Re: RFC7208 upper case macro expansion ambiguity

On Saturday, August 02, 2014 14:19:17 Stuart D. Gathman via spf-discuss wrote:
> RFC7208 describes upper case macro expansion as follows:
> 
>    Uppercase macros expand exactly as their lowercase equivalents, and
>    are then URL escaped.  URL escaping MUST be performed for characters
>    not in the "unreserved" set, which is defined in [RFC3986].
> 
> RFC3986 tells us that:
> 
>    unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"
> 
> The question is, may an implementation URL escape chars that *are* in
> the unreserved set?  For instance, if localpart is "~ralf",
> is an %{L} expansion of "%7Eralf" acceptable?  Or should the
> test suite mandate an expansion of "~ralf"?  What about silly
> choices like expanding ALPHA chars?

I think no.  As you point out, if you can expand "~" you can expand anything 
and then you get silly results.  

Scott K