[Python-ideas] kwargs for return

[Wes Turner]

On Saturday, January 26, 2019, Steven D'Aprano <steve at pearwood.info> wrote:
>
>
> Perhaps you should start by telling us *precisely* what the problem is
> that your subclass will solve. Because I don't know what your idea of
> dict unpacking is, and how it compares or differs from previous times it
> has been proposed.


Dataclasses initialization may be most useful currently implemented
syntactic sugar for a dict return value contract that specifies a variable
name (and datatype)?

Is there a better way to specify a return object interface with type
annotations that throws exceptions at runtime that dataclasses?


>
> Are there any other languages which support dict unpacking? How does it
> work there?


This about object destructuring in JS is worth a read:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Object_destructuring

Here are two simple cases:

"""
var o = {p: 42, q: true};
var {p: foo, q: bar} = o;

console.log(foo); // 42
console.log(bar); // true
"""

Does it throw an exception when a value is undefined?
You can specify defaults:

"""
var {a: aa = 10, b: bb = 5} = {a: 3};

console.log(aa); // 3
console.log(bb); // 5
"""


>
>
> --
> Steve
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