Re: [dgd@cs.bu.edu: BOS confusion (analysis; suggestion to resolve Newcomb/Bryan conflict)]

>I don't know what Martin means by "link chains". This is not a HyTime term.
>If he means "location ladders", then you can have location ladders without
>requiring entity declarations (although the use of entities would be the
>SGML/HyTime recommended method).

I did mean location ladders. The HyTime TC says (twice, so you have to
believe it!) that "The ultimate location source for any location ladder is
the root of a grove". It also says "If the location source is a document,
subdocument or data entity, the location source is within the grove
constructed from that entity". (Note the use of the term entity!)

In XML terms, where application dependent groves are not likely to be
permitted, this in practice means the root of the file being referenced if
no finer resolution is given in the pointer as it has to be presumed that
the reference is to a free-standing XML document. While this reference could
be done indirectly using a query that contains a URL the SGML way of
identifying files is by having the root of the document identified via a
uniquely named entity declaration. 

What I am unclear about is what would constitute a the grove of something
pointed to using a URL of the form report.html#point1 if the HTML page
pointed to was constructed as follows:

<p>The points raised were:
<ul><li><a name=point1></a>How useful is HyTime
<li><a name="point2"></a>How useful is HyTime

Given the fact that most documents on the Web would not allow sensible
groves to be constructed from existing named anchors the relevance of HyTime
location sources for linking XML files to HTML anchors must be considered.
My personal preference would be to say that pointers to named HTML anchors
should be handled by a special architectural form that has nothing to do
with HyTime location addresses, but that we provide HyTime compatible
architectural forms for handling links that cannot be expressed using the
far-too-simple HTML anchor constructs.

Martin Bryan, The SGML Centre, Churchdown, Glos. GL3 2PU, UK 
Phone/Fax: +44 1452 714029   WWW home page: http://www.u-net.com/~sgml/