The Constraints paragraph allows specification of properties of
parameters of a parameterized class, and therefore allows the use of methods or
properties on data items whose type is specified as that parameter.
General Format

Syntax Rules
- Parameter-name-1 must be a parameter of the class in which this
Constraints paragraph is specified.
General Rules
- If the IMPLEMENTS phrase is specified, parameter-name-1 must be
of a class that implements the interface interface-name-1.
- If the INHERITS phrase is specified, parameter-name-1 must
inherit directly or indirectly from class-name-1.
- If the NEWABLE phrase is specified, the class of parameter-name-1
must include a constructor with no parameters.
- If VALUE TYPE or VALUETYPE is specified, the type of
parameter-name-1 must be a value type. If REFERENCE TYPE is specified, the type
of parameter-name-1 must be a reference type.
- Items whose type is specified as parameter-name-1 may be
specified where an item of class class-name-1 or interface-name-1 is required.
- Items whose type is specified as parameter-name-1 have all the
methods and properties of a class-name-1 and interface-name-1