anchor.diff:  
      {=range} applies _parser_ and, if it succeeds, applies _predicate_ to
      _from_, its results and _to_. {=range} succeeds with the result of
  -   _parser_ if _predicate_ is _true_ and fails otherwise. Fails if the
  -   input is empty."
  +   _parser_ if _predicate_ is _true_ and fails otherwise."
     (=let* ((char parser))
       (if (funcall predicate from char to)
   	(=result char) 
  
positive.code:   "*Description:*
  
     {=item} consumes the next item and succeeds with that item as its
     result unless the input is empty. Fails if the input is empty."
    (lambda (input)
      (unless (input-empty-p input)
        (list (cons (input-first input)
  
negative.code: 
     {=not} consumes the next item and succeeds with that item as its
     result if _parser_ would fail. E.g. it negates _parser_. Note that
     _parser_ is not actually applied to the input."
    (=if parser (=fail) (=item)))
  
  (defun =prog1 (parser &rest parsers)
  