anchor.diff:      dt))
   ----
   
  -Then the original application is reduced to:
  +Update the application at hello-world/src/hello.clj to use our library instead:
   
   [source,clojure]
   ----
  
positive.code: 
  Once in the REPL you can type Clojure expressions and press enter to evaluate them.
  
  There are many Clojure and Java libraries available that provide access to practically any functionality you might need. These may be libraries you are writing locally, projects in git (e.g. on github) or, commonly, libraries available in the Maven ecosystem and hosted by central repositories like Maven central or Clojars. 
  
  For example, consider the commonly used Clojure library https://github.com/clj-time/clj-time[clj-time] for working with dates and times. If you tried to use it at the REPL, it would fail:
  
  [source,clojure]
  ----
  user=> (require '[clj-time.core :as t])
  FileNotFoundException Could not locate clj_time/core__init.class or clj_time/core.clj on classpath.
  Please check that namespaces with dashes use underscores in the Clojure file name.
  ----
  
  The error message indicates that the `clj-time.core` namespace isn't on the JVM's classpath. The classpath specifies all of the places the JVM will look to load Clojure namespaces (or Java classes).
  
  Exit the REPL by typing Ctrl-D at the prompt to return to the terminal. Create a file in the current directory named `deps.edn`. This file is in the https://github.com/edn-format/edn[edn] data format, a subset of Clojure syntax. It contains a map with the well-known key `:deps` which is a map from library to coordinate:
  
  [source,clojure]
  ----
  
negative.code: * Running Clojure programs
  * Evaluating Clojure expressions
  
  In all the above scenarios you might want to use other Clojure and Java libraries (dependencies or 'deps'). These may be libraries you are writing locally, projects in git (e.g. on GitHub) or, commonly, libraries available in the Maven ecosystem and hosted by central repositories like Maven Central or Clojars.
  
  In all cases, using a library involves: +
  a) specifying which library you want to use, providing its name and other aspects like version +
  