Apple WWDC 2014 announced a new programming language Swift, Swift Apple platform for future programming languages. Since then, many third-party developers to start using Swift to write programs, but Apple iOS and macOS systems, as well as various systems or applications written using Objective-C.
This situation exists for many reasons, first of all, Apple is the perfect large number of Objective-C code works, it is not necessary to rewrite and rewrite, no problem, do not create new problems. Secondly, until Swift 5.0, ABI becomes stable, Swift 5.1, the module stability is important for large-scale deployment at the system level.
Since iOS 9, developer Alexandre Colucci has been used in case of Swift statistical Apple system. The latest data show that in iOS 13 in a total of 141 written using Swift binary executable file, which is twice iOS 12 more, iOS 12 has 66.
iOS, 13, Sidecar deputy screen, find and reminders and other new features, new applications are written using Swift, Swift's use other app including health, Books e-books as well as some system services, and is responsible for AirPods HomePod matching services, and find App offline search function.
From: cnBeta