MODULE D1;
    VAR x*   : INTEGER  (* x is visible (read-only) in other modules *)
        y, z : BOOLEAN; (* y and z are not visible to other modules *)
    PROCEDURE P1*; (* P1 can be called from other modules *)
        VAR   lv1, lv2  : INTEGER;
        PROCEDURE Sub1;
        BEGIN (* Sub1 body *)
            (* lv1, lv2 not visible here *)
        END Sub1;
    BEGIN (* P1 body *)
        (* x, y, z, lv1, lv2 and Sub1 visible here *)
    END P1;

BEGIN (* D1 body *)
    (* x, y, z and P1 visible here *)
END D1.