anchor.diff:  Java comparators are all 3-way, meaning they return a negative, 0, or positive integer depending upon whether
   the first argument should be considered less than, equal to, or greater than the second argument.
   
  -In Clojure, you may also use boolean comparators that return _true_ if the first argument should come before
  -the second argument, or _false_ otherwise (i.e. should come after, or it is equal).
  -The function _<_ is a perfect example, as long as you only need to compare numbers. _>_ works for sorting
  +In Clojure, you may also use boolean comparators that return `true` if the first argument should come before
  +the second argument, or `false` otherwise (i.e. should come after, or it is equal).
  +The function `<` is a perfect example, as long as you only need to compare numbers. `>` works for sorting
   numbers in decreasing order.
  -Behind the scenes, when such a Clojure function _bool-cmp-fn_ is "called as a comparator",
  +Behind the scenes, when such a Clojure function `bool-cmp-fn` is "called as a comparator",
   Clojure runs code that works like this to return an _int_ instead:
   
   [source,clojure]
  
positive.code:   (<= (second a) (second b)))
  ----
  
  The boolean comparator _by-2nd-<=_ seems to work correctly on the first step of creating the set,
  but fails when testing whether elements are in the set.
  
  [source, clojure]
  
negative.code: 
  ifdef::env-github,env-browser[:outfilesuffix: .adoc]
  
  _Note: This document describes Clojure 1.7 and Java 6, but applies to most other versions as well._
  
  == Summary
  
  