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: "With the where clause we are requiring that the elements in the iterator, within the E type, must be of the Integer type"

A block of code is set as follows:

protocol ZombieObserver {  
  func turnLeft() 
  func turnRight()  
  func seesUs() 
} 

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

Making a copy of internalQueue 

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: "From this menu, we will
want to select the Create a new Xcode project option."

Warnings or important notes appear in a box like this.

Tips and tricks appear like this.