Question

In Objective-C i saw that we can use dot operator to set and get a value and for the same task i saw something like “[ob method]” inside square braces method call, what do we call for this kind of syntax?

Answer 1

Bracket notation: A staple of the small talk language, and now a lovely visage of the ObjC language.

Brackets were SmallTalk’s way of saying “You there, take this message and do something with it”, and so that’s how they were implemented in Objective C. We send a message to the first part [Object] and state the message in the second part [Object Message];

Of course, they also serve a similar function with properties. Properties in most languages are written in dot notation (Object.property), but with Objective-C and the modern runtime’s support for non-ivar-backed properties, and the @synthesize directive, properties automatically generate getters named the same. Sounds complicated? It isn’t. If I have the property example, then I can access it in one of two ways:

self.example; 

Or

[self example];

Easy!

But the @synthesize directive doesn’t stop there. We get a getter, and a setter as well. The setter can be accessed the same number of ways as a getter.

self.example = foo;

is the equivalent of

[self setExample:foo];

Bracket notation is in fact so important, that the compiler optimizes most dot notation out to bracket notation at compile time.