[munificent]

Since Codon performs static type checking ahead of time, a few of Python's dynamic features are disallowed. For example, monkey patching classes at runtime (although Codon supports a form of this at compile time) or adding objects of different types to a collection.

This seems like a very different language from Python if it won't let you do:

    [1, 'a string']

[didip]

I welcome this change. I am willing to sacrifice a few Python features for the sake of speed.

[jnxx]

I have been using Python since 25 years, and never needed that one.

[ris]

You've never had to read arbitrary json?

[insanitybit]

I just did a quick check (apparently DuckDuckGo has a built in JSON validation function lol love it) and `[1, "foo"]` does pass their JSON validation.

Not surprised but I did want to confirm.

[okayexplainl4]

Am I missing something, why wouldn't a non-homogeneous array literal pass?

[insanitybit]

Because mixing types in an array is stupid enough that I thought it might just not be valid.

[ris]

Mixing types in an array/list is not remotely stupid. How exactly would you suggest expressing the lack of a value in a series of numbers without None/null? There's your mixed types.

Don't let weird dogma get in the way of practicality.

[bombolo]

You never implemented a quick polish notation calculator that uses this data structure? [1,2, '+']

[chenzhekl]

I would use two stacks, one of which stores numbers and the other stores operators.

[bombolo]

Why? Just to have no unions of types?

[joshmaker]

In 25 years you’ve never once created a list with more than one type of object in it?

[throwaway894345]

I mean, it depends on what you mean by “type”. A list of some Protocol type (what other languages call “interfaces”) is still a homogenous list even though the concrete types are heterogeneous. This is almost always what you want when you’re thinking of “a heterogeneous list”.

[bombolo]

It's not unheard of to have unions and a couple of if isinstance.

In fact it's why in python they even have the | operator between types nowadays.

[mangecoeur]

I have also been using python a long time and i honestly can’t remember a time i used mixed type list.

[querez]

In my code this comes up often, e.g. when I use tuples instead of namedtuple or a dataclass.

[bastawhiz]

Tuples aren't lists though. Tuples are really just structs with indexes instead of names.

[ris]

Never have to handle/forward function calls with arbitrary arguments? What do you think *args is?

[mangecoeur]

a tuple

[froggit]

I use mixed lists all the time to store shit, but I'm also a total python newb that really doesn't know better.

[cjohnson318]

Maybe a list with ThingObject or None, but my lists are usually homogenous.

[mrfox321]

thats just homogenous Sequence[Optional[T]], though.

[cjohnson318]

Yeah, that's a better way of putting it :) 90% of the time, I'm something like Sequence[T], but I'm sure I've used Sequence[Optional[T]] a couple of times. I mean, I could drive donuts in the Piggly Wiggly parking lot at 3a, I just don't, and the same for heterogenous lists.

[agumonkey]

And everything is a subtype of Any. The usual 'static typing' of dynlangs.

[bombolo]

well list[int|str] is as well

[gautamdivgi]

I’ll second that. I’ve been doing python for a while and haven’t used the mixed type list. I’ve actively avoided doing something like that. The situation doesn’t come up often.

[terhechte]

Same here. If I needed that I might use a tuple.

[amelius]

And then it crashes when you convert it to JSON.

[UncleEntity]

I just use an extension wrapper around boost::property_tree for my json (and xml) needs. Way faster than the built in json support and does automagic type conversion so I don’t have to worry about it.

Now, I’m not running at Web Scale™ but pure python was slow enough to be annoying.

[eddsh1994]

Huh, thinking about it I haven't in 9 years either

[qwefsdf]

With type hints you would model this as a Union type, i.e., Union[int, str]. This is perfectly legal with mypy and other Python type checkers.

[__mharrison__]

Not "Python", but if you are doing that in Python, then you are doing it wrong.