Re: anchor awareness (was Re: Richer & richer semantics?)

Eliot responding to Tim:
| >Probe 3:
| >
| >1. Current web links are untyped, un-roled (in fact carry no metadata),
| >   and are either single-ended or are a completely opaque query, whereas
 [ ... ]
| Certainly the link elements in HTML have very general types and no explicit
| anchor roles.  Obviously this meets the requirements of a large number of
| Web users, but we also know it doesn't meet the requirements of a
| significant number of others.  I think it's useful to make a distinction
| between "casual linkers" and "thoughful linkers".  Sometimes it's enough
| just to make the connection, othertimes you really need strongly-typed
| links.  The problem with the Web today is it supports the former well and
| the latter almost not at all.  XML will help support the latter, but we
| shouldn't ignore the casual linkers either.

Let's distinguish between what the HTML markup allows and what is
commonly implemented.  From "-//IETF//DTD HTML 2.0//EN", and
dealing only with the A element:

<!ENTITY % linkType "NAMES">
<!ENTITY % linkExtraAttributes
        "REL %linkType #IMPLIED
        REV %linkType #IMPLIED

<!ENTITY % A.content   "(%heading|%text)*">

<!ELEMENT A     - - %A.content -(A)>
        %SDAPREF; "<Anchor: #AttList>"
<!-- <A>                Anchor; source/destination of link      -->
<!-- <A NAME="...">     Name of this anchor                     -->
<!-- <A HREF="...">     Address of link destination             -->
<!-- <A URN="...">      Permanent address of destination        -->
<!-- <A REL=...>        Relationship to destination             -->
<!-- <A REV=...>        Relationship of destination to this     -->
<!-- <A TITLE="...">    Title of destination (advisory)         -->
<!-- <A METHODS="...">  Operations on destination (advisory)    -->

I hold no brief for any of these beyond NAME and HREF, and
in fact I think URN may be an error.  However, any XML hyperlinking 
scheme will have smoother sailing if its proponents can explain 
(not here, but eventually, to the skeptical public) how it relates 
to these semantics.  Even if they're mostly unimplemented, each of 
these attributes on A must be loved by somebody. 

    Terry Allen    Fujitsu Software Corp.    tallen@fsc.fujitsu.com
"In going on with these experiments, how many pretty systems do we build,
 which we soon find outselves obliged to destroy?" - Benjamin Franklin
  A Davenport Group Sponsor:  http://www.ora.com/davenport/index.html