anchor.diff:  ----
   <1> Note the usage of parentheses to surround an expression to apply the unary minus to that surrounded expression.
   
  -In terms of unary arithmetics operators, the ++++ (increment) and +--+ (decrement) operators are available, 
  +In terms of unary arithmetic operators, the ++++ (increment) and +--+ (decrement) operators are available, 
   both in prefix and postfix notation:
   
   [source,groovy]
  
positive.code: | greater than or equal
  |====
  
  These operators into action in simple number comparisons:
  
  [source,groovy]
  ----
  
negative.code: |
  
  | +-+
  | subtraction
  |
  
  | +*+
  