; your code goes here
;; PCL chapter 3
(defvar *db* nil)
(defun add-record (cd) (push cd *db*))
(defun dump-db()
(dolist (cd *db*)
(format t "~{~a:~10t~a~%~}~%" cd)))
(defun prompt-read (prompt)
(format *query-io* "~a: " prompt)
(force-output *query-io*)
(read-line *query-io*))
(defun prompt-for-cd ()
(make-cd
(prompt-read "Title")
(prompt-read "Artist")
(or
(parse-integer (prompt-read "Rating") :junk-allowed t)
0)
(y-or-n-p "Ripped [y/n]: ")))
(defun add-cds()
(loop (add-record (prompt-for-cd))
(if (not (y-or-n-p "Another? [y/n]: ")) (return))))
(defun save-db (filename)
(with-open-file (out filename
:direction :output
:if-exists :supersede)
(with-standard-io-syntax
(print *db* out))))
(defun load-db (filename)
(with-open-file (in filename)
(with-standard-io-syntax
(setf *db* (read in)))))
(defun select (selector-fn)
(remove-if-not selector-fn *db*))
(defmacro where (&rest clauses)
`#'(lambda (cd) (and ,@(make-comparison-list clauses))))
(defun make-comparison-list (fields)
(loop while fields
collecting (make-comparison-expr (pop fields) (pop fields))))
(defun make-comparison-expr (field value)
`(equal (getf cd ,field) ,value))
(defun update (selector-fn &key title artist rating (ripped nil ripped-p))
(setf *db*
(mapcar
#'(lambda (row)
(when (funcall selector-fn row)
(if title (setf (getf row :title) title))
(if artist (setf (getf row :artist) artist))
(if rating (setf (getf row :rating) rating))
(if ripped-p (setf (getf row :ripped) ripped)))
row) *db*)))
(defun delete-rows (selector-fn)
(setf *db* (remove-if selector-fn *db*)))
(defun make-cd (title artist rating ripped)
(list :title title :artist artist :rating rating :ripped ripped))