more OO way to do hex string to bytes conversion

[Ralph Doncaster]

I've been reading std.conv and std.range, trying to figure out a 
high-level way of converting a hex string to bytes.  The only way 
I've been able to do it is through pointer access:

import std.stdio;
import std.string;
import std.conv;

void main()
{
     immutable char* hex = "deadbeef".toStringz;
     for (auto i=0; hex[i]; i += 2)
         writeln(to!byte(hex[i]));
}


While it works, I'm wondering if there is a more object-oriented 
way of doing it in D.