anchor.diff:  ** Good interoperability with Java libraries
   
   * Concurrency primitives in the standard library
  -** STM: agents, refs, atoms.
  +** STM: agents, refs, atoms, vars.
   
   * Prefers purely-functional programming styles and idioms
   ** Immutable data structures
   ** Imperative style is still possible, but de-emphasized
  +** Not particularly object-oriented
   
   == Clojure: Code
   
  
positive.code: .Example
  ------------------------------------------------------
  (defn indexable? [word]
    (> (count word) 2)
  (indexable? "to")               ; => false
  (indexable? "clojure")          ; => true
  (filter indexable? '("I" "am" "writing" "in" "clojure"))
                                  ; => ("writing" "clojure")
  ------------------------------------------------------
  
  - Parameter list: `[word]`. Square brackets construct a _vector_ (list
    with good random-access performance).
  - No need for sharp-quotes; `indexable?` by itself evaluates to the
    function object
  
  == Clojure: Maps
  
  == ClojureScript
  
  == That's it
  
  Questions?
negative.code: ------------------------------------------------------
  (defun square (x)
    (* x x))
  (square 4)                      ; => 16
  (mapcar #'square '(1 2 3 4 5))  ; => (1 4 9 16 25)
  (mapcar #'(lambda (x) (+ x 5))
          '(10 20 30))            ; => (15 25 35)
  