- From: Jon Bosak <bosak@atlantic-83.Eng.Sun.COM>
- Date: Tue, 21 Jan 1997 11:48:25 -0800
- To: w3c-sgml-wg@www10.w3.org
- CC: bosak@atlantic-83.Eng.Sun.COM
[David Durand:]
| If the ERB propagates it working decisions in the form of a
| complete preliminary proposal before we have a directed
| design-decision by design-decision discussion, I predict that the
| final result will be strongly determined by the initial proposal. This
| may be good or bad, but it is likely to happen.
Let's review.
On December 19, Tim Bray proposed a process for defining the goals and
principles for Phase II of this activity. He started it off with a
straw proposal for a list of design goals entitled Minimum Progress
Required to Declare Victory. I reproduce that message at the end of
this post for those who may have forgotten it. He attempted to define
a process for refining his proposal as follows:
| Sensible reactions to this proposal include:
| - suggestions that we add facility X, because it's easy and useful
| - suggestions that we add facility X whether it's easy or not because
| it's such a basic need that we're wasting our time if we leave it out
| - suggestions that we remove facility X, because it'll get us in trouble
| - suggestions for compliance, at some level, with some existing standard
| - meta-suggestions for good ways to structure this discussion
| - comprehensive yet compact fully thought out proposals for a hyperlinking
| facility, supported by multiple public-domain reference implementations
Soon after he had made this proposal, Tim attempted to get
participants to respond to specific points in a way that would create
an organized list of design principles:
| Martin, your contribution addresses two points in the MPRDV note,
| which could either be identified by number (3.2sub2, 3.3) or name
| (addressing un-ID'd objects, link-end to address sets.) To achieve
| some sort of order in this discussion, it would help if people would
| use the "Subject:" line to support discussion threads at a level
| somewhat narrower than "Hyperlinks".
This attempt to set up a discussion of goals in advance of specific
proposals has largely been ignored by everyone, including those who
are now complaining about a lack of process. After letting the
conversation free-wheel for a while (a completely conscious decision
for which I take full responsibility), Tim, concluding (I believe)
that his original proposal would stand as our guide, moved the
discussion forward by suggesting a concrete proposal in a message of
December 29:
| All this discussion has been quite educational, but the proportion of
| it that I can relate to the problems that I as co-editor will soon be
| facing is kind of low.
|
| I think it's time for a strawman. [...]
Eliot responded to this a few days later with a very useful
HyTime-based "house of sticks", and that's why we are now talking in
terms of proposals.
The ERB feels that we are now ready to look at an actual straw
proposal, and the co-editors of the link draft are preparing one even
as we speak. You should have their initial attempt before you within
the next day or so.
I'm sorry if anyone feels that there hasn't been enough time spent on
a discussion of goals before considering specific proposals, but it
certainly wasn't for a lack of opportunity. Looking back over the
last month of discussion, I personally am of the opinion that we
couldn't have made better progress without chewing on various aspects
of the problem in the way that we have done, and I think that we are
as ready as we will ever be to move forward within the organization of
a specific plan. I don't know exactly what the draft co-editors will
be presenting, but I am confident that it will take into account all
the many insightful contributions made to this list (I would like to
recognize Dave's work in particular, without which we could not have
come as far as we have in understanding the issues) and that it will be
the best starting point that we could hope for at this stage.
Jon
########################################################################
Date: Thu, 19 Dec 1996 20:19:45 -0800
To: w3c-sgml-wg@www10.w3.org
From: Tim Bray <tbray@textuality.com>
Subject: Hyperlinks: MPRDV
In the meeting of Dec. 18, the ERB discussed how we might start moving
forward on hyperlinking. Attempts to proceed as we did with the base
XML language, i.e. agree on a statement of principles and start
subsetting an existing standard, seem fraught with difficulty; in
particular it seems very difficult to separate the meta-discussion of
design goals from the discussion of implementation details and
standards compliance.
To help get things going, and after running this idea past the ERB, I
am introducing a proposal entitled Minimum Progress Required to
Declare Victory. The idea is to continue running with the XML
premise; that you can do a lot with a little. In particular, we
should be able to offer the Web community something subtantially
better than they're used to without having to go very far. It should
be borne in mind that to do a good job on specifying even a little,
you have to fight through some surprisingly hairy problems (as witness
our recent experience on this list). This is an attempt to spot the
low-hanging fruit in the hyperlinking jungle.
