Subrange types

A subrange type is a range of values from an ordinal or floating point type (the base type). To define a subrange type, one must specify its limiting values — the lowest and highest value of the type. For example:

type
  Subrange = range[0..5]
  PositiveFloat = range[0.0..Inf]

Subrange is a subrange of an integer which can only hold the values 0 to 5. PositiveFloat defines a subrange of all positive floating point values. NaN does not belong to any subrange of floating point types. Assigning any other value to a variable of type Subrange is a panic (or a static error if it can be determined during semantic analysis). Assignments from the base type to one of its subrange types (and vice versa) are allowed.

A subrange type has the same size as its base type (int in the Subrange example).