Re: GNAT.Serial_Communications

[tonyg <tonythegair@gmail.com>]

On Apr 15, 7:01 pm, Jeffrey Carter
<spam.jrcarter....@spam.not.acm.org> wrote:
> On 04/15/2011 09:32 AM, tonyg wrote:
>
> >        for count in
> > 1..Ada.Streams.Stream_Element_Offset(The_String'Length) loop
> >           Return_Value(count) :=
> > character'pos(The_String(Integer(count)));
>
> You assume that The_String'First = 1, which will not be the case if you pass a
> slice with a different lower bound. However, that will cause Constraint_Error
> (unless you have turned off this check), which does not seem to be the problem.
>
> >        Return Return_Value(1..The_String'Length);
>
> I see no reason for the slice.
>
> You should be able to replace the body of String_To_Stream with a simple
> Unchecked_Conversion:
>
> with Ada.Streams;
> with Ada.Text_IO;
> with Ada.Unchecked_Conversion;
>
> procedure Stream_Convert is
>     subtype String3 is String (1 .. 3);
>
>     From : constant String3 := "abc";
>
>     subtype Stream3 is Ada.Streams.Stream_Element_Array (1 .. From'Length);
>
>     function To_Stream is new Ada.Unchecked_Conversion (Source => String3,
> Target => Stream3);
>
>     To : Stream3;
> begin -- Stream_Convert
>     To := To_Stream (From);
>
>     Output : for I in To'range loop
>        Ada.Text_IO.Put (Item => To (I)'Img);
>     end loop Output;
> end Stream_Convert;
>
> --
> Jeff Carter
> "Unix and C are the ultimate computer viruses."
> Richard Gabriel
> 99

I did that because I got a bit paranoid with the way ada handles
strings after finding out something new in the way its handles them. I
used to think that a slice's indexes changed when it went through a
procedure or functions paramaters but came unstuck by it. Thanks for
the code, I'll give it a try once I get this naughty serial port
sorted.