string need to be robust

[Andrei Alexandrescu]

On 3/13/11 1:55 PM, Jacob Carlborg wrote:
> I would say that the functions should NOT crash but instead throw an
> exception. Then the developer can choose what to do when there's an
> invalid unicode character.

Yah. In addition, the exception should provide index information such 
that an application can elect to continue processing.

Andrei