Initial data commit

Task/Priority-queue/M2000-Interpreter/priority-queue-5.m2000

@@ -0,0 +1,100 @@
+form 80, 42
+Module OrdrerQueue (filename$)  {
+      // f=-2  or use empty filename for screen
+      open filename$ for output as #f
+      zz=list
+      pq=List
+      flush
+      // subs can read from module's stack
+      println("Add items to pq queue")
+      Data 4 ,"Feed cat",5 , "Make tea", 3, "Clear drains",1 , "Solve RC tasks"
+      AddItems(pq)
+      println("Add items to zz queue")
+      AddItems(zz, 2 , "Tax return", 1 ,"Solve RC tasks#2")
+      println("Peek top from zz queue")
+      PeekTop(zz)  // Solve RC tasks#2
+      println("Merge two priority lists")
+      merge(pq, zz, false)
+      println("Peek top from pq queue")
+      PeekTop(pq)  // Solve RC tasks
+      println("Add items to pq queue")
+      AddItems(pq, 1 ,"Solve RC tasks#3")
+      println("Peek top from pq queue")
+      PeekTop(pq)  // Solve RC tasks
+      println("Pop one from pq until empty queue")
+      while len(pq)>0
+            PopOne(pq)
+      end while
+      println("Pop one from zz until empty queue")
+      while len(zz)>0
+            PopOne(zz)
+      end while
+      close #f
+      sub AddItems(pq)
+            local s, z
+            while not empty
+                  read z
+                  if not exist(pq, z) then s=stack:append pq, z:=s else s=eval(pq)
+                  read what$: stack s {data what$}
+                  stack new {println( "add item",z,what$)}
+            end while
+            sort descending pq as number
+            Println()
+      end sub
+      sub merge(pq, qp, emptyqueue)
+            local needsort=false
+            local kqp=each(qp, -1, 1), k$, t, p
+            while kqp
+                  t=eval(kqp)
+                  k$= eval$(kqp!)
+                  if not exist(pq, eval$(kqp!)) then
+                        p=stack
+                        append pq, val(eval$(kqp!)):=p
+                        needsort=true
+                  else
+                        p=eval(pq)
+                  end if
+                  stack p {
+                        if emptyqueue then
+                              data !t
+                              delete qp,eval$(kqp!)
+                        else
+                              data !stack(t)
+                        end if
+                  }
+            end while
+            if needsort then sort descending pq as number
+      end sub
+      sub PeekTop(pq)
+            Local k=len(pq)
+            if k=0 then exit sub
+            k=val(eval$(pq, k-1))
+            if exist(pq, k) then local s=eval(pq): println( k,stackitem$(s, 1))
+      End sub
+      Sub PopOne(pq)
+            Local k=len(pq)
+            if k<0 then exit sub
+            k=val(eval$(pq, k-1))
+            if exist(pq, k) then
+                  local s=eval(pq)
+                  println( k,stackitem$(s, 1))
+                  if len(s)=1 then
+                        delete pq, k
+                  else
+                        stack s {drop}
+                  end if
+            end if
+       end sub
+       Sub println()
+             if empty then print #f, "": exit sub
+             while not empty
+                  if islet then print #f, letter$;
+                  if empty else print #f, " ";
+                  if isnum then print #f,  number;
+                  if empty else print #f, " ";
+             end while
+             if f=-2 and  pos=0 then exit sub
+             print #f, ""
+       end sub
+}	
+OrdrerQueue ""