(defun component-names (system) (mapcar (lambda (system) (cond ((typep system 'asdf:system) (asdf:component-name system)) ((typep system 'string) system) ((typep sysetm 'symbol) (string-downcase system)) (t (error "Unexpected type ~S for system: ~S" (type-of system) system)))) (asdf:component-depends-on 'asdf:load-op system))) doesn't work either.