anchor.diff:  ----
   
   Super and Sub Script::
  +`simp sub`, `simp super` and `simp sub super` are converted to a Hash of the following form.
   +
   [source]
   ----
  
positive.code: = Asciimath Grammar and AST
  
  == Grammar
  
  The syntax for ASCIIMath in EBNF style notation is
  
  [source]
  ----
  
negative.code: The parser returns an abstract syntax tree consisting of symbols, strings, Hashes and Arrays.
  Each expression 'node' of the AST is one of the following forms:
  
  AsciiMath::
  `asciimath` is converted to a an Array of expressions.
  An empty Array is converted to nil by the parser.
  A single element Array is unwrapped to just the element.
  +
  Sequences of expressions are returned as an Array of nodes.
  
  Parentheses::
  `lparen asciimath rparen` is converted to a Hash of the following form
  +
  [source]
  ----
  