CTFE implementation

[Frank Benoit]

I want to initialize constant GUID structure instanzes in D1. This is 
part of doing a port, so i want to keep most of the original code unchanged.

In Java:
public static const GUID IIDJavaBeansBridge = 
IIDFromString("{8AD9C840-044E-11D1-B3E9-00805F499D93}");

This is in Java no problem, IIDFromString is executed at startup.
In D i could change it too this:
public static const GUID IIDJavaBeansBridge = { 0x8AD9C840, 0x044E, 
0x11D1, [0xB3, 0xE9, 0x00, 0x80, 0x5F, 0x49, 0x9D, 0x93]};

This compiles, but there are many of these GUID constants and for later 
merges and diffs, i really would like to keep the Java form. So i 
thought CTFE might do the trick.

// struct GUID { // size is 16
// align(1):
//     DWORD   Data1;
//     WORD    Data2;
//     WORD    Data3;
//     BYTE[8] Data4;
// }

int HexToInt( char[] str ){
     uint i = 0;
     foreach( c; str ){
         i <<= 4;
         int v = -1;
         if( c >= 'A' && c <= 'F' ){
             v = c - 'A' + 10;
         }
         else if( c >= '0' && c <= '9' ){
             v = c - '0';
         }
         assert( v >= 0 && v < 16, "for "~str~" char "~c );
         i |= v;
     }
     return i;
}

private static GUID IIDFromString( char[] str ){
     assert( str.length is 38 );
     assert( str[0] is '{' );
     assert( str[9] is '-' );
     assert( str[14] is '-' );
     assert( str[19] is '-' );
     assert( str[24] is '-' );
     assert( str[37] is '}' );
     GUID res;
     res.Data1 = HexToInt( str[1 .. 9] );
     res.Data2 = HexToInt( str[10 .. 14] );
     res.Data3 = HexToInt( str[15 .. 19] );
     //res.Data4[0] = HexToInt( str[20 .. 22] );
     //res.Data4[1] = HexToInt( str[22 .. 24] );
     //for( int i = 0; i < 5; i++ ){
     //    res.Data4[i+2] = HexToInt( str[25+2*i .. 25+2*i] );
     //}
     return res;
}

This works for the member Data1, Data2, Data3. But not for the Data4 
member, which is a static array. Uncommenting those lines yield the 
"cannot evaluate at compile time" error.

I tried to do a union, also without luck.

Does someone have a solution for this?