Ceci n'est pas une char

[Walter Bright]

Thomas Kuehne wrote:
> Challenge:
> Provide a D implementation that firsts converts to UTF-32 and has
> shorter runtime than the code below:

I don't know about that, but the code below isn't optimal <g>. Replace 
the sar's with a lookup of the 'stride' of the UTF-8 character (see 
std.utf.UTF8stride[]). An implementation is std.utf.toUTFindex().