isa operator
The isa operator is a binary operator that tests whether an expression resolves to a particular EGL part. The logical expression resolves to TRUE if the expression matches the part identified; otherwise it resolves to FALSE. The most common purpose of the operator is to test the type of the data in an ANY type field.
Syntax

- testExpression
- A numeric, text, or date/time expression. The expression can be a single field or literal.
- partSpecification
- A part specification. The specification can be a system-defined part (like a primitive part), or a user-defined part. If you can specify the primitive part with a length (for example, CHAR(25)), partSpecification must include a length specifier. partSpecification can be a dynamic array.