[Question] Re: XLink: behavior must go!

John E. Simpson simpson at polaris.net
Mon May 17 04:37:34 BST 1999

At 09:39 PM 05/16/1999 -0400, Simon St.Laurent wrote:
>At 06:05 PM 5/16/99 -0500, Paul Prescod wrote:
>>If a processor it sees <MYLINK ... BEHAVIOR="popup()"> how does the
>>processor know which of the many programming language "plugins" it should
>>be passed to?
>I figured BEHAVIOR would be an ordinary attribute - say, "popup" instead of
>"popup()", which the style sheet or other app-specific gizmo then converts
>to "popup()" as appropriate, knowing what the context was supposed to be.

Aye. That's about what I was thinking, too. The XLink WD, such as it is,
treats the behavior attribute rather gingerly. In 4.1.3 it says:

	A link author can also optionally use an attribute
	called behavior to communicate detailed instructions 
	for traversal behavior. The contents, format, and meaning
	of this attribute are unconstrained.

Later, in the intro to section 6 (Link Behavior), it says:

	In many cases, much finer control over the details of 
	traversal behavior, of the type that existing hypertext 
	software typically provides, will be desired. Such fine 
	control of link behavior is outside the scope of this 
	specification. However, the behavior attribute is provided 
	as a standard place for authors to provide, and in which 
	application software may look for, detailed behavioral 

And that's all it says about the behavior attribute. What seems to
distinguish this from something like "behavior='popup'" -- with or without
the parens -- is that the latter could be presumed to be fairly commonly
desirable link behavior. I'm thinking that where a behavior attribute might
really be useful would be something like:


whose meaning would be understood only by a special-purpose application
that knows how the specified behavior inflects the meaning of the link. Any
general-purpose application would simply treat the link in the "normal" way
(whatever that turns out to be). And this kind of behavior -- like a
page-break PI, and unlike (I think) the behavior specified in the
show/actuate attributes -- wouldn't necessarily be best relegated to a
style sheet or other external entity. It seems inherently "meaningful," and
unable to be captured by any of the other XLinking attributes exactly
because it is application-specific... not in an extension-to-XLink sense,
but it its own right.

But as usual, of course, this is like trying to read really grody entrails.
John E. Simpson            | The secret of eternal youth
simpson at polaris.net        | is arrested development.
http://www.flixml.org      |  -- Alice Roosevelt Longworth

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