Foundation in Swift 3: Understanding the Swift 3 Update - raywenderlich.com

Описание: In this video, you'll learn how to use Foundation types in Swift 3 and the reasoning behind the changes.

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About Swift (from Wikipedia)

Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. for iOS, macOS, watchOS, tvOS, and Linux. Swift is designed to work with Apple's Cocoa and Cocoa Touch frameworks and the large body of extant Objective-C (ObjC) code written for Apple products. Swift is intended to be more resilient to erroneous code ("safer") than Objective-C, and more concise. It is built with the LLVM compiler framework included in Xcode 6 and later and, on platforms other than Linux, uses the Objective-C runtime library, which allows C, Objective-C, C++ and Swift code to run within one program.

Swift supports the core concepts that made Objective-C flexible, notably dynamic dispatch, widespread late binding, extensible programming and similar features. These features also have well-known performance and safety trade-offs, which Swift was designed to address. For safety, Swift introduced a system that helps address common programming errors like null pointers, and introduced syntactic sugar to avoid the pyramid of doom that can result. For performance issues, Apple has invested considerable effort in aggressive optimization that can flatten out method calls and accessors to eliminate this overhead. More fundamentally, Swift has added the concept of protocol extensibility, an extensibility system that can be applied to types, structs and classes. Apple promotes this as a real change in programming paradigms they term "protocol-oriented programming".

Swift was introduced at Apple's 2014 Worldwide Developers Conference (WWDC). It underwent an upgrade to version 1.2 during 2014 and a more major upgrade to Swift 2 at WWDC 2015. Initially, a proprietary language, version 2.2 was made open-source software and made available under Apache License 2.0 on December 3, 2015, for Apple's platforms and Linux. IBM announced its Swift Sandbox website, which allows developers to write Swift code in one pane and display output in another.

A second free implementation of Swift that targets Cocoa, Microsoft's Common Language Infrastructure (.NET), and the Java and Android platform exists as part of the Elements Compiler from RemObjects Software.[20] Since the language is open-source, there are prospects of it being ported to the web.[21] Some web frameworks have already been developed, such as IBM's Kitura, Perfect[22][23] and Vapor. An official "Server APIs" work group has also been started by Apple,[24] with members of the Swift developer community playing a central role.

About Swift 3 (from https://www.raywenderlich.com/135655/...)

Community members submitted over 100 proposals for changes to Swift since it went open source. A large number of them (70 so far) have been accepted after discussion and modification. Those that have been rejected have sparked some intense discussion as well. In the end however, the core team makes the final decision on all proposals.

The collaboration between the core team and the wider community has been impressive. In fact, Swift has garnered 30 thousand stars on Github. Several new proposals are submitted every week, week-after-week. Even Apple engineers pen proposals on open Github repository when they want to make changes.

In the sections below, you’ll see linked tags such as [SE-0001]. These are Swift Evolution proposal numbers. The links to each proposal have been included so you can discover the full details of each particular change. You can also check the status of all Swift Evolution proposals to see which ones have been implemented. The code examples below build on Paul Hudson’s excellent overview of the common changes you’ll notice in Swift 3.

Swift 3 fixes bugs in the compiler and IDE features. It also improves the precision of error and warning messages. And as you might expect, with each release, Swift is getting faster in how it runs and compiles:

By improving string hashing there was a 3x speedup in dictionaries of strings

By moving objects from the heap to the stack there was a 24x
speedup (in some cases)

The compiler now caches multiple files at once (when doing whole module optimization)

Code size optimization has reduced the compiled size of Swift code. Apple’s demo Demobots reduced the compiled size to 77% of the original