Initial data commit

Task/Stack/Oberon/stack-2.oberon

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+MODULE Stacks; (** AUTHOR ""; PURPOSE ""; *)
+
+IMPORT
+	Out := KernelLog;
+
+TYPE	
+	Object = OBJECT
+	END Object;
+	
+	Stack* = OBJECT
+	VAR
+		top-,capacity-: LONGINT;
+		pool: POINTER TO ARRAY OF Object;
+		
+		PROCEDURE & InitStack*(capacity: LONGINT);
+		BEGIN
+			SELF.capacity := capacity;
+			SELF.top := -1;
+			NEW(SELF.pool,capacity)
+		END InitStack;
+		
+		PROCEDURE Push*(a:Object);
+		BEGIN
+			INC(SELF.top);
+			ASSERT(SELF.top < SELF.capacity,100);
+			SELF.pool[SELF.top] := a
+		END Push;
+		
+		PROCEDURE Pop*(): Object;
+		VAR
+			r: Object;
+		BEGIN
+			ASSERT(SELF.top >= 0);
+			r := SELF.pool[SELF.top];
+			DEC(SELF.top);RETURN r
+		END Pop;
+		
+		PROCEDURE Top*(): Object;
+		BEGIN
+			ASSERT(SELF.top >= 0);
+			RETURN SELF.pool[SELF.top]
+		END Top;
+		
+		PROCEDURE IsEmpty*(): BOOLEAN;
+		BEGIN
+			RETURN SELF.top < 0
+		END IsEmpty;
+		
+	END Stack;
+	
+	BoxedInt = OBJECT
+	(Object)
+	VAR
+		val-: LONGINT;
+
+	PROCEDURE & InitBoxedInt*(CONST val: LONGINT);
+	BEGIN	
+		SELF.val := val
+	END InitBoxedInt;
+
+	END BoxedInt;
+
+	PROCEDURE Test*;
+	VAR
+		s: Stack;
+		bi: BoxedInt;
+		obj: Object;
+	BEGIN
+		NEW(s,10); (* A new stack of ten objects *)
+		NEW(bi,100);s.Push(bi);
+		NEW(bi,102);s.Push(bi);		
+		NEW(bi,104);s.Push(bi);
+		Out.Ln;
+		Out.String("Capacity:> ");Out.Int(s.capacity,0);Out.Ln;
+		Out.String("Size:> ");Out.Int(s.top + 1,0);Out.Ln;
+		obj := s.Pop(); obj := s.Pop();
+		WITH obj: BoxedInt DO
+			Out.String("obj:> ");Out.Int(obj.val,0);Out.Ln
+		ELSE
+			Out.String("Unknown object...");Out.Ln;
+		END (* with *)
+	END Test;
+END Stacks.