Re: Ada case-statement

[Stephen Davies <joviangm@gmail.com>]

On Wednesday, 14 March 2018 23:16:29 UTC, Randy Brukardt  wrote:

> declare
>   Selector : Day_Type renames Calculate_Day;
>   subtype Weekend_Subtype is Day_Type range Sat .. Sun;
>      -- Or use a static predicate if the range is discontiguous.
> begin
>   case Selector is
>       when Mon .. Fri =>
>          ...
>       when  Sat | Sun =>
>          ...
>          case Weekend_Subtype'(Selector) is -- A type conversion works, too.
>             when Sat =>
>                ...
>             when Sun =>
>                ...
>          end case;
>    end case;
> end;

Unless this has changed in more recent compilers, the static predicate
when Sat & Sun are not contiguous does not work. Gnatpro 7.0.2 complains
about missing values. Also, attempting to use "when Weekend_Subtype" in
the outer case-statement results in complaints about duplicate values.