Re: unsigned type

[Jean-Pierre Rosen <rosen@adalog.fr>]

anon a �crit :
>         As for confusing when the index type is defined as Positive, but the 
> compiler and runtime system allows zero.  That's either a compiler Bug or a 
> total lack of reading the RM definition of the terms Natural and Positive types 
> for Adacore and the GNU GCC Ada maintainers.
> 

The idea is that you don't check that bounds belong to the index subtype
if the range is null (i.e., all null ranges are allowed). This is
intended to avoid raising constraint_error if you declare a String(1..0)
Note that it makes code generation for aggregates much more complicated
in some cases - and I wrote the code generator for array aggregates in
Ada-Ed v2, long ago.

So it is not a bug, it doesn't prove that the index is natural, it's
just the intended behaviour, designed in a way that makes user's life
easier - at the cost of compiler writers' life.
-- 
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           J-P. Rosen (rosen@adalog.fr)
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