Re: [Q] Returning Strings From A Function

[mheaney@ni.net (Matthew Heaney)]

In article <33478738.2129057@news.demon.co.uk>, john@assen.demon.co.uk
(John McCabe) wrote:

>
>>John, it is still very difficult to understand what you are asking for.
>>Your code above makes perfect sense if you want File_Name to be 12 characters
>>long, and of course the assignment will check for 12 characters.
>
>Exactly - but I want the assignment to check for <=12 characters.

In Ada 83, you can just assign the function return value to a (constant)
object, and then do whatever you want with it (including assigning it to a
fixed-length string).  For example,

subtype Name_String is String (1 .. 12);

procedure Get_Name (Name : out Name_String) is

   The_Name : constant String := Text_IO.Name (The_File);

   Pad_Length : constant Natural := Name'Length - The_Name'Length;

   Pad : constant String (1 .. Pad_Length) := (others => ' ');

begin

   Name := The_Name & Pad;

end;

A hipper technique is to use a string buffer, as follows:

subtype Name_Length_Range is Natural range 0 .. 12;

type Name_Buffer (Length : Name_Length_Range := 0) is
   record
      Name : String (1 .. Length);
   end record;

procedure Get_Name (Name : out Name_Buffer) is

   The_Name : constant String := Text_IO.Name (The_File);

begin

   Name := (The_Name'Length, The_Name);

end;

Hope that helps,

Matt

--------------------------------------------------------------------
Matthew Heaney
Software Development Consultant
<mailto:matthew_heaney@acm.org>
(818) 985-1271