Question

okay so I want to make a public function that will return YES if an object exists, conforms to a protocol and responds to a selector. I know the typedef of @selector is SEL but what is the typedef for @protocol

BOOL conforms(id object, ? prototype, SEL action) {
  return (object != nil && 
         [object conformsToProtocol:prototype] && 
         [object respondsToSelector:action]);
}

And I want to be able to call this function like:

if(conforms(delegate, @protocol(UIScrollViewDelegate), 
   @selector(touchesBegan:withEvent:))) {
  [delegate touchesBegan:touches withEvent:event];
}

Answer 1

You’re looking for the Protocol object:

BOOL conforms(id object, Protocol *protocol, SEL action) {
  return (object != nil && 
         [object conformsToProtocol:protocol] && 
         [object respondsToSelector:action]);
}