Expand description
Index types that produce arrays.
The default rust index types, that is usize and those constructed with special range syntax,
produce slices. That’s not necessarily bad as designing them with const in mind would have
delay their introduction and have problems of coherency. The ergonomic overhead however muddles
the intent and requires writing a never failing, but semantically fallible conversion.
With the introduction of const generic parameters we can design a better solution with which
the length of the range is statically determined and which consequently can return a proper
array reference instead of a dynamically sized slice. Even better, as this happens in the type
system, some parameter values can be deduced where the compiler can match with another array
type!
Having to decide on the length introduces new complications that are usually put off to the
actual execution of indexing. If the given indices are inconsistent, i.e. the end is smaller
than the start or the end of an inclusive range is the maximum possible index, then there is no
possible type to represent the output. We will not solve this dilemma at the moment, and only
define the simple indices which is precisely RangeTo<usize>.
Structs
- A marker struct for statically sized range to (
..n).