Question

You can use a standard dot notation or a method call in Objective-C to access a property of an object in Objective-C.

myObject.property = YES; 

or

[myObject setProperty:YES]; 

Is there a difference in performance (in terms of accessing the property)? Is it just a matter of preference in terms of coding style?

Answer 1

Dot notation for property access in Objective-C is a message send, just as bracket notation. That is, given this:

@interface Foo : NSObject @property BOOL bar; @end  Foo *foo = [[Foo alloc] init]; foo.bar = YES; [foo setBar:YES]; 

The last two lines will compile exactly the same. The only thing that changes this is if a property has a getter and/or setter attribute specified; however, all it does is change what message gets sent, not whether a message is sent:

@interface MyView : NSView @property(getter=isEmpty) BOOL empty; @end  if ([someView isEmpty]) { /* ... */ } if (someView.empty) { /* ... */ } 

Both of the last two lines will compile identically.