Re: Bus error

[Georg Bauhaus <bauhaus.rm.tsoh@maps.futureapps.de>]

Dmitry A. Kazakov wrote:
> On Fri, 29 Jun 2007 11:35:28 +0200, Duncan Sands wrote:
> 
>
>> in Ada 95 you could do
>>
>> 	X : T renames Factory;
> 
> Yes, you're right. It should be illegal. Semantically it is same as
>
>    X : Integer renames 1; -- Illegal

I don't think that renaming an object is the same as renaming
a number literal because the literal isn't declared anywhere.
Wheras I could say that a returned object is declared as part
of the function declaration.
 
 
>    function Very_Positive return Integer is
>    begin
>        return -1;
>    end Very_Positive;
> 
>    Oops : Positive renames Very_Positive; -- This is OK!

So is

  if 42 not in Boolean'pos(false) .. Boolean'pos(true) then
      raise Constraint_Error;
  end if;

Subtypes don't create new types in Ada. I wonder why you
keep pretending they do?

It is a mistake is to have predifined numeric types in a language
because this invites all kinds of assumptions about numeric types.