Re: REL and REV attributes (Was: More comments on HTML 3.0)

Bert Bos (bert@let.rug.nl)
Mon, 1 May 95 11:36:13 EDT

Amazing how fast things can change on this list! Exactly a week ago,
in the midst of a much longer document ("More comments on HTML 3.0"),
I repeated something I had said earlier, namely that I didn't see what
REV could add that REL couldn't express.

That short line got picked up, but nobody seemd to agree with me. But
suddenly everything has changed, REL is going to be standardized in an
HTML-independent way, and REV is going to be dropped. Nice work!

If I interpret the last messages by Dan Connolly and Craig Hubley
correctly, then it seems that REL is the functor of a 2-place
predicate, the 1st arg of which is the current document, the 2nd is
the document in the HREF-attribute, or symbolically: "REL(BASE,HREF)"

Furthermore, the value of REL will be something like:

scheme:/valuepart/valuepart/.../valuepart

(much like URLs, including the rules for relative values). For
example:

htmllink:/parent
htmllink:/next
htmllink:/x-uncle
previous *)
ToC *)
cooklink:/recipe/expensive
cooklink:/recipe/cheap/vegetarian
mathlink:/corrollary
mathlink:/example
x-proprietary:/opaque0/opaque1

*) For the moment, the implicit BASE is "htmllink:/", so that
"previous" expands to "htmllink:/previous".

|Dan writes:
|> This is very much the crux of the matter: are we defining a global
|> formal semantics, or just a global syntactic mechanism upon which
|> folks can build application-specific formal semantics?

Both: a global syntactic mechanism and a semantics for one corner of
that world. (The same is true of URLs).

Bert

-- 
                          Bert Bos                      Alfa-informatica
                 <bert@let.rug.nl>           Rijksuniversiteit Groningen
    <http://www.let.rug.nl/~bert/>     Postbus 716, NL-9700 AS GRONINGEN