June 2018 Update

Task/Priority-queue/XLISP/priority-queue-1.xlisp

@@ -0,0 +1,35 @@
+(define-class priority-queue
+	(instance-variables queue lowest-priority most-urgent) )
+
+(define-method (priority-queue 'initialize limit)
+	(defun setup (x)
+		(vector-set! queue x nil)
+		(if (< x limit)
+			(setup (+ x 1)) ) )
+	(setq lowest-priority limit)
+	(setq most-urgent limit)
+	(setq queue (make-vector (+ limit 1)))
+	(setup 0)
+	self )
+
+(define-method (priority-queue 'push item priority)
+	(if (and (integerp priority) (>= priority 0) (<= priority lowest-priority))
+		(progn
+			(setq most-urgent (min priority most-urgent))
+			(vector-set! queue priority (nconc (vector-ref queue priority) (cons item nil))) ) ) )
+
+(define-method (priority-queue 'pop)
+	(defun find-next (q)
+		(if (or (= q lowest-priority) (not (null (vector-ref queue q))))
+			q
+			(find-next (+ q 1)) ) )
+	(define item (car (vector-ref queue most-urgent)))
+	(vector-set! queue most-urgent (cdr (vector-ref queue most-urgent)))
+	(setq most-urgent (find-next most-urgent))
+	item )
+
+(define-method (priority-queue 'peek)
+	(car (vector-ref queue most-urgent)) )
+
+(define-method (priority-queue 'emptyp)
+	(and (= most-urgent lowest-priority) (null (vector-ref queue most-urgent))) )

Task/Priority-queue/XLISP/priority-queue-10.xlisp

@@ -0,0 +1,3 @@
+[13] (pq 'pop)
+
+()

Task/Priority-queue/XLISP/priority-queue-2.xlisp

@@ -0,0 +1,7 @@
+(define pq (priority-queue 'new 5))
+
+(pq 'push "Clear drains" 3)
+(pq 'push "Feed cat" 4)
+(pq 'push "Make tea" 5)
+(pq 'push "Solve RC tasks" 1)
+(pq 'push "Tax return" 2)

Task/Priority-queue/XLISP/priority-queue-3.xlisp

@@ -0,0 +1,6 @@
+[1] (pq 'pop)
+
+"Solve RC tasks"
+[2] (pq 'pop)
+
+"Tax return"

Task/Priority-queue/XLISP/priority-queue-4.xlisp

@@ -0,0 +1,3 @@
+[3] (pq 'push "Answer emails" 4)
+
+("Feed cat" "Answer emails")

Task/Priority-queue/XLISP/priority-queue-5.xlisp

@@ -0,0 +1,3 @@
+[4] (pq 'push "Weed garden" 17)
+
+()

Task/Priority-queue/XLISP/priority-queue-6.xlisp

@@ -0,0 +1,3 @@
+[5] (pq 'emptyp)
+
+()

Task/Priority-queue/XLISP/priority-queue-7.xlisp

@@ -0,0 +1,3 @@
+[6] (pq 'peek)
+
+"Clear drains"

Task/Priority-queue/XLISP/priority-queue-8.xlisp

@@ -0,0 +1,8 @@
+[7] (pq 'show)
+
+Object is #<Object:PRIORITY-QUEUE #x4e2cba8>, Class is #<Class:PRIORITY-QUEUE #x4e254c8>
+Instance variables:
+  QUEUE = #(() () () ("Clear drains") ("Feed cat" "Answer emails") ("Make tea"))
+  LOWEST-PRIORITY = 5
+  MOST-URGENT = 3
+#<Object:PRIORITY-QUEUE #x4e2cba8>

Task/Priority-queue/XLISP/priority-queue-9.xlisp

@@ -0,0 +1,15 @@
+[8] (pq 'pop)
+
+"Clear drains"
+[9] (pq 'pop)
+
+"Feed cat"
+[10] (pq 'pop)
+
+"Answer emails"
+[11] (pq 'pop)
+
+"Make tea"
+[12] (pq 'emptyp)
+
+#T