objective c - Dot notation vs. message notation for declared properties

Question

We now have the "dot" notation for properties. I've seen various back and forths about the merits of dot notation vs. message notation. To keep the responses untainted I'm not going to respond either way in the question.

What is your thought about dot notation vs. message notation for property accessing?

Please try to keep it focused on Objective-C - my one bias I'll put forth is that Objective-C is Objective-C, so your preference that it be like Java or JavaScript aren't valid.

Valid commentary is to do with technical issues (operation ordering, cast precedence, performance, etc), clarity (structure vs. object nature, both pro and con!), succinctness, etc.

Note, I'm of the school of rigorous quality and readability in code having worked on huge projects where code convention and quality is paramount (the write once read a thousand times paradigm).

Answer 1

Do not use dot for behavior. Use dot to access or set attribute like stuff, typically attributes declared as properties.

x = foo.name; // good
foo.age = 42; // good

y = x.retain; // bad

k.release; // compiler should warn, but some don't. Oops.

v.lockFocusIfCanDraw; /// ooh... no. bad bad bad

For folks new to Objective-C, I would recommend not using the dot for anything but stuff declared as @property. Once you have a feel for the language, do what feels right.

For example, I find the following perfectly natural:

k = anArray.count;
for (NSView *v in myView.subviews) { ... };

You can expect that the clang static analyzer will grow the ability to allow you to check that the dot is being used only for certain patterns or not for certain other patterns.