Pool Specific Access Types?

["Mr.Clueless" <chris@dont.spam.me>]

Alright...I'm creating an access type like this...

type Number;

type Numb_pnt is access Number;

type Number is
       record
	  The_Numb: Integer;
	   Next: Numb_pt;
	end record;
	
	N: Numb_pnt;

Now I know I got that part right...but I'm running into a problem in
reading and assigning  numbers (or any other kind of data) from/to the
linked list.

For example, I'll assign a new value from a variable like this...

	N := new Number'(<variable>, N);

which seems to work alright.  But then when I try to read from it using a
procedure such as...

	function Sum(List: Cell_Ptr) return Integer is
	   Local: Cell_Ptr := List; S: Integer := 0;
	begin
		while Local /= null loop
		  S := S + Local.Value; Local := Local.Next;
		 end loop;
		return S;
	end Sum;

I get an error in s-valuns at line 85.  Note I'm using the above code
segment that I found in  the Barnes book. This is a Constraint Error that
pops up at runtime and terminates the program. I suspect I'm not passing
data to or reading data from the List correctly, but I'm following the
examples in the book by wrote.

Any advice would help. Note, I am using Ada.Text_IO so as to pull the
Integers in off a text  string entered by the user at runtime.

Thanks.

Clueless. 
chris@dont.spam.me