Question

There are three different syntax styles for accessing properties of an object:

myProp = value;
self.myProp = value;
[self setMyProp: value];

Are these purely style choices or is there difference in substance?

Answer 1

self.myProp = value;

and

[self setMyProp: value];

are style choices, as they are using accessors to set values. That is, self.myProp essentially is the same as calling [self setMyProp] or [self myProp]. It will implement whatever mechanism you define in the @property tag (retaining, releasing as needed, etc).

However,

myProp = value;

is substantially different as it is simply an assignment. No consideration for releasing myProp‘s original pointer, retaining the new value, etc.