Conventions

In this book, you will find a number of styles of text 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: "Apply the readString function to the input, and get all date documents."

A block of code is set as follows:

main :: IO () 
main = do 
  input <- readFile "input.txt"
  print input

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

main :: IO () 
main = do 
  input <- readFile "input.txt"
  print input

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

$ runhaskell Main.hs

New terms and important words are shown in bold. Words that you see on the screen, in menus, or dialog boxes for example, appear in the text like this: "Under the Downloads section, download the cabal source package."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.