DanielRM

;;; rips.lisp

;;; A simple database for CD rips

;;; by Daniel Rhodes-Mumby (DanielRM)

;;;

;;; Shamelessly adapted from Peter Seibel's "Practical Common Lisp"

;;;

;;; September 2008

;;;

;;; Function definitions are preceded by ';;' and an explanation of their purpose.

;;; Inline comments are preceded by ';'

;;;

;; Define the startup function and dependencies.

;; Also define the the save database function for completeness.

(defun startup ()

  (format t "~a" "Welcome to the Rips-Lisp CD rips database program.")

  ;say hello

 

  (defun db-load (filename)

    ;define the load database function

   

    (with-open-file (in filename)

      (with-standard-io-syntax

        (setf *db-rips* (read in)))))

        ;this clobbers the working database

 

  (defun db-save (filename)

    ;define the save database function

   

    (with-open-file (out filename

                         :direction :output

                         :if-exists :supersede)

      ;overwrite an existing file - if the user's smart they'll avoid doing this without thinking

     

      (with-standard-io-syntax

        (print *db-rips* out))))

        ;let the user know the contents of the database

 

  (defvar *db-rips* nil))

  ;define the database variable

;;;

;; Define the function for making CD records.

(defun cd-create (artist title priority ripped-mp3 ripped-ogg)

  (list :artist artist :title title :priority priority :ripped-mp3 ripped-mp3 :ripped-ogg ripped-ogg))

;;;

;; Define the function for showing the database.

(defun db-dump (&optional (db *db-rips*))

  (dolist (cd db)

    (format t "~{~a:~20t~a~%~}~%" cd)))

    ;I quite honestly have no idea how most of this format call works.

;;;

;; Define record manipulation functions.

(defun cd-add (cd)

  (push cd *db-rips*))

  ;push the record on to the database variable.

;;;

;; Define a prompt reader.

(defun prompt-read (prompt)

  (format *query-io* "~a: " prompt)

  (force-output *query-io*)

  (read-line *query-io*))

;;;

;; Prompt for the CD now.

(defun cd-prompt ()

  (cd-create

    (prompt-read "Artist")

    (prompt-read "Album name")

    (or (parse-integer (prompt-read "Priority") :junk-allowed t) 0)

    (y-or-n-p "Ripped to MP3 (you dirty capitalist) [y/n]: ")

    (y-or-n-p "Ripped to OGG (freedom uber alles!) [y/n]: ")))

;;;

;; Continually prompt.

(defun cd-prompter ()

  (loop (cd-add (cd-prompt))

        (if (not (y-or-n-p "Another? [y/n]: "))

        ;loop around until the user doesn't want to add another CD

          (return))))

;;;

;; Write a selector function for queries.

(defun select (selector-function)

  (db-dump (remove-if-not selector-function *db-rips*)))

;;;

;; Define a general selection category function.

(defun where (&key artist title priority (ripped-mp3 nil ripped-mp3-p) (ripped-ogg nil ripped-ogg-p))

  #'(lambda (cd)

      (and

        (if artist      (equal (getf cd :artist) artist) t)

        (if title       (equal (getf cd :title) title) t)

        (if priority    (equal (getf cd :priority) priority) t)

        (if ripped-mp3-p (equal (getf cd :ripped-mp3) ripped-mp3) t)

        (if ripped-ogg-p (equal (getf cd :ripped-ogg) ripped-ogg) t))))

;;; Actually run the startup function.

(startup)