Checking function parameters in Phobos

[Walter Bright]

On 11/20/2013 3:16 AM, Jonathan M Davis wrote:
> ValidatedString would then avoid any extra validation when iterating over the
> characters, though I don't know how much of an efficiency gain that would
> actually be given that much of the validation occurs naturally when decoding
> or using stride. It would have the downside that any function which
> specializes on strings would likely have to then specialize on ValidatedString
> as well. So, while I agree with the idea in concept, I'd propose that we
> benchmark the difference in decoding and striding without the checks and see if
> there actually is much difference. Because if there isn't, then I don't think
> that it's worth going to the trouble of adding something like ValidatedString.

Utf validation isn't the only form of validation for strings. You could, for 
example, validate that the string doesn't contain SQL injection code, or 
contains a correctly formatted date, or has a name that is guaranteed to be in 
your employee database, or is a valid phone number, or is a correct email 
address, etc.

Again, validation is not defined by D, it is defined by the constraints YOUR 
PROGRAM puts on it.