package Discr21_Pkg istype Position is record
x,y,z :Float;end record;type Dim is(Two, Three);type VPosition (D: Dim := Three)is record
x, y :Float;case D iswhen Two =>null;when Three => z :Float;end case;end record;function To_Position (x, y, z :Float)return VPosition;end Discr21_Pkg;