Re:Grids in Rust, Part 2: const generics
by dathinab on Sunday April 04, 2021 @02:50AM
(#26687436)
They also have arrays which size is not known at compiler time (`[T]` instead of `[T; SIZE]`).
It's just that you (for now(1)) can't put dynamic sized types (DST) on the stack, but you can coerce a `&[T; SIZE]` to a `&[T]`. The later has the size encoded in the pointer. Which combined with rusts system to compiler time enforce proper aliasing and RAII allows nice sub-slicing like e.g the `split` at method which allows splitting a `&[T]` into two non-overlapping `&[T]`'s.
(1): There is ongoing work to allow DST on the stack in some limited circumstances which would help with some things, but I'm not the biggest fan of it. For example because this is in many but not all cases incompatible with `async/await` and the not yet existing generators.
It's just that you (for now(1)) can't put dynamic sized types (DST) on the stack, but you can coerce a `&[T; SIZE]` to a `&[T]`. The later has the size encoded in the pointer. Which combined with rusts system to compiler time enforce proper aliasing and RAII allows nice sub-slicing like e.g the `split` at method which allows splitting a `&[T]` into two non-overlapping `&[T]`'s.
(1): There is ongoing work to allow DST on the stack in some limited circumstances which would help with some things, but I'm not the biggest fan of it. For example because this is in many but not all cases incompatible with `async/await` and the not yet existing generators.