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Re: 2.3: Link Recognition by PI or other signal?




>The ERB schedule calls for voting on these Feb. 19th.
>
>2.3 Should we provide a PI or other signaling mechanism whereby a document
>    can specify that particular elements ought to be processed as link
>    elements?

Yes. Definitely. I would suggest PIs to be used to assign elements and/or
attributes the role of links. This - I think - should simplify issues

2.1 a-d: Link Recognition by Reserved Attribute
2.2 a-b: Link Recognition by Reserved GI
2.4:     Link recognition by processor fiat

as well.

Cheers,

Hasse


P.S.

Not to push a badly veiled agenda, beneath is an excerpt from the
Synex ViewPort documentation to illustrate what we have found to
be a useful design. The PIs are used to register customized
hypertext and elements using the TEI P3 extended pointer syntax.
(Customized hypertext triggers callbacks, whereas the TEI extended
pointers are handled internally).


ViewPort supports two ways of registering link elements:

- by element, or
- by element if a specific attribute is non-implied

The element can be specified either by its generic
identifier (element name) or by an architectural form.

Processing instructions are used for the registration. In
the PI examples below, the "tag-link" registers a hyperlink
element, and "att-link" a hyperlink defined using an element
with a non-implied attribute.

Examples:

<?TAGLINK A "URL">

 All elements named A become customized hypertext
 elements with the hyperform URL.


<?ATTLINK A HREF "URL">

 All elements named A become customized hypertext
 elements with the hyperform URL if the
 corresponding element has an non-implied
 attribute named HREF.


<?TAGLINK #ARCHFORM HTMLFORM ANCHOR "URL">

 All elements having an attribute named HTMLFORM
 assigned the value ANCHOR become customized
 hypertext elements with the hyperform URL.


<?ATTLINK #ARCHFORM HTMLFORM ANCHOR HREF "URL">

 All elements having an attribute named HTMLFORM
 assigned the value ANCHOR become customized
 hypertext elements with the hyperform URL if
 it has an non-implied attribute named HREF.

The syntax of the processing instructions in formal terms is:

tag-link  :- 'TAGLINK' element hyperform [ param ]

att-link  :- 'ATTLINK' element attribute hyperform [ param ]

element   :- NAME |
             '#ARCHFORM' attribute value

attribute :- NAME

value     :- LITERAL

hyperform :- LITERAL

param     :- LITERAL

A hypermedia form (hyperform) is an application-dependent
keyword. ViewPort reserves "TEI-P3" internally, for the TEI
extended pointer functionality. Panorama uses "URI" as
the hyperform for its URL support.

For ViewPort, the processing instructions must be included
in the SGML document prior to the parsing of the document
instance (in the DTD or document type declaration subset).







--
Hasse Haitto                          Phone:    +46 8 791 88 81
Synex Information AB                  Fax:      +46 8 791 88 89
Stora Nygatan 20                      Internet: haitto@synex.se
S-111 27 Stockholm, Sweden            WWW:      http://www.synex.se