Re: Presenting PEP 695: Type Parameter Syntax

Yeah, we all would have liked angle brackets, but there would be problems
with breaking lines between those. E.g.

def foo<
    T: str,
    S: int
> (arg1: T, arg2: S) -> tuple[T, S]:
    ...

cannot be parsed because the lexer doesn't treat angle brackets as matching
pairs.

In addition, we already use square brackets for *using* generics (e.g.
list[int]), and most surveyed languages use the same type of brackets in
declarations and uses.

On Thu, Jul 14, 2022 at 1:10 PM <[email protected]> wrote:

> Hi, I like this PEP but I couldn't find the motivation for using angle
> brackets over square braces (brackets?). The survey in Appendix A is great
> but lacks any conclusions. From that survey alone I would assume that angle
> brackets would have been chosen over square braces, given that they are the
> most common option and appear in (afaik) the more popular languages in that
> list. I think the PEP should add a section about the choice of syntax in
> the rejected section, which can be expanded upon in Appendix A.
>
> If you can't tell I'm in favor of angle brackets, I think the examples
> given in the PEP look a bit messy with so many parentheses and square
> braces in close proximity. Using angle brackets would make the distinction
> between typevars and function parameters clearer.
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