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: "Now, there will be a new subdirectory named getting-data.

A block of code is set as follows:

(defproject getting-data "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.6.0"]])

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

(defn watch-debugging
  [input-file]
  (let [reader (agent
                 (seque
                   (mapcat
                     lazy-read-csv
                     input-files)))
        caster (agent nil)
        sink (agent [])
        counter (ref 0)
        done (ref false)]
    (add-watch caster :counter
               (partial watch-caster counter))
    (add-watch caster :debug debug-watch)
    (send reader read-row caster sink done)
    (wait-for-it 250 done)
    {:results @sink
     :count-watcher @counter}))

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

$ lein new getting-data
Generating a project called getting-data based on the default template. To see other templates (app, lein plugin, etc), try lein help new.

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: "Take a look at the Hadoop website for the Getting Started documentation of your version. Get a single node setup working".

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.