Replace core language HexStrings with library entity

[David Nadlinger via Digitalmars-d]

On Monday, 16 March 2015 at 18:58:11 UTC, Andrei Alexandrescu 
wrote:
>> I suggest to implement only ubyte[] first. And wait for 
>> enhancement
>> requests.
>
> At a minimum we need the built-in replacement. -- Andrei

cast(string)hex!"…" works just fine as a built-in replacement 
(where hex returns an ubyte array).

Why should we repeat the same design mistake if we are going to 
break people's code anyway?

  — David