Voldemort toHexString Compile Error

[Salih Dincer]

On Sunday, 17 March 2024 at 13:08:14 UTC, Richard (Rikki) Andrew 
Cattermole wrote:
> It is because Hex is nested, it has an outer pointer to the 
> call frame of toHexString.
>
> Make Hex static, and it works.

Thank you for your contributions. It's great to develop something 
with you. So is having such a forum. Thanks everyone, here is the 
new version:

```d
auto toHexRange(T)(const char[] str)
{
   static struct HexRange {
     int i;
     auto nibbleSplit() {
       auto MSB = i >> 4;
       auto LSB = i & 15;
       return [MSB, LSB];
     }
   }
   import std.utf : byCodeUnit;
   import std.algorithm : map;
   import std.range : join;

   return str.byCodeUnit.map!HexRange
             .map!(e => e.nibbleSplit).join
             .map!(n => n += n > 9 ? '7' : '0')
             .map!(c => c.to!T);
}

auto toHex(T)(const char[] str)
{
   static if(is(T : string))
   {

     import std.algorithm : copy;

     auto result = new char[str.length * 2];
     str.toHexRange!char.copy(result);

     return cast(string)result;

   } else {

     import std.array;

     return str.toHexRange!T.array;
   }
}

unittest
{
   enum Expected = "61626320C3A4C3B6C3BC50C39FE282AC207B447D";
   enum str = "abc äöüP߀ {D}";

   assert(str.toHex!string == Expected);

   import std.conv : hexString;
   static assert(hexString!Expected == str);

   enum NATO {
     Alpha = '0', Bravo, Charlie, Delta, Echo,
     Foxtrot, Golf, Hotel, India, Juliett,
     Kilo = 'A', Lima, Mike, November, Oscar, Papa
   }

   auto test = str.toHex!NATO;
   assert(is(typeof(test) : NATO[]));
}
```

SDB at 79