Re: How can I create an empty array of a generic type?

[reinert <reinkor@gmail.com>]

lørdag 13. juli 2019 23.19.28 UTC+2 skrev Keith Thompson følgende:
> "J-P. Rosen" <rosen@adalog.fr> writes:
> > Le 13/07/2019 à 06:11, Keith Thompson a écrit:
> >> generic
> >>   type Element_Type is private;
> >>   type Key_Component_Type is private;
> >>   with function "<" (Left, Right : Key_Component_Type) return Boolean is <>;
> >>   with function "=" (Left, Right : Element_Type) return Boolean is <>;
> >> package Ternary_Trees is
> >>   type Key_Type is array(Positive range <>) of Key_Component_Type;
> >> private
> >>   Dummy: Key_Component_Type;
> >>   Empty_Key  : constant Key_Type(1..0) := (others => Dummy);
> >> end Ternary_Trees;
> >> 
> >> The Dummy value is a bit ugly. 
> > You can avoid it:
> >    Empty_Key  : constant Key_Type(1..0) := (others => <>);
> 
> Yes, that's better than my suggestion.  (That feature was introduced in
> Ada 2005.)
> 
> -- 
> Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
> Will write code for food.
> void Void(void) { Void(); } /* The recursive call of the void */

But Key_Type is an array indexed by Positive (> 0).  
The zero in "Key_Type(1..0)" is not so intuitive for me (outside the range) ?

reinert