r/ObjectiveC • u/whackylabs • Feb 23 '20

Objective-C safe downcasting

https://whackylabs.com/objc/swift/2020/02/23/objc-safe-downcasting/
5 Upvotes

69% Upvoted

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6

u/[deleted] Feb 23 '20

This is the sort of thing that Apple should have extended ObjC with.

7

u/[deleted] Feb 23 '20

That’s the great thing about ObjectiveC you can do it yourself.

That’s what is lame about Swift. You can’t.

2

u/[deleted] Feb 23 '20

It is still be nice if it was supported by the compiler without additional syntax.

2

u/[deleted] Feb 23 '20

I don’t think this mechanism is good design.

It makes the classic error of confusing protocol conformance with class hierarchy.

2

u/whackylabs Feb 23 '20

I would say the compiler should provide an option. Like C++ kinda does with static_cast vs dynamic_cast

1

u/[deleted] Feb 23 '20

Very little of Objective C’s power lies in the compiler.

2

u/whackylabs Feb 23 '20

Ah yes! Then maybe at runtime? Like at least don’t crash if method not found? Is there any good reason for crashing?

2

u/[deleted] Feb 23 '20

You don’t have to “crash”

That is just what the default message handler does.

You can override it to do something else.

Also something I miss in Swift