A Basic Introduction to Swift

This chapter presents an overview of the Swift programming language, focusing on Swift Foundation Library, C Library Interoperability, and memory management. The Swift standard library provides support for basic data types, protocols, collections, and more. Swift developers are accustomed to leveraging a library called Grand Central Dispatch, which provides concurrent execution support in their applications. This library has also been made available on Linux and is now included as one of the core libraries in the Swift runtime. Dispatch provides support for submitting work to DispatchQueues. Work submitted to these queues is run across a number of threads managed by the system. ARC accounts for Swift programs maintaining a very low memory footprint compared to other interpreted or JVM‐based languages. ARC keeps track of memory used by class instances and frees up that memory when those instances are no longer being referenced. Weak references are converted to nil when the object they are referencing is freed. IBM and Apple built over a hundred rich iOS applications for the enterprise.