Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Download the toolchain file"

A block of code is set as follows:

h5> oneMillion = "one million"
error: repl.swift:11:12: error: cannot assign to value: 'oneMillion' is a
'let' constant
oneMillion = "one million"
~~~~~~~~~~~^
repl.swift:2:1: note: change 'let' to 'var' to make it mutable`
let oneMillion = 1\_000\_000`
^~~~
var

Any command-line input or output is written as follows:

$ swift

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Next, you select the Toolchain you want to develop against, which will only change the Xcode settings"

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.