Re: Optimizing Boundary Checks

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

Vinzent Hoefler wrote:

> As an example, currently
> 
> |x : My_Enum;
> |
> |for i in x'Range loop ...
> 
> doesn't work, you have to write
> 
> |for in in My_Enum'Range loop
> 
> each time. Is there any convincing explanation why it isn't allowed to
> use the actual type of a variable instead of the type itself? I can
> imagine situations (especially with subtypes) where it could be handy
> to use the variables' type instead of an explicit type specification.

Another example where getting the actual type could be useful:

procedure Foo (X, Y : Object'Class) is
begin
   if X in Y'Class then -- Illegal ín Ada
      ...

   [However the same effect could be achieved if Tag were comparable.]

declare
   Z : Y'Class; -- Steals discriminants and the tag
                -- of possibly limited Y

-- 
Regards,
Dmitry A. Kazakov
www.dmitry-kazakov.de