[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: xsl query or transformation language
At 17:28 1998 09 01 +0100, Henry S. Thompson wrote: >Lisa Rein <lisarein@f...> writes: > >> Henry I am a little confused about perceiving XSL as a query language. > >> It was my understanding that it aims to be a transformation language, >> like DSSSL, that works with a query or scripting language to >> transform/process and format data. > >Well, XSL defines its own query syntax for walking the input document >tree, > >a) for the purposes of deciding which style rules to apply to >which input document components (in which case you should think of a >query as returning a 'yes this matches' or a 'no this doesn't match' >result when applied to a node in the tree; Since what gets said here might get copied elsewhere, we should be careful about wording. XSL currently has no style rules and may never. Henry is referring to construction rules here. I would disagree with Henry that pattern matching is querying in any useful, usual sense of the word. If there is a "query" (in the non-technical sense of the word) at all here, it's "given a node in the source document tree, what construction rule's pattern best matches the given node's context?" I don't see this as "returning" anything in the usual sense, and I don't think it's helpful to confuse this with what most people think of as queries even if the syntax of match patterns is similar to (or even the same as) the syntax of select patterns (which is what Henry discusses below). I also disagree that XSL "walks the tree" as Henry mentions above. I agree that the syntax of XSL patterns (both match patterns and select patterns, since they use almost the same syntax) is a potentially useful syntax for an XML-aware query language. > >b) for the purposes of finding one or more bits of the tree to process >next, given a starting point (the node we're processing now), in which >case you should think of a query as returning a set of nodes in the >tree given a starting point. > >A variant of type (b) where you just want the first element of the set >occurs as well. > >Sounds like what I mean by a query language, how about you? 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/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe 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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