anchor.diff:         (%obj-getenv env name)))))
   
   (defun (setf environment-variable) (value name &optional env &key (overwrite t))
  +  "SETF ENVIRONMENT-VARIABLE sets the environment variable
  +identified by NAME to VALUE. Both NAME and VALUE can be either a
  +symbols or strings. Signals an error on failure."
     (let ((value (string value))
           (name (string name)))
       (etypecase env
  
positive.code:   "Creates symbolic LINK that points to TARGET.
  Returns the file-path of the link.
  
  Relative targets are resolved against the link.  Relative links
  are resolved against *DEFAULT-FILE-PATH-DEFAULTS*.
  
  Signals an error if TARGET does not exist, or LINK exists already."
  
negative.code: 
  (defun mapdir (function pathspec)
    "Applies function to each entry in directory designated by
  PATHSPEC in turn and returns a list of the results. Binds
  *DEFAULT-FILE-PATH-DEFAULTS* to the directory designated by
  pathspec round to function call.
  
  