Re: How to extract range from array

[Martin Krischik <krischik@users.sourceforge.net>]

Maciej Sobczak wrote:

> Martin Krischik wrote:
> 
>> Read:
>> 
>> http://en.wikibooks.org/wiki/Ada_Programming/Types/array#Array_Attributes
> 
> subtype My_Range is Integer range My_Array'Range;
> 
> This suggests that arrays cannot have more elements than Integer'Last.
> Which cannot be true.

You should have copied the original example: 

Hello_World  : const String := "Hello World!";
subtype Hello_World_Index is Integer range Hello_World'Range;

> What am I missing?

You are missing the definition of String which is part of Standard:

http://en.wikibooks.org/wiki/Ada_Programming/Libraries/Standard

and reads something like this (on GNAT):

 type Integer is range -(2 ** 31) .. +(2 ** 31 - 1);
 subtype Positive is Integer range 1 .. +(2 ** 31 - 1);

 type String is array (Positive range <>) of Character;
 pragma Pack (String);

And indeed the array in the example can not be larger then Integer'Last
because Strings are not larger then Integer'Last.

Of corse you could define:

 type Long_Long_Integer   is range -(2 ** 63) .. +(2 ** 63 - 1);
 subtype Long_Long_Positive is Integer range 1 .. +(2 ** 63 - 1);

 type Long_Long_String is array (Long_Long_Positive range <>) of Character;
 pragma Pack (Long_Long_String);

And then order additional memory for your computer to store
Long_Long_String's in  ;-)

Martin
-- 
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Ada programming at: http://ada.krischik.com