Re: [Newbie] doubly constrained array, dumb question

["J-P. Rosen" <rosen@adalog.fr>]

Le 26/02/2018 à 17:26, Mehdi Saada a écrit :
> Hello.
> 
> I would like an constrained String subtype with narrower bounds that Positive'Range.
> How can I do something like:
> subtype Possible_Length is NATURAL range 1..80;
> subtype T_Line is String (Possible_Length range <>);
> ? I know "range <>" isn't included in the definition of "range_constraint". How can I express the same thing.
> So that I can get after, a dynamic string with:
> A: access T_LINE := new T_LINE'("BLABLABLA"); while checking for its range.
> 
You can't do that, because a subtype can't be both constrained and
unconstrainde at the same time...

OTOH, you can define your own string type:
type Short_String is array (Possible_length range <>) of character;

Note that this type will still enjoy string literals, and can be
converted back and forth to String.


-- 
J-P. Rosen
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