```common lisp
;;;; grok-arch-hexagonal.asd

;;; The MIT License (MIT)
;;;
;;; Copyright (c) 2016 Michael J. Forster
;;;
;;; Permission is hereby granted, free of charge, to any person obtaining a copy
;;; of this software and associated documentation files (the "Software"), to deal
;;; in the Software without restriction, including without limitation the rights
;;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;;; copies of the Software, and to permit persons to whom the Software is
;;; furnished to do so, subject to the following conditions:
;;;
;;; The above copyright notice and this permission notice shall be included in all
;;; copies or substantial portions of the Software.
;;;
;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;;; SOFTWARE.

(asdf:defsystem #:grok-arch-hexagonal
  :description "Grokking Alistair Cockburn's Hexagonal Architecture"
  :author "Michael J. Forster <mike@forsterfamily.ca>"
  :license "MIT"
  :depends-on (#:alexandria
               #:lisp-unit)
  :serial t
  :components ((:file "package")
               (:file "grok-arch-hexagonal")))

```

Add system dependency on wu-decimal
user
```common lisp
;;;; grok-arch-hexagonal.asd

;;; The MIT License (MIT)
;;;
;;; Copyright (c) 2016 Michael J. Forster
;;;
;;; Permission is hereby granted, free of charge, to any person obtaining a copy
;;; of this software and associated documentation files (the "Software"), to deal
;;; in the Software without restriction, including without limitation the rights
;;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;;; copies of the Software, and to permit persons to whom the Software is
;;; furnished to do so, subject to the following conditions:
;;;
;;; The above copyright notice and this permission notice shall be included in all
;;; copies or substantial portions of the Software.
;;;
;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;;; SOFTWARE.

(asdf:defsystem #:grok-arch-hexagonal
  :description "Grokking Alistair Cockburn's Hexagonal Architecture"
  :author "Michael J. Forster <mike@forsterfamily.ca>"
  :license "MIT"
  :depends-on (#:alexandria
               #:wu-decimal
               #:lisp-unit)
  :serial t
  :components ((:file "package")
               (:file "grok-arch-hexagonal")))

```
assistant