private static bool IsAlpha (char c)
{
#if NET_2_0
// as defined in rfc2234
// %x41-5A / %x61-7A (A-Z / a-z)
int i = (int) c;
return (((i >= 0x41) && (i <= 0x5A)) || ((i >= 0x61) && (i <= 0x7A)));
#else
// Fx 1.x got this too large
return Char.IsLetter (c);
#endif
}