> For better interfacing to other programming languages, the symbols of enum
types can be assigned an explicit ordinal value. However, the ordinal values
must be in ascending order.
<https://nim-lang.org/docs/tut1.html#advanced-types-enumerations>

> Integers, bool, characters, and enumeration types (and subranges of these
types) belong to ordinal types.
<https://nim-lang.org/docs/manual.html#types-ordinal-types>

> An array is a simple fixed-length container. Each element in an array has the
same type. The array's index type can be any ordinal type.
<https://nim-lang.org/docs/tut1.html#advanced-types-arrays>