pdf

dbms.cl

@@ -1,11 +1,3 @@
-(defun hello () 
-  (format t "hello, wordl!"))
-
-
-
-(defun list_test () 
-  (getf (list :a 1 :b 2 :c 3) :a))
-
 (defvar *db* nil)
 
 (defun make-cd (title artist rating ripped)
@@ -47,4 +39,25 @@
 	#'(lambda (cd) (equal (getf cd :artist) artist))
 	*db*))
 
-(format *query-io* "hello~%")
+(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*)))