enum

[Andrei Alexandrescu]

On 4/9/14, 5:18 AM, w0rp wrote:
> On Wednesday, 9 April 2014 at 11:39:37 UTC, Jonathan M Davis wrote:
>> On Tuesday, April 08, 2014 12:08:46 Andrei Alexandrescu wrote:
>>> 1. Is the current design damaging enough (= allows enough wrong/buggy
>>> code to pass through) to warrant a breaking tightening?
>>
>> What I would very much like to see happen is that any time that any
>> operation
>> is done on a variable of an enum type and that operation is not
>> _guaranteed_
>> to result in a valid enum value, the result should be the enum's base
>> type and
>> and not the enum type - e.g. or-ing enum flags together isn't going to
>> result
>> in a valid enum and shouldn't be typed as such, but unfortunately, it
>> currently _is_ typed as such.
>>
>> And I expect that the vast majority of cases where such a change would
>> break
>> code would catch bugs.
>>
>> - Jonathan M Davis
>
> I think this is a good idea. That way I think you'd only be able to get
> undefined enum values by casting.

Too restrictive. What is a valid enum value? Would an enum flags need to 
ascribe a name to every possible combination?

One possibility would be to guarantee all operations are between 
TheEnum.min and TheEnum.max. Users who need operations would need to 
define those limits.


Andrei