Sensible reactions to this proposal include:
- suggestions that we add facility X, because it's easy and useful
- suggestions that we add facility X whether it's easy or not because
it's such a basic need that we're wasting our time if we leave it out
- suggestions that we remove facility X, because it'll get us in trouble
- suggestions for compliance, at some level, with some existing standard
- meta-suggestions for good ways to structure this discussion
- comprehensive yet compact fully thought out proposals for a hyperlinking
facility, supported by multiple public-domain reference implementations
This will presumably launch us on a fairly free-form discussion
ranging from philosophy through implementation, which is no bad thing
at this stage. At some point we will have to impose structure on the
discussion and generate a draft and so on; this point will doubtless
arrive before many of us are comfortable that we're ready. Speaking
unofficially, but I think on behalf of the ERB, it seems that the
breakneck pace at which we plowed through XML was on balance a good
thing, and we'll try to stick with that.
Having said all this, I should emphasize that while the ERB gave me
the OK to post this and get things going, it is *not* a position of
the ERB, and no hint should be taken that we are leaning in this
direction or any other. Once again, it will be helpful if those
responding use subject lines to help sort out threads.
I'll place an HTML version of this at
http://www.textuality.com/sgml-erb/mprdv.html
=================================================================
Minimum Progress Required to Declare Victory
1. Background
The Web is the largest working hypermedia instance. It supports one
widely-used form of hyperlink, the <A> or Anchor element. These links
are unidirectional and [this is a basic design principle of the web]
specify basically nothing about their target except its location. The
links carry no typing or role information, beyond the unconstrained
text that may be found between the <A> and </A> tags. HTML offers
another hyperlink facility, the LINK header element, but it is not
widely used.
Web links support a variety of behaviors, governed by the interaction
of the "scheme" part of the URL (http:, file:, ftp:, mailto:) and the
logic in the "User Agent" (typically a browser). It might be argued
that there are really a smaller number of behaviors (a) retrieve and
display, (b) retrieve and save, (c) send mail; but the number of
behaviors exceeds one.
There are a variety of other standards that support hyperlinks, of
which the most visible are HyTime, part of TEI, and in the area of
object naming, the IETF URN work. None of these, at this moment, has
overwhelming market acceptance, or credibility at the level enjoyed by
SGML. HyTime has ISO's blessing, URN has the IETF's; TEI is used to
encode many billions of bytes of text.
2. Minimum Progress on Deliverables
The minimal deliverable is a smallish document (smaller than the XML
spec) with an independent existence and name - for example, XHA for
Extensible Hyperlink Architecture. The hyperlinking mechanisms should
be applicable to XML of course, but also to SGML and (to the extent
possible) to HTML.
XHA should have no dependency on XML. However, we may choose to build
special machinery into XML (reserved elements/attributes/archforms) to
optimize support for XHA.
3. Minimum Progress on Hyperlink Enhancement
The minimum set of hyperlink constructs should:
3.1 subsume the existing WWW Anchor semantics in a smooth and natural way.
3.2 provide a hyperlink mechanism with richness similar to that of the
HyTime "ilink" construct. This means that the link
- has a type,
- has multiple ends, each of which has a role, and
- may be located away from any of its ends, thus supporting links into
read-only material.
3.3 support addressing at least by URL and ID attribute, alone or
in combination.
4. Minimum Progress on Behavior
The minimum set of behavior machinery should provide:
4.1 mechanisms for users to identify and describe behaviors associated with
hyperlinks.
4.2 predefined behaviors equivalent to those already in wide use on the Net.
5. Minimum Progress on Link Roles
The minimum set of link role machinery should provide:
5.1 mechanisms for users to identify and describe roles for link-ends.
5.2 predefined link roles equivalent to those already in wide
use on the Internet
Cheers, Tim Bray
tbray@textuality.com http://www.textuality.com/ +1-604-488-1167
Received on Tuesday, 21 January 1997 14:49:19 UTC