Abstract: A system is presented for optimizing safe downcasting and similar programming idioms in an object-oriented programming language. The system operates by receiving a source program written in the object-oriented programming language. The system compiles this source program into an intermediate representation. Next, the system examines the intermediate representation to identify the use of a virtual function call to determine if an object of a given base class is a member of a given derived class. Such usage facilitates safe downcasting of the object from the given base class to the given derived class. If the intermediate representation uses the virtual function call in this manner, the system replaces the virtual function call with a comparison of a virtual function table pointer associated with the object to an address of a virtual function table associated with the given derived class. The compiler finishes compiling the intermediate representation into executable binary code.

Abstract: The lower stringer of a slide fastener means is attached to an upstanding side wall of a sole, which side wall extends around the perimeter of the sole; the complementary upper stringer is attached to the lower edge portion of the upper, which loser edge portion extends around the perimeter of said upper. With the shoe disassembled, the tape of the upper stringer lies adjacent of the outer surface of the upper and carries coupler means directed upwardly. To assemble the shoe, the upper stringer tape is folded outwardly and downwardly over on itself to form an upwardly directed bight and thus dependently locating the coupler means of the upper stringer directly above the coupler means of the lower stringer so that slide fastener means can couple the two said coupler means. A removable heel cup, for reinforcing the heel region of the upper, is upwardly insertable into a heel pocket formed in the rear of the upper.