September 2017 Update

Task/Priority-queue/Zkl/priority-queue-1.zkl

@@ -0,0 +1,20 @@
+class PQ{
+   fcn init(numLevels=10){  // 0..numLevels, bigger # == lower priorty
+      var [const] queue=(1).pump(numLevels+1,List.createLong(numLevels).write,L().copy);
+   }
+   fcn add(item,priorty){ queue[priorty].append(item); }
+   fcn peek{ if(q:=queue.filter1()) return(q[-1]);   Void }// -->Void if empty
+   fcn pop { if(q:=queue.filter1()) return(q.pop()); Void }// -->Void if empty
+   var [private] state=L();
+   fcn [private] next{ // iterate
+      qi,ii:=state;
+      foreach n in ([qi..queue.len()-1]){
+         q:=queue[n];
+	 if(ii>=q.len()) ii=0;
+	 else{ state.clear().append(n,ii+1); return(q[ii]) }
+      }
+      Void.Stop
+   }
+   fcn walker{ state.clear().append(0,0); Walker(next) } // iterator front end
+   fcn toString{ "PQ(%d) items".fmt(queue.reduce(fcn(sum,q){ sum+q.len() },0)) }
+}

Task/Priority-queue/Zkl/priority-queue-2.zkl

@@ -0,0 +1,13 @@
+pq:=PQ();
+foreach x in
+      (T("Clear drains",3, "Feed cat",4, "Make tea",5, "Solve RC tasks",1, "Tax return",2,
+         "Clean room",10,"Wash cat",10)){
+   pq.add(x,__xWalker.next())
+}
+pq.println();
+println("Number 1 thing to do: ",pq.peek());
+println("Top 2 things to do: ",pq.walker().walk(2));
+println("Do this next year: ",pq.walker().walk()[-1]);
+println("ToDo list:");
+foreach item in (pq){ item.println() }
+pq.println();