How to check class type ?

[DrPi <314@drpi.fr>]

Hi,

I have the following declarations (just for the example) :

type Root is tagged null record;
type Root_Ptr is access all Root'Class;

type Leaf1 is new Root with null record;
type Leaf1_Ptr is access all Leaf1'Class;

type Leaf2 is new Root with null record;
type Leaf2_Ptr is access all Leaf2'Class;


To check if a variable is of type Leaf1_Ptr or Leaf2_Ptr, I do :
if var'Tag = Leaf1'Tag then
    ...
elsif var'Tag = Leaf2'Tag then
    ...
end if;

It works. But is this correct ? Should the test be done differently to 
suit Ada coding style ?

Nicolas