anchor.diff:  ----
   
   As seen previously, the `decorator` function is called only the first time and for every subsequent call the function reference
  -returned by the decorator is not re-computed but directly used as a contant.
  +returned by the decorator is not re-computed but directly used as a constant.
   
   
  -Parametrized decorators can be banged too :
  +Parametrized decorators can be banged too:
   
   [source,golo]
   ----
  
positive.code: function identity = |x| -> decorator(|x| -> x)(x)
  ----
  
  A banged decorator declared with the `@!` syntax :
  
  [source,golo]
  ----
  
negative.code: function identity = |x| -> x
  ----
  
  is expandend to:
  
  [source,golo]
  ----
  