Re: Conversions

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Bruno wrote:
> 
> I have a little problem with a function that "convert" a date, that is a
> record type, into a string. To do this I'm using "image" attribute how
> can you see in the following code
> 
> http://paste.ideaslabs.com/show/5KEJUGcDF
> 
> but when run the program and the function is executed a get an
> "constraint error". The compiler show me a message that say that the
> size is too long but I don't know what to do.

'Image for an integer type returns the shortest string necessary to represent 
the value, with ' ' added to the front for a positive value and '-' for a 
negative value.

Thus we can get

6   => " 6"
-6  => "-6"
10  => " 10"
-10 => "-10"

For your application (date image), 2-digit day and month numbers are likely; 
their 'Image will not fit in 2 characters.

You can save the 'Image and decide what to do with it:

declare
    Day_Image : constant String := Integer'Image (F.Dia);
begin
    if F.Dia < 10 then
       S (1) := '0';
       S (2) := Day_Image (Day_Image'Last);
    else
       S (1 .. 2) := Day_Image (Day_Image'Last - 1 .. Day_Image'Last);
    end if;
end;

You can also look at the operations in Ada.Text_IO.Integer_IO that write to a 
String parameter.

-- 
Jeff Carter
"We call your door-opening request a silly thing."
Monty Python & the Holy Grail
17