error.lisp

CL-USER> *h*
The variable *H* is unbound.
   [Condition of type UNBOUND-VARIABLE]
; Evaluation aborted.
CL-USER> 

hello.asd

(defpackage :hello-system (:use :asdf :cl))
(in-package :hello-system)

(defsystem hello
  :name "hello"
  :author ""
  :version ""
  :maintainer ""
  :licence ""
  :description ""
  :long-description ""
  :components
  ((:file "packages")
   (:file "string-of-hello-world" :depends-on ("packages"))
   ;; body-of-hello-world.lisp は packages.lisp と string-of-hello-world.lisp に依存している
   (:file "body-of-hello-world" :depends-on ("packages" "string-of-hello-world"))))

test-of-hello-system.lisp

CL-USER> (asdf:operate 'asdf:load-op :hello)
; loading system definition from /home/cametan/hello/hello.asd into
; #<PACKAGE "ASDF0">
; registering #<SYSTEM HELLO {B4E73E1}> as HELLO
NIL
CL-USER> (use-package :hello)
T
CL-USER> (hello-world)
Hello, World!
"Hello, World!"
CL-USER> (symbol-package 'hello-world)
#<PACKAGE "HELLO">
CL-USER>