Signature matching (ISCLASS)

The signature matching operator creates a property that determines, from a class perspective, whether the property specified in the operator can have a non-NULL value for the given arguments. In fact, this operator infers the possible classes of a given property from its semantics, and then, using logical operators and the classification operator, creates the required property.

Language

To implement this operator, use the ISCLASS operator.

Example

CLASS Person;
name = ABSTRACT CASE STRING[100] (Person);

CLASS Student : Person;
studentName = DATA STRING[100] (Student);

name(s) += WHEN ISCLASS(studentName(s)) THEN studentName(s); // is equivalent to WHEN s IS Student THEN studentName(s)