Another update from ingydotnet^djgoku

Task/Power-set/Ada/power-set-1.ada

@@ -0,0 +1,10 @@
+package Power_Set is
+
+   type Set is array  (Positive range <>) of Positive;
+   Empty_Set: Set(1 .. 0);
+
+   generic
+      with procedure Visit(S: Set);
+   procedure All_Subsets(S: Set); -- calles Visit once for each subset of S
+
+end Power_Set;

Task/Power-set/Ada/power-set-2.ada

@@ -0,0 +1,20 @@
+package body Power_Set is
+
+   procedure All_Subsets(S: Set) is
+
+      procedure Visit_Sets(Unmarked: Set; Marked: Set) is
+	 Tail: Set      := Unmarked(Unmarked'First+1 .. Unmarked'Last);
+      begin
+	 if Unmarked = Empty_Set then
+	    Visit(Marked);
+	 else
+	    Visit_Sets(Tail, Marked & Unmarked(Unmarked'First));
+	    Visit_Sets(Tail, Marked);
+	 end if;
+      end Visit_Sets;
+
+   begin
+      Visit_Sets(S, Empty_Set);
+   end All_Subsets;
+
+end Power_Set;

Task/Power-set/Ada/power-set-3.ada

@@ -0,0 +1,28 @@
+with Ada.Text_IO, Ada.Command_Line, Power_Set;
+
+procedure Print_Power_Set is
+
+   procedure Print_Set(Items: Power_Set.Set) is
+      First: Boolean := True;
+   begin
+      Ada.Text_IO.Put("{ ");
+      for Item of Items loop
+	 if First then
+	    First := False; -- no comma needed
+	 else
+	    Ada.Text_IO.Put(", "); -- comma, to separate the items
+	 end if;
+	 Ada.Text_IO.Put(Ada.Command_Line.Argument(Item));
+      end loop;
+      Ada.Text_IO.Put_Line(" }");
+   end Print_Set;
+
+   procedure Print_All_Subsets is new Power_Set.All_Subsets(Print_Set);
+
+   Set: Power_Set.Set(1 .. Ada.Command_Line.Argument_Count);
+begin
+   for I in Set'Range loop -- initialize set
+      Set(I) := I;
+   end loop;
+   Print_All_Subsets(Set); -- do the work
+end;

Task/Power-set/Ada/power-set.ada

@@ -1,42 +0,0 @@
-with Ada.Text_IO, Ada.Command_Line;
-
-procedure Power_Set is
-
-   type List is array  (Positive range <>) of Positive;
-   Empty: List(1 .. 0);
-
-   procedure Print_All_Subsets(Set: List; Printable: List:= Empty) is
-	
-      procedure Print_Set(Items: List) is
-	 First: Boolean := True;
-      begin
-	 Ada.Text_IO.Put("{ ");
-	 for Item of Items loop
-	    if First then
-	       First := False; -- no comma needed
-	    else
-	       Ada.Text_IO.Put(", "); -- comma, to separate the items
-	    end if;
-	    Ada.Text_IO.Put(Ada.Command_Line.Argument(Item));
-	 end loop;
-	 Ada.Text_IO.Put_Line(" }");
-      end Print_Set;
-
-      Tail: List := Set(Set'First+1 .. Set'Last);
-
-   begin
-      if Set = Empty then
-	 Print_Set(Printable);
-      else
-	 Print_All_Subsets(Tail, Printable & Set(Set'First));
-	 Print_All_Subsets(Tail, Printable);
-      end if;
-   end Print_All_Subsets;
-
-   Set: List(1 .. Ada.Command_Line.Argument_Count);
-begin
-   for I in Set'Range loop -- initialize set
-      Set(I) := I;
-   end loop;
-   Print_All_Subsets(Set); -- do the work
-end Power_Set;