Checking function parameters in Phobos

[Simen Kjærås]

On 2013-11-21 08:38, Jacob Carlborg wrote:
> On 2013-11-21 01:16, Simen Kjærås wrote:
>
>> The result of re-validating is performance loss. The result of missed
>> validation is a bug. Also, in just a few lines, you can make a version
>> that will *not* decay to the original type:
>>
>>    struct Validated(alias fn, T) {
>>        private T _value;
>>        @property inout
>>        T value() {
>>            return _value;
>>        }
>>    }
>>
>>    // validated() is identical to before.
>>
>> Sure, using it is a bit more verbose than using the unadorned type,
>> which is why I chose to make the original version automatically decay.
>> This is a judgment where sensible people may disagree, even with
>> themselves on a case-by-case basis.
>
> It's still accessible via "value".
>

Indeed it is. If we want to make it perfectly impossible to get at the 
contents, so as to hinder all possible use of the data, I suggest this 
solution:

struct Validated {}

Validated validate() {
     return Validated.init;
}

--
   Simen