anchor.diff:  
   (defun symbolp (x)
     "Tests if variable points to itself."
  -  (and (atom x)
  -	   (not (symbol-function x))
  -	   (eq x (symbol-value x))))
  +  (if (and (atom x)
  +		   (not (= 0 (length (symbol-name x)))))
  +	  t))
   
   (defun variablep (x)
     (and (atom x)
   	   (not (or (stringp x)
   				(numberp x)))))
  +; XXX ARRAYP ?
   
   (defun keywordp (x)
     "Tests if symbol is in the keyword package."
  
positive.code: (define-test "NOT works with T"
    ((not t))
    nil)
  
negative.code: ;;;;; TRE environment
  ;;;;; Copyright (c) 2005-2006,2008-2009 Sven Klose <pixel@copei.de>
  ;;;;;
  ;;;;; Predicate functions
  
  