Review Mojo's priorities

• I have read the roadmap and priorities and I believe this request falls within the priorities.

What is your request?

Allow using the syntax s[idx, label="test"] for fn __getitem__[*, label: String](self, idx: Int) -> R. Note that if both label and idx are runtime/compile-time, the syntax works fine; this feature request is for support when there is a mix of them

What is your motivation for this change?

• Achieve better uniformity between runtime and compile-time APIs.
• Enable interesting API designs such as:

struct Pointer:
  ...
  fn __getitem__[type: DType, //, *, size](self: Pointer[Scalar[type]], offset: Int) -> SIMD[dtype, size]:
    ...

fn main():
  p[idx, size=simd_width]

Any other details?

N/A