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: "If you want an integer type back, you can use the div and rem functions."

A block of code is set as follows:

defmodule MyMap do
  def map([], _) do
    []
  end

  def map([h|t], f) do
    [f.(h) | map(t, f)]
  end
end

square = fn x -> x * x end
MyMap.map(1..5, square)

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

iex(1)> IO.puts("Hello, World!")
Hello, World!
:ok
iex(2)>

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: "This is the basis of what functional languages call pattern matching and is really one of the fundamental things that makes functional programming so different and so exciting."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.