Among
Among a set of values
Signature
among(val: Alpha|AttrName, vals: Set<Alpha>) -> Predicate
Examples
among(:status, [10, 30])
Description
This predicates checks whether val belongs to the set of values vals.
Implementation notes
The set vals may only contain pure values, attribute names are not
supported. Any enumerable of such values is supported in practice, e.g.
an Array literal.