Re: How to best make a custom range?

["Randy Brukardt" <randy@rrsoftware.com>]

"AdaMagica" <christ-usch.grein@t-online.de> wrote in message 
news:bbdac1c2-53e9-4b26-a9da-580c988b6b1d@googlegroups.com...
> Am Dienstag, 5. November 2019 16:10:46 UTC+1 schrieb Shark8:
>>    TYPE Digits is range 0..9;
>>    SUBTYPE Odds is Digits with Static_Predicate => Odds in 1|3|5|7|9;
>> what should Odds'Pred(1) be? 0? Constraint_Error?
>> what about Odds'Pos(1) should it be 0, the first item of the subtype? Or 
>> 1, the position in the parent-type?
>
> Attributes work on the base type, e.g.
>
> Natural'Pred (0) = -1

Right, but it's a case-by-case thing as to whether an attribute applies to 
the type or to the subtype. The ones you're talking about apply to the type 
(not any subtype), but 'First and 'Last apply to the subtype.

                                             Randy.