In both python 3.7 and 3.8, typing.NamedTuple had some strange behaviour
regarding multiple inheritance. This behaviour was solved in 3.9
(bpo-36517), but this fix also barred me from a feature very close to my
heart: the generic named tuple
```
T = TypeVar('T')
class LLNode(NamedTuple, Generic[T]
Hi all, I recently ran into a problem trying to adapt mypy into an older
codebase, and it got me thinking about a potential addition to the typing
library.
This idea comes in two parts (that can even be taken individually): the
first is to allow the False singleton literal to be used in type
annot
Hi all, decorators are a very powerful feature in python, but it's syntax
is strangely restrictive.
decorator ::= "@" dotted_name ["(" [argument_list [","]] ")"] NEWLINE
for 99% of cases this is not a hindrance, but sometimes we'd rather be able
to use full expression syntax. consider the follow
changing this, but it keeps coming up, and in other
> cases we don’t restrict the grammar (except when there are real
> ambiguities). So maybe the SC can accept a PRP for this?
>
> On Mon, Feb 3, 2020 at 15:47 Ben Avrahami wrote:
>
>> Hi all, decorators are a very powerful featur
Hey all,
Often I've found this kind of code:
seen = set()
for i in iterable:
if i in seen:
... # do something in case of duplicates
else:
seen.add(i)
... # do something in case of first visit
This kind of code appears whenever one needs to check for duplicates in
case of a user-s
On Thu, Jun 25, 2020 at 6:44 PM Alex Hall wrote:
> Previous discussions on this:
>
>
> https://mail.python.org/archives/list/[email protected]/thread/ASHOHN32BQPBVPIGBZQRS24XHXFMB6XZ/
>
> https://mail.python.org/archives/list/[email protected]/thread/K5SS62AB5DFFZIJ7ASKPLB2P3XGSYFPC/
On Thu, Jun 25, 2020 at 7:55 PM Christopher Barker
wrote:
> On Thu, Jun 25, 2020 at 9:02 AM Steele Farnsworth
> wrote:
> indeed -- and that is pretty darn baked in to Python, so I don't think
> it's going to change.
>
>
Except this convention doesn't hold for dict.setvalue (which I did
misspell,
consider the following function:
def foo(a,b,c,x):
pass
The following calls are equivalent:
foo(1,2,3, x=0)
foo(*(1,2,3), x=0)
However, since python allows keyword arguments before star-unpacking, you
can also do:
foo(x=0, *(1, 2, 3))
But removing the unpacking, would resul
Hey all, I recently ran into some trouble and that I think deserves some
attention. Consider the following case:
class A(ABC):
@abstractmethod
def __lt__(self, other):
pass
@dataclass(order=True)
class B(A):
x: int = 0
class C(B):
pass
On Thu, Sep 24, 2020 at 6:59 PM Guido van Rossum wrote:
> Interesting problem. Since the solution is just updating
> `__abstractmethods__`, this could be done in the `@dataclass` decorator, no
> new ABC needed.
>
>
This issue also pertains to total_ordering (and perhaps other std library
class-de
On Thu, Sep 24, 2020 at 7:02 PM Eric V. Smith wrote:
> Does anyone know if attrs handles this? I don't have a recent version
> installed, but I'll take a look later today.
>
attrs handles this only if you set slots=True (which makes sense since
attrs would have to rebuild the class)
On Tue, Sep 29, 2020 at 4:53 PM Bar Harel wrote:
> I'd like to bring another insight to the table: According to the pep,
> "Dynamically
> adding abstract methods to a class, or attempting to modify the abstraction
> status of a method or class once it is created, are not supported."
>
> The noti
ed to modify `__abstractmethods__` and perform abstract logic on
their own- I don't see why the standard library should keep such
computations unavailable.
On Tue, Sep 29, 2020 at 6:41 PM Eric V. Smith wrote:
> On 9/29/2020 10:49 AM, Ben Avrahami wrote:
>
> On Tue, Sep 29, 2020 at 4:53
mented, overruling whatever
> the PEP says?
>
> On Wed, Sep 30, 2020 at 00:01 Ben Avrahami wrote:
>
>> I encountered this problem when I needed to implement a class that
>> defined all 4 of the comparison operators, once with `dataclass` (for one
>> implementation) and once
t 1, 2020 at 5:08 PM Guido van Rossum wrote:
> That might work (though not for older Python versions). What kind of API
> were you thinking of for adding and deleting abstract methods?
>
> On Thu, Oct 1, 2020 at 01:07 Ben Avrahami wrote:
>
>>
>>
>> I suppose it'
Hi all, this is a general feeler for if this idea has any traction:
All too often I see the following pattern in asyncio 3rd-party libs, either
in their own source code or in the inusage:
```
inst = SomeClass()
await inst.initialize()
```
What happens here is that, since coroutines cannot be used
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