anchor.diff:                           #-(or Allegro LispWorks CMU CLISP)
                            (error "Unsupported implementation."))))
   
  -(defun directoryp (path)
  -  #+(or Allegro Lispworks CMU)
  -  (probe-file path)
  -  #+CLISP
  -  (lisp:probe-directory path)
  -  #-(or Allegro LispWorks CMU CLISP)
  -  (error "No implementation for DIRECTORYP"))
  -
   (defun mkdir (path)
     #+CMU
     (unix:unix-mkdir
  
positive.code: ;;; File: defsys.lisp
  ;;; Description: System definition file for LISA project.
  ;;;
  ;;; $Id: defsys.lisp,v 1.21 2001/03/05 16:35:17 youngde Exp $
  
  (in-package :user)
  
  
negative.code:   #+CLISP
    (lisp:make-dir path))
    
  ;;; Make sure the binary directory structure exists, creating it if
  ;;; necessary...
  
  (let ((dirlist '("packages" "engine" "utils")))
    (unless (directory *lisa-binary-pathname*)
      (mkdir *lisa-binary-pathname*))
    (dolist (dir dirlist)
      (let ((path (make-pathname
                   :directory (append (pathname-directory
                                       *lisa-binary-pathname*)
                                      `(,dir)))))
        (unless (directory path)
          (mkdir path)))))
  
  #+CMU
  