Calling a method if the receiver does respond to it.

gistfile1.txt

-(BOOL)performSelectorIfResponding:(SEL)selector withObjects:(id)firstParameter, ... {
    if (![self respondsToSelector:selector]) {
        return NO;
    }
    
    NSMethodSignature* signature = [self.class instanceMethodSignatureForSelector:selector];
    NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:signature];
    invocation.target = self;
    invocation.selector = selector;
    
    NSUInteger i = 2;
    va_list parameters;
    va_start(parameters, firstParameter);
    for (id parameter = firstParameter; parameter; parameter = (va_arg(parameters, id))) {
        [invocation setArgument:&parameter atIndex:i];
        i++;
    }
    va_end(parameters);
    
    [invocation invoke];
    
    return YES;
}