Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: “We define a new constant value by using the let keyword.”

A block of code is set as follows:

let phrase: String = "The quick brown fox jumps over the lazy dog"

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

let steve = Person.init(givenName: "Steven",

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

<#What to append#> >> <#Where to append it#>

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: “From here, in the toolbar on your Mac, click File > New > Playground…”

Tips or important notes

Appear like this.