Re: Prefix to 'ACCESS must either statically match... But why?

["Martin Krischik" <Martin.Krischik@T-Online.de>]

On Sat, 25 Jan 2003 14:31:17 +0000, Wojtek Narczynski wrote:

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> From: wojtek@power.com.pl (Wojtek Narczynski)
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> Subject: Prefix to 'ACCESS must either statically match... But why?
> Date: 25 Jan 2003 14:31:17 -0800
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> 
> Hello,
> 
> Could somebody please explain me why is this rule present? I find it
> very limting. Is this because AR2 bounds are not stored with the
> object?
> 
> Type Stream_Element_Array_access is access all Stream_Element_Array;
> 
> AR1 : aliased Stream_Element_Array := ( 2, 4, 5 );
> AR2 : aliased Stream_Element_Array ( 1 .. 3 ) := ( 2, 4, 5 );
> 
> AR1A : Stream_Element_Array_access := AR1'access;
> 
> -- Illegal
> AR2A : Stream_Element_Array_access := AR2'access;
> 
> 
> LRM:3.10.2(27), The nominal subtype of the prefix to 'ACCESS or
> 'UNCHECKED_ACCESS must either statically match the designated subtype
> of the expected type or the designated subtype must be discriminated
> and unconstrained, Continuing

Well I am a Ada-beginner myself so I might be wrong, but as far as I
understand strictly typed languages in general "Stream_Element_Array ( 1 .. 3 )" is a
new anonymous type which ist not a Stream_Element_Array anymore. A bit like typing

Type Stream_Element_Array_AR2 is new Stream_Element_Array ( 1 .. 3 );
AR2 : aliased Stream_Element_Array_AR2 := ( 2, 4, 5 );

Hope it helps

Martin

-- 
Martin Krischik
mailto://Martin@krischik.com
http://www.ada.krischik.com