Re: More XSL Discussion

At 07:45 1998 02 25 -0500, Sean Mc Grath wrote:
>[Paul Prescod]
>>
>>>I strongly suspect that XSL will require this balancing *anyhow*. XSL
>>>flow objects are not HTML *code*, they are HTML *elements*. I do not
>>>think it makes sense to create half an element...
>
>A big part of doing it the XSL/DSSSL way (no half elements) is to give the
>render a dig out in knowing when a flow-object is finished to that it can
>do on-the-fly, progressive rendering. This is going to be a hugely important
>aspect of XSL enabled browsers.
>
>OTOH, emitting half an element is both convenient and natural when
>targeting an output format that does not need to be interpreted whilst
>partially complete.

I think there are some theoretical disconnects here.  

Insofar as XSL specifies the mapping of an XML document into a flow object tree,
it clearly makes no sense to talk about "half elements."  The "right hand side"
of an XSL construction rule specifies an action to perform on the flow object
tree that is being constructed.  This tree consists of objects.  There is
no such thing as half an object.  This is where XSL starts from.

Insofar as XSL might be also be designed to allow for the specification of a
transformation from an XML document into another document (XML, HTML, or
whatever--all this remains undecided at this time), I would still claim that
a construction rule is specifying an action to perform on the *tree of objects*
(not a string of characters and markup) that is being constructed even though
that tree may be the "object-modelized form" of what would get serialized
(instantiated) into a document of markup and character data.  

We never talk about creating tags and markup in XSL, we talk about specifying  
the creation of objects/elements, the attachment of characteristics/attributes,
and the copying, creating, suppressing of character data.  XSL is not meant to
specify a character-based transformation process; it does not create an "output
format," it builds a tree; it is inherently object-based.  It makes no sense in 
this light to talk of half elements.

paul


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