anchor.diff:    (declare (ignore manager))
     (setf *guix-database* nil))
   
  -(defmethod manager-install ((manager guix-manager) output-list &optional profile)
  +(defmethod manager-install ((manager guix-manager) package-or-output-list
  +                            &optional profile)
     (run (append (list (path manager) "install")
  -               (mapcar (lambda (output)
  -                         (let ((package (parent-package output)))
  +               (mapcar (lambda (package-or-output)
  +                         (let ((package (if (guix-package-p package-or-output)
  +                                            package-or-output
  +                                            (parent-package package-or-output)))
  +                               (output (if (guix-package-output-p package-or-output)
  +                                            package-or-output
  +                                            ;; Default to first output, usually "out".
  +                                            (first (outputs package-or-output)))))
                              (format nil "~a@~a:~a"
                                      (name package)
                                      (version package)
                                      (name output))))
  -                       output-list)
  +                       package-or-output-list)
                  (when profile
                    (list (str:concat "--profile=" (namestring profile)))))))
   
  
positive.code:   (:accessor-name-transformer #'class*:name-identity)
    (:documentation "OS package outputs are meaningful mostly for functional
  package managers like Nix or Guix."))
  
  (detect-manager "guix" 'guix-manager)
  
  
negative.code:   (:export-accessor-names-p t)
    (:accessor-name-transformer #'class*:name-identity))
  
  (defun guix-package-p (object)
    (mopu:subclassp (class-of object) 'guix-package))
  
  (export-always 'expanded-output-p)
  (defun expanded-output-p (output)
    "Return nil if package OUTPUT location hasn't been computed."
  