Re: percent-encoding in tel URIs

Erik Wilde wrote:

> reuse the phone number definition in the tel URI scheme

| local-number-digits  =
|     *phonedigit-hex (HEXDIG / "*" / "#")*phonedigit-hex
.......................................^

TILT, game over.  I think that was never correct, compare
RFC 2396 section 2.4.3 "excluded US-ASCII Charactes".  

Simplified, after an <authority>, if you use this, you
have to match a path/query/fragment structure, even if 
you don't need any path/query/fragment.  In the "path"
you can use any <pchar> as is.  Notably not "/" (unless
it separates path-segments), not "?" (starts a <query>),
not "#" (starts a <fragment>).  As soon as you are in
the <query> you can also use "/" and "?" as is, but not
"#" (still starts a <fragment>).

Some VCHARs are *never* okay, e.g., "<", ">", "{", "}",
and '"'.  Wherever you are in the URL, they have to be
percent-encoded.  Ditto "[" and "]" unless they delimit
IPv6- or IPvFuture literals in the <authority>.

IIRC "#" is also never allowed as is, unless it starts
a <fragment>.  If you want to use tel: maybe start with
a 3966bis (?)

 Frank