Rich Hickey: extensible data notation(github.com)

    (char "r" 0)
    > #\r

    static Pattern symbolPat = Pattern.compile("[:]?([\\D&&[^/]].*/)?([\\D&&[^/]][^/]*)");

    data Tree = Empty
              | Leaf Int
              | Node Tree Tree

    #tree/Tree Empty
    #tree/Tree [Leaf 42]
    #tree/Tree [Node #tree/Tree Empty, #tree/Tree [Leaf 42]]

    {"follows": ["ben", "billy-jo", "anon"]
    ,"message-counts": {"billy-jo-ben": 2}}

   2.2.  Objects

   An object structure is represented as a pair of curly brackets
   surrounding zero or more name/value pairs (or members).  A name is a
   string.  A single colon comes after each name, separating the name
   from the value.  A single comma separates a value from a following
   name.  The names within an object SHOULD be unique.

    (list 1 2 3)
    (vector 1 2 3)
    (hash-set :a :b :c)
    (hash-map :a 1 :b 2)