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Newsgroups: comp.lang.ada
Subject: Re: What does this code mean?
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Date: Wed, 07 Jan 2015 21:37:08 -0700
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Date: 2015-01-07T21:37:08-07:00
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On 07-Jan-15 20:53, John Smith wrote:
>
> My question is why is this code written this way?
>  Is it just plain wrong or am I missing some concept that the author(s)
> tried to get across that I'm missing?
>

I think it's wrong -- the "package I_IO is new Ada (Short);" is syntax 
for instantiating a generic package... noticing the space-comma, I think 
there might have been a transcription error -- it is likely this is what 
was meant:


    With Ada.Text_IO;
    procedure Convert_Checked is
       type Short is range -128 .. +127;
       type Byte is mod 256;

       package T_IO renames Ada.Text_IO;
       package I_IO is new Ada.Text_IO.Integer_IO (Short);
       package M_IO is new Ada.Text_IO.Modular_IO (Byte);

       A : Short := -1;
       B : Byte;
    begin
       B := Byte (A); -- range check will lead to Constraint_Error

       T_IO.Put("A = ");
       I_IO.Put(Item  => A,
                Width => 5,
                Base  => 10);
       T_IO.Put(", B = ");
       M_IO.Put(Item  => B,
                Width => 5,
                Base  => 10);
    end Convert_Checked;