(defpackage asdf-list-packages
  (:use :cl :asdf)
  (:export #:*own-packages*))
(in-package asdf-list-packages)

(defvar *dependency-packages* '())

(defvar *own-packages* '()
  "Created packages of the asdf-list-packages system.

This list is populated after the asdf-list-packages system is loaded.")

(defsystem "asdf-list-packages"
  ;; system/component metadata
  :description "Automatically list created packages."
  :long-description "This demonstrates how to list the created
packages of a system."

  ;; dependencies; installed automatically by quicklisp
  :depends-on (alexandria)

  ;; files loaded by asdf for system asdf-list-packages
  :components ((:file "main"
                :description "This is the main file, it has one
package called MY-PACKAGE."))
  :perform (prepare-op :after (o c)
                       (setq *dependency-packages* (list-all-packages)))
  :perform (load-op :after (o c)
                    (setq *own-packages*
                      (remove-if (lambda (x) (member x *dependency-packages*))
                                 (list-all-packages)))))