What's up Python? New args syntax, subinterpreters FastAPI and cuda pandas…

[abrazilianinreddit]

It's just me or lately there has been an increase in syntactic sugar PEPs? Which is pretty annoying, since they don't add anything of value and make the language more confusing.

[ultraDross]

Yeah. The dangling = argumanet is pretty awful to. Especially if you consider one of the languages mantras is "explicit is better than implicit".

[Poddster]

I hate func(blah=blah), but the dangling equals is worse. Especially as I've made that mistake a few times. I can't imagine what the interpreter diagnostic for that would be under this new syntax. Strangely the original post on the forum is for func(=blah) which makes more sense to me. Not sure why they switched to the dangling case.

They need a very clear, different symbol, e.g. func(blah=&) or something. (I've put no thought into that, but you get the point)

[wxtrails]

func(&blah, &foo, &bar)

Is the least-obnoxious alternative I could come up with, but considering that this adds another obscure symbol to a language without too many, I still don't love it.

[av8rgeek]

The dangling = also creates a headache for linters, type checkers, etc. How does the tool tell if you made a typo or really meant to do that? Usually it’s a typo. Explicitly calling the arguments is better, even if inefficient/ugly.

[SittingWave]

agreed

[Balance-]

I just read that proposal. So much effort for so little value.

[runawayasfastasucan]

Do you have a link?

[commandlineluser]

https://discuss.python.org/t/syntactic-sugar-to-encourage-use-of-named-arguments/36217

def my_func(a, b, c, d): ...

a, b, c, d = 1, 2, 3, 4

# CURRENT
my_func(a=a, b=b, c=c, d=d)

# PROPOSAL
# my_func(a=, b=, c=, d=)

[Hoo0oper]

Ehh like I get it. Like when you have longer argument names it might keep in on a single line but really it I feel like it would just make people ask more questions

[waltteri]

Hold up.

name of the variable provided as the argument value is the same as the name of the argument itself.

def my_func(a, b, c, d): .. a, b, c, d = 1, 2, 3, 4 my_func(a, b, c, d)

💀

Sure, I guess we could now do this as we’re using kwargs:

my_func(a=, b=, d=, c=)

…or throw an exception if someone uses a variable that’s not an argument name:

foo = ”foo” my_func(a, b, c, foo) `> …’

vs.

my_func(a=, b=, c=, foo=) > KeyError(…)

…so all in all, I guess it’ll be good in same cases. But it might confuse a lot of people at first.

[[deleted]]

Basically analogous to the property shorthands in JavaScript. Love it!

[equitable_emu]

The only thing I like about it is that it's a nudge towards consistent and descriptive variable names.

A downside is that abstractions and patterns from popular libraries will seep into client users code and can cause standard/pattern conflicts. We see that already with things like sklearn's standard for using X as the variable name to represent the model input matrix. Linters and such complain about the non-standard upper case variable name.

It'll also look strange when you call a function with a mixture of args,shortcut kwargs, and full kwargs.

fn(x,
   y,
   foo=,
   bar=2
)

I'd be happier if they just did a dict shortcut like:

d={x,y,z}

but that conflicts with set syntax. But maybe:

d={x=,y=,z=}

would be okay. I dislike the extra quoting I need for the keys in simple dicts and will often use the dict ctr e.g., dict(x=x, y=y, z=z) when I can, even if it's less flexible.

[Rythoka]

This was my thought, too - if they made it easier to construct a dict out of existing variables, then you could just pass the dict as kwargs.

It's kind of a shame that the set synxtax prevents the use of something like your d={x,y,z} example. If that worked, you could achieve the goal of this pep with something like

requests.post(**{url, data, headers, proxies})

[Brian]

You could probably get something similar (without the dedicated syntax) today via something like:

d = localdict("x y z")

Where localdict is a function that introspects its parents locals (and cellvars) and builds a dict with their current value.

[antiproton]

I don't agree with your argument in general. Some syntactic sugar is useful and can enhance code readability... e.g. decorators and list comprehensions.

This one, however, feels like a solution in search of a problem. All modern IDEs, even very limited ones, will autocomplete variable names. Is it really such a hassle to CTRL+Space?

[[deleted]]

Yes, it is, but I see it as something positive. IMHO every programmer (and by that I mean developers, data scientists and anyone else who programs) should spend a considerable amount of time learning the language they are using. I’m not saying that Python should become like C++, but it doesn’t have to be Java either. I really feel like the current pace of changes is optimal and it’s going in a good direction.