Re: newbie problem

[Olivier Scalbert <olivier.scalbert@algosyn.com>]

Martin wrote:
>> Problem 1: it does not compile !
>> adasound.ads:23:10: completion of nonlimited type cannot be limited
>> adasound.ads:23:10: component "File_Type" of type "Als_File_T" has
>> limited type
> 
> Store an 'access' to the limited type.
> 
>> Problem 2: how to avoid the first "with Sequential_Io;" ?
> 
> private with Ada.Sequential_IO;  -- I always prefer the
>                                  -- Ada. prefix just to be clear
>                                  -- it's a standard unit to any
>                                  -- 'casual' reader
> 
> Cheers
> -- Martin

Thanks Martin,

I have modified the specification and it compiles now:

private with Ada.Sequential_Io;

package adasound is

     type Amplitude_T is new Float;
     type Frequency_T is new Float;
     type Time_T      is new Float;

     type Stereo_Amplitude_T is record
         Left : Amplitude_T;
         Right: Amplitude_T;
     end record;

     type Als_File_T is private;

     function  Als_Create(File_Name: String) return Als_File_T;
     procedure Als_Write(Als_File: Als_File_T; Stereo_Amplitude: 
Stereo_Amplitude_T);
     procedure Als_Close(Als_File: Als_File_T);

private
     package Stereo_Amplitude_Io is new Ada.Sequential_Io 
(Stereo_Amplitude_T);

     type Als_File_T is record
         File_Type: access Stereo_Amplitude_Io.File_Type;
         -- perhaps more stuff later
     end record;

end adasound;


How can implement the Als_Create function ?
Here is my code, but it does not compile !

package body adasound is

function Als_Create(File_Name: String) return Als_File_T is
     Result : Als_File_T;
     File: Stereo_Amplitude_Io.File_Type; -- Error !!!
begin
     Stereo_Amplitude_Io.Create(File, Stereo_Amplitude_Io.Out_File, 
File_Name);
     Result.File_Type := File; -- Line 10 Error !!!
     return Result;
end Als_Create;
...

gcc-4.3 -c adasound.adb
adasound.adb:10:22: left hand of assignment must not be limited type


Olivier.