anchor.diff:  (define-test "NOT works with T"
     ((not t))
     nil)
  +
  +(define-test "KEYWORDP recognizes keyword-packaged symbols"
  +  ((keywordp :lisp))
  +  t)
  +
  +(define-test "KEYWORDP works with standard symbols"
  +  ((keywordp 'lisp))
  +  nil)
  
positive.code: ;;;;; TRE environment
  ;;;;; Copyright (c) 2005-2006,2008 Sven Klose <pixel@copei.de>
  ;;;;;
  ;;;;; Predicate functions
  
  
negative.code: 
  (defun symbolp (x)
    "Tests if variable points to itself."
    (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."
  