NAME: in

        FUNCTION:  Tests for set membership

        OPERAND TYPE:
                      Left Operand: any ordinal type t;
                      Right operand: set whose base is compatible with t.


        RESULT TYPE:  Boolean

        NOTES:

           When the operands =, <>, <, >, >=, or <= are of simple
           types, they must be compatible types; however, if one
           operand is of a real type, the other can be of an integer
           type.

           Strings are compared according to their extended ASCII
           charactor set.  Charactor type values are treated as
           string types.

           Packed strings can be compared if they have the same
           number of components.

           Pointers are equal only if they point to the same object.
           Only equal, <, >, are valid pointer comparison operators.

           Sets are compared according to its members.
           a = b is True only if a and b contain exactly the same
           members;  otherwise, a <> b.
           a <= b is True only if every member of a is also a member
           of b.
           a >= b is True only if every member of b is also a member
           of a.

           When using the IN operator, it will return true when the
           value of the ordinal type operand is a member of the set
           type operand.