Re: Char type verification

[Yves Bailly <kafka.fr@laposte.net>]

Simon Wright wrote:
> I would have thought it would be a lot clearer if you required "<" say
> instead of Hash. To me a hash is typically a pseudo-random conversion
> of a private value to an integral type; if you want ordering, use
> functions with ordering-related names!
> 
> Then you could say
> 
>    return not (upper < value) and then not (value < lower);
> 
> (I think! that's the third time I've rewritten that ...)

Well, I started by writing something like this (without the "and then",
just with "and"). However, the Hash function is required to return a
scalar, so I thought ordering was implied... but you're probably right.
 
> By the way, did you know you can have (library-level, even) generic
> subprograms?
> generic
>    type T is private;
>    type H is range <>;
>    with function Hash(val: in T) return H;
> function Is_In_Range(lower: in T;
>                      upper: in T;
>                      value: in T)
>    return Boolean;

Yes, I know this, I just wanted to provide an example of both a package
and of genericity. Again, you're right, it's just an alternative solution
to me. Maybe there are plenty others :-)

Regards,

-- 
(o< | Yves Bailly  : http://kafka-fr.net   | -o)
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