On Mon, Feb 15, 2021, 11:34 AM David Mertz <me...@gnosis.cx> wrote:
> On Mon, Feb 15, 2021 at 4:19 PM Guido van Rossum <gu...@python.org> wrote:
>
>> Okay, here’s my dilemma. It looks like this thread wants to devise a new
>> syntax for lambda, using e.g. (x, y) -> x+y, or the same with =>. That’s
>> great, but doesn’t open new vistas. OTOH, for people using type
>> annotations, a much more pressing issue is an alternative for
>> typing.Callable that is more readable, and supports extra features that
>> Callable doesn’t, like keyword args, varargs, and pos-only.
>>
>
> FWIW, I *do not* want an alternate spelling for lambda.
>
> If your time machine were still working, and you could go back to 1991 to
> change the spelling, yes I might like that. For that matter, if someone
> had a good spelling for multi-line lambdas, I might like that. Or *maybe*
> some other difference in behavior, but nothing comes immediately to mind.
>
> But allowing a few cryptic punctuation symbols to express an anonymous
> function while still retaining "the name of a cryptic greek letter" to do
> exactly the same thing seems like a strong non-goal.
>
> That said, if I had to look at one, I'd like '->' much better than '=>'.
>
I also don't see this as a very worthwhile goal.
But if we could expand the proposal to allow both anonymous and named
functions, that would seem like a fantastic idea to me.
Anonymous function syntax:
(x,y)->x+y
Named function syntax:
f(x,y)->x+y
But since Guido wants to save the right shaft operator for type hinting,
and named functions do need a way to write type hints, maybe the best thing
to do is use an equal sign shaft for the function definition and the right
shaft for the type hint:
f(x,y)=>x,y->str
>>> f('a','b')
'ab'
>>> f(1,2) # type hint error
Rick.
>
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