anchor.diff:  (defun compile-progn (body txt st pos names)
     (unless (null body)
       (with-gensyms (s p)
  -      (compile-form-in-progn
  +      (compile-wrapped-form
  +       #'progn-wrapper
          (first body)
          txt st pos s p names
          (compile-progn (rest body) txt s p names)))))
  
positive.code:      (if ,ok
           ,(or continuation `(values t ,result ,s ,p))
           ,failure)))
  
  (defun compile-wrapped-form (wrapper form text orig-state orig-position s p names continuation)
    (with-gensyms (ok)
  
negative.code:             ((stringp form) (wrap (compile-string form text s p) (gensym "R")))
              (t form))))))
  
  (defun compile-expression (exp names)
    (with-gensyms (text state position)
      (cond
  