[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XSL intent survey
> I probably don't know enough about > document stylesheets to understand why you need the formatting objects > and perhaps someone on the list can explain. Because you want to specify the format of the output:-) You are probably thinking in terms of HTML where there is some kind of default formatting for a fixed set of elements (based on historical actions of the browsers, mainly) and typically style sheets are used just to tweak or fine tune those defaults. For XML you don't have any default semantics, so if you want to say that the content of a <p> element should be typeset as a paragraph you need some way of referring to the abstract notion of a paragraph. That's what the paragraph formatting object is. Similarly the other formatting objects give the fixed set of `typographic' (may be rendered as speech or braille or whatever) facilities that should be implemented. It is rather sad that the `suggested' answers in this survey didn't suggest the most obvious language on which to base this system (as it is in fact the language on which large parts of XSL are based) namely dsssl. (`base' can be taken rather loosely, for example people seem not to like dsssl syntax (for (some (strange (reason))))). DSSSL had two separate languages. A transformation language and a style language. As far as I know the transformation part never got implemented. The major reason why the non implementation of dsssls transformation language has not turned out to be important was that James Clark showed how one could effect transformations using the style language (by having a set of flow objects that write SGML instances). a dsssl flow object is more or less the same thing as an XSL formatting object but in the current XSL draft this mechanism of using the same paradigm to do both transformations and style is more cleanly expressed than in dsssl (where it is a more or less non standard extension). XSL has other problems (its transformations and patterns are not powerful enough to say do anything with MathML), and it doesn't have many of the needed formatting objects, but that does not worry me too much as it is explicitly says in the draft that more will be added later. Actually I can not see any use at all for having a style language that can not do transformations. Given that you are going to have to transform the original parse tree to produce the required output tree for the formatting, why not just add the formatting characteristics as you construct that tree (as you can do in a combined language) rather than have to go over the tree again adding formatting characteristics with a second style language? David XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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