carnifex/dbms.cl
Gregory Tertyshny 0bda960f26 pdf
2017-05-30 16:25:12 +03:00

63 lines
1.6 KiB
Common Lisp

(defvar *db* nil)
(defun make-cd (title artist rating ripped)
(list :title title :artist artist :rating rating :ripped ripped))
(defun add-record (cd)
(push cd *db*))
(defun dump-db ()
(dolist (cd *db*)
(format t "~{~a:~9t~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 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-by-artist (artist)
(remove-if-not
#'(lambda (cd) (equal (getf cd :artist) artist))
*db*))
(defun select (selector-fn)
(remove-if-not selector-fn *db*))
(defun where (&key artist title rating (ripped nil ripped-p))
#'(lambda (cd)
(and
(if title (equal (getf cd :title) title) t)
(if artist (equal (getf cd :artist) artist) t)
(if rating (equal (getf cd :rating) rating) t)
(if ripped-p (equal (getf cd :ripped) ripped) t))))
(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*)))