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In my previous entry, I discussed when id will be promoted to instancetype. But now that I’ve explained this, I’d like to explain why you should understand this but not rely on it. Instead, you should use instancetype directly.

Let me start with this bold statement, then I’ll back up and explain it: Use instancetype whenever it’s appropriate, which is whenever a class returns an instance of that same class.

Continue reading “Why you should use instancetype instead of id”

instancetype is a special type that can be returned from an Objective-C method. It specifies that the return is an object of the same type as the receiving class. In some cases, the compiler promotes an id return to an instancetype: For instance, despite the definition of [[NSString alloc] init], the compiler knows that it returns an NSString.

Continue reading “When is id promoted to instancetype?”

Properties were new in Objective-C 2.0, introduced in 2006. While pretty uncontroversial, along with them came dot syntax. Dot syntax is much more controversial.

In this article, I’ll discuss the advantages of @property which make it worth using, and discuss “dot syntax.”

Continue reading “A primer on @property and dot syntax”

I’d like to propose a new language feature for Objective-C, a property attribute that would indicate that a property should only be set from the main thread.

Let me be clear: Objective-C does not do this. But wouldn’t it be cool if it did?

Continue reading “Objective-C property proposal: mainthreadonly”

I haven’t seen this discussed anywhere, but you can eliminate a level of indentation when using @synchronized and @autoreleasepool blocks in a loop or conditionally. This falls naturally as a result of the way the C language works, and how these blocks work, but it took me a while to realize it.

Continue reading “Trimming a level of indent with @synchronized and @autoreleasepool”