[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: [SML] Whether to support Attribute or not?
SML cannot drop attributes unless it provides a resonable alternative. On Sun, 28 Nov 1999, John Cowan wrote: > > <element att="val"> <content/> </element> > > How about this? > > <element <att>val</att>> <content/> </element> > > This is for sure not XML/SGML, but it generalizes the recursive > pattern. If you want an attribute on the attribute, you write: > > <element <att <att-of-att>subvalue</att-of-att>>val</att>> ... Thanks John. Didn't even think of this. It would definately allow for recursive attributes -- and a clear distinction between meta informatoin (attributes) and content information. Very nice. Unfortunately, it breaks with XML compatibility... thus, we are left with this question: Is having a syntax level distinction between information and information about the information (meta information) necessary? I'm uncertain, but leaning towards "yes" for my vote. IMHO, there is a huge difference between the two. Take the following HTML fragment: <table border="2" cellpadding="50"> <tr><td>One</td><td>Two</td></tr> <tr><td colspan="2">Three</td></tr> </element> I clearly see the different role that content plays as opposed to attributes. The border and cellpadding attributes *modify* the state of the table; where the tr element content is *part-of* the table. The border attribute recurisvely applies to every one of the table's children by virtue of how the table is drawn. In a similar way, the colspan changes the last td element so that its funciton is completely different -- a child of td does not have this power. On a side (but very important) note, the attribute syntax allows all of these modifiers to be expressed *before* the first element content. >From a pratical sequential processing perspective, this syntax distinction is very necessary -- otherwise one would have to wait until the entire content of an element to be read "just-in-case" one of the children modified its parent. This would be a nightmare, and would require random access... hence more memory, and thus, completely undermine SML's application to less powerful devices. >From a philosophical perspective, the attributes define the "whole", where the content defines the "parts". Mixing them leaves a nasty taste in my mouth. I assume there is a fundamental reason for this seperation in SGML, and thus in HTML and that it did not arrive by accident. Could the above comments be part of the reason? So.... SML cannot drop attributes *unless* is provides an alternative approach. This approach should support the attributes (those things which apply to the whole) appearing first, and the content occuring afterwords. Ideally, the alternative approach would allow for recursion as well... hence John Cowan's suggestion is brilliant... However, it's not XML compatible. Is this *such* a big deal? How hard would it be to make a parser that could handle both.... Best, Clark xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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