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RE: "Outline" algorithm (document length and complexity)

From: Larry Masinter <masinter@adobe.com>
Date: Sat, 20 Jun 2009 16:18:26 -0700
To: HTML WG <public-html@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118CDAC7162@nambx04.corp.adobe.com>
(I ran out of time before vacation to reply to previous threads,
and have a lot of backlog, alas)

I don't think there has been a satisfactory reply to the
question about section "Creating an outline".

Text is either normative (something that HTML agents must
implement) or informative (explanatory information that
helps understand the rest of the spec) or else an 
auxiliary specification of some optional processing.

There appears to be only one reference anywhere in 
the rest of the document to Section or to the
word "outline" -- unless I've missed something somewhere?

The reference in section 4.8.1 which only requires knowing
whether an image is associated with an heading, which 
surely can be described more simply.

If there are no (other) normative requirements, how can 
conformance be judged? 

If the text is intended to be informative, how does
this text understand the spec?

If this is optional processing that might be "useful"
for " tools to aid authors" such as the
imagined "editors" that "expose the outline explicitly",
where are the requirements, use cases and so forth for
such editors? Shouldn't editors also "clean up" the
HTML so that a simpler outline generation algorithm
could be used? Is it necessary to specify conformance
for all HTML, or would it be sufficient to specify
how outlines are to be computed only for well-structured
HTML that has been 'tidied'?

Finally, if this is mainly an authoring tool
conformance requirement, and authoring conformance
requirements are removed to a separate document,
shouldn't the authoring tool conformance requirements
also be moved?


-----Original Message-----
From: Ian Hickson [mailto:ian@hixie.ch] 
Sent: Tuesday, May 26, 2009 1:24 PM
To: Maciej Stachowiak
Cc: Larry Masinter; HTML WG
Subject: Re: "Outline" algorithm (document length and complexity)

On Tue, 26 May 2009, Maciej Stachowiak wrote:
> On May 26, 2009, at 11:24 AM, Larry Masinter wrote:
> >
> > Yes, that would be a bad editorial decision. The question is why 
> > "outline" is part of the vocabulary. What features of HTML use the 
> > "outline" function?
> [...] I think a typical UA would not make use of these semantics 
> directly.

A typical browser wouldn't, but many tools would. For example, th HTML5 
spc itself has a table of contents which is generated using an 
implementation of this very algorithm.

> To turn the outline algorithm into something that can produce testable 
> assertions, it would have to be exposed in some way, either as a DOM 
> interface or by affecting the rendering. If that were done, we could 
> better evaluate it. But I would question the value of a DOM API to 
> expose the outline.

I don't think Web browsers should implement this; this would be something 
that would be implemented (indeed, has already been implemented) in tools 
to aid authors. One could imagine editors exposing the outline explicitly, 
like word processors do.

> From all this I conclude that the current outline section is not a 
> useful piece of spec. It does not currently imply any testable 
> assertions for implementations, and if it did, it would be exceedingly 
> difficult to write and validate a practical implementation.

This seems a very browser-specific outlook. :-)

Incidentally, I do think that section would benefit from being phrased in 
a clearer way. I've already tried to improve it once, with only limited 
success. If anyone can think of a way to better describe this part of the 
spec I would be very happy to update it accordingly.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Saturday, 20 June 2009 23:25:04 UTC

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