Conventions used

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

CodeInText: 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: "The persistence protocol ServiceDB consists of upsert, entity, and delete functions."

A block of code is set as follows:

{
  "query": {
    "term": {
      "status": "O"
    }
  }
}

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 home-page
  [request]
  (log/counter ::home-hits 1)
  (ring-resp/response "Hello World!"))

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

% lein run
Noname | Hello, World!

% lein run Clojure
Clojure | Hello, World!

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Click on the Create a visualization button."