xml-dev - Re: XML-LINK

["W. Eliot Kimber" <eliot@isogen.com>]

At 09:53 AM 6/1/97 GMT, Peter Murray-Rust wrote:

>So I am extremely wary of starting to code anything more in this area until
>its limits become clear.  It's clearly venturing into rocket science
>territory.  By comparison XML-LINK=SIMPLE is relatively straightforward.
>Therefore I suspect there will be implementers (like myself) who find that
>full XML-LINK implementation is too difficult/expensive/undefined, whilst
>SIMPLE is useful and doable.

Remember that there are two basic "modes" of link processing: 

1. The "I know everything mode", in which you need both to know the
boundaries of the documents you need to know about (i.e., a "bounded object
set") and a general processor capable of doing the processing and holding
the result for some reasonable length of time. This is the
HyBrowse/Hyper-G/Intranet approach, in which the bounds of the system are
fairly well defined and you have the infrastructure you need to manage all
the link information more or less persistenty.

2. The "I only know about what I have seen or am now seeing" mode.  This is
the normal "Web" mode or the Panorama mode (except that Panorama only
remembers what it knows about the current document, unfortunately).

If you constrain your links to be in line ("contextual"), whether using the
SIMPLE or EXTENDED syntax, then the second mode can always be applied and
any XML browser should be capable of handling it (if you can handle SIMPLE
you can handle inline EXTENDED links and EXTENDED links in the document
you're processing).  This is not an unreasonable constraint to have as it
greatly simplifies processing (the Web is forced to impose this constraint
for the general case, as the Web is so large it is effectively unbounded).

Note that the two modes can be combined, such that you might know
everything about one set of documents but only about pointers to another
set.  The data structures needed to manage knowledge of the links is the
same in both modes, the only question is when do you gather the knowledge?

Cheers,

E.

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