1 @interface Foo 2 @end 3 4 @interface Foo(Top) 5 -(void)top; 6 @end 7 8 @interface Foo(Top2) 9 -(void)top2; 10 @end 11 12 @interface Foo(Top3) 13 -(void)top3; 14 @end 15 16 @protocol P1 17 @end 18 19 @protocol P2 20 @end 21 22 @protocol P3, P4; 23 24