anchor.diff:      ;; The other atoms are unchanged:
       ((atom form)     `(self-evaluating ,form))
       ;; Now we have a list.
  +    ((and (listp (first form))
  +          (eq 'cl:lambda (first (first form))))
  +     ;; ((cl:lambda …) …)
  +     (step-function-call form env))
  +    ((and (listp (first form))
  +          (eq 'lambda (first (first form))))
  +     ;; ((lambda …) …)
  +     (step-function-call form env))
  +    ((let ((somf (assoc (first form) *implementation-specific-special-operators*)))
  +       (and somf
  +            (progn (step-expression (funcall (cdr somf) form env) env)
  +                   t))))
       (t
        (case (first form)
  -
          ;; First we check the real CL special operators:
          ;; We map them to cl-stepper operators and step the mapped version.
          ((function quote)
  
positive.code: ;;;;LEGAL
  ;;;;    AGPL3
  ;;;;
  ;;;;    Copyright Pascal J. Bourguignon 2012 - 2021
  ;;;;
  ;;;;    This program is free software: you can redistribute it and/or modify
  ;;;;    it under the terms of the GNU Affero General Public License as published by
  
negative.code:              (did-step display-form results)
               (values-list results))))
      (case *step-mode*
        ((:run :function) (funcall thunk))
        (:trace  (with-parens *step-trace-output* (do-step)))
        (:step   (with-parens *step-trace-output*
                   (doagain
  