anchor.diff:  
   ==== Going further: 'spying' macros
   
  -Some Clojure libraries provide 'enhanced' versions of `prn` that are more informative, by also printing information 
  -about the wrapped expression. For example: 
  -
  -* the **https://github.com/clojure/tools.logging[tools.logging]** logging library 
  -provides a http://clojure.github.io/tools.logging/#clojure.tools.logging/spy[spy] macro to log an expression's code along 
  +Some Clojure libraries provide 'enhanced' versions of `prn` that are more informative, by also printing information
  +about the wrapped expression. For example:
  +
  +* the **https://github.com/clojure/tools.logging[tools.logging]** logging library
  +provides a http://clojure.github.io/tools.logging/#clojure.tools.logging/spy[spy] macro to log an expression's code along
   with its value
  -* the **https://github.com/dgrnbrg/spyscope[spyscope]** library lets you to insert these printing calls with very 
  +* the **https://github.com/dgrnbrg/spyscope[spyscope]** library lets you to insert these printing calls with very
   lightweight syntax.
   
   ==== Going further: tracing libraries
   
  -_Tracing_ libraries such as **https://github.com/clojure/tools.trace[tools.trace]** and **http://bpiel.github.io/sayid/[Sayid]**
  -can help you instrument larger portions of your code, for example by automatically printing all the function calls in a 
  +_Tracing_ libraries such as **https://github.com/clojure/tools.trace[tools.trace]** and **http://clojure-emacs.github.io/sayid/[Sayid]**
  +can help you instrument larger portions of your code, for example by automatically printing all the function calls in a
   given namespace, or all intermediary values in a given expression.
   
   === Intercepting and saving values on-the-fly
   
  -Sometimes you want to do more with intermediary values than just print them: 
  +Sometimes you want to do more with intermediary values than just print them:
   you want to save them to conduct further experiments on them at the REPL.
  -This can be done by inserting a `(def ...)` call inside the expression where the value appears: 
  +This can be done by inserting a `(def ...)` call inside the expression where the value appears:
   
   [source,clojure]
   ----
  
positive.code:   [numbers]
    (let [sum (first numbers)
          n (count numbers)]
      (/ 
        (doto sum prn) ;; HERE
        n)))
  ----
  
negative.code:   (println i "green bottles, standing on the wall. ♫")
    (Thread/sleep 1000))
  
  (future
    (run!
      print-number-and-wait
      (range)))
  
  