtuple)
>>> >>> n1 = cached_namedtuple('f', ('a', 'b', 'c')) # A tuple rather
>>> than a list of field names, as lists aren't hashable
>>> >>> n2 = cached_namedtuple('f', ('a', 'b', 'c'))
>>> >>> n1 is n2
>>> True
>>>
>>> Paul
>>>
>>>
>>>
>>> --
>>> --Guido van Rossum (python.org/~guido <http://python.org/~guido>
>> <http://python.org/~guido>)
>>> /Pronouns: he/him/his //(why is my pronoun here?)/
>>>
>>
>> <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
>>>
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>>
>>
>> --
>> Christian Tismer :^) tis...@stackless.com
>> <mailto:tis...@stackless.com>
>> Software Consulting : http://www.stackless.com/
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>>
>>
>> --
>> --Guido van Rossum (python.org/~guido <http://python.org/~guido>)
>> /Pronouns: he/him/his //(why is my pronoun here?)/
>> <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
>>
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>
>
> --
> Christian Tismer :^) tis...@stackless.com
> Software Consulting : http://www.stackless.com/
> Karl-Liebknecht-Str. 121 : https://github.com/PySide
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> phone +49 173 24 18 776 fax +49 (30) 700143-0023
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