On 11/3/21 9:07 AM, Chris Angelico wrote:
> On Thu, Nov 4, 2021 at 2:29 AM Ethan Furman wrote:
>> One similarity that I don't think has been mentioned yet:
>>
>> - decorator syntax says, "run me later, after this function is built"
>>
>> - late-bound argument syntax says, "run me later, just before each function
call"
>
> Hmm, I more think of decorator syntax as "modify this function". It
> runs at the same time that the def statement does, although the
> effects may be felt at call time (including a lot of simple ones like
> lru_cache).
Well, if "at the same time" you mean "after the function is defined even though the decorator appears first", then sure.
;-)
>> Because both mean "run me later" we can leverage the @ symbol to aid
understanding; also,
>> because "run me later" can completely change the workings of a function
(mutable defaults,
>> anyone?), it deserves more attention than being buried in the middle of the
expression where
>> it is easy to miss (which is why I originally proposed the ? -- it stood out
better).
>
> One of the reasons I want to keep the latebound vs earlybound
> indication at the equals sign is the presence of annotations. I want
> to associate the lateboundness of the default with the default itself;
I think that level of specificity is unnecessary, and counter-productive. When discussing a particular late-bound
default, how are you (usually) going to reference it? By name: "the 'spam' parameter is late-bound" -- so decorate the
variable name.
> So if you want to make use of the at sign, it would end up looking like
matrix multiplication:
>
> def func(spam: list @= []) -> str: ...
> def func(spam: list =@ []) -> str: ...
>
> rather than feeling like decorating the variable.
Which is horrible. Put the @ at the front:
- its relation to decorators, and delayed evaluation, is much more clear
- it stands out better to the reader
--
~Ethan~
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