anchor.diff:  (greet-dog "Sparky")
   ;; => "Woof woof Sparky!"
   ----
  +
  +== Anonymous Functions
  +
  +An anonymous function is a function without a name.
  +In Clojure these can be defined in two ways, `defn` and the literal `#(...)`.
  +Creating a function with `defn` immediately binds it to a name, `fn` just creates a function.
  +
  +Lets go back to the example of the bands.
  +We wrote a function called `rock-band?` to determine whether or not our band was a rock band.
  +This is a one-off operation, we're not going to use it anywhere else in our code.
  +We can save ourselves some keystrokes by using an anonymous function.
  +
  +[source, clojure]
  +----
  +(def rock-bands
  +    (filter 
  +        (fn [band] (= :rock (:genre band))) 
  +        bands))
  +----
  +
  +Even more concisely, using the function literal, we can define `rock-bands` like so.
  +
  +[source, clojure]
  +----
  +(def rock-bands (filter #(= :rock (:genre %)) bands))
  +----
  +    
  +The function literal supports multiple arguments via `%1`, `%2`, and so on.
  +
  +[source, clojure]
  +----
  +#(println %1 %2 %3)
  +----
  +
  +If you're writing an anonymous function, the literal syntax is nice because it's so compact.
  +However, beyond a few arguments, the syntax can become difficult to read.
  +In that case, using `fn` may be more appropriate.
  +
  +
  +
  +
  +
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positive.code: 
  [source, clojure]
  ----
  (def bands [
      {:name "Kiss"
       :genre :rock}
      {:name "Led Zeppelin"
       :genre :rock}
      {:name "Michael Jackson"
       :genre :pop}
      {:name "Eminem"
       :genre :rap}])
  
  (defn rock-band? 
      [band]
  
negative.code: (add-five 100)
  ;; => 105
  ----
  
  The returned function form `adder` is a closure.
  This means, it can access all of the variables that we're in scope when the function was created.
  `add-five` has access to `x` even though it is outside of the `adder` function definition.
  
  === Functions as Arguments
  
  Our second function is going to be a factory of sorts.
  We're going to call it, `make-greeter`.
  