Why can't D store all UTF-8 code units in char type? (not really understanding explanation)

[thebluepandabear]

> :-D
>
> (Exercise for the reader: what's the Hausdorff dimension of the 
> set of strings over Unicode space? :-P)
>
>
> T

Your explanation was great and cleared things up... not sure 
about the linear algebra one though ;)