A set is a collection of values taken from some ordinal type. A set type declaration has the form:
TYPE T = SET OF Base
where Base is an ordinal type. The values of T are all sets
whose elements have type Base. For example, a variable whose
type is SET OF [0..1] can assume the following
values:
{} {0} {1} {0,1}
Implementations are expected to use the same representation for a SET OF T as for an ARRAY T OF BITS 1 FOR BOOLEAN. Hence, programmers should expect SET OF [0..1023] to be practical, but not SET OF INTEGER.