Re: Do I need to use a validating parser?
* Joshua E. Smith | | Nonetheless, always up for the academic discussion, you can express | the entire syntax of the LISP programming language in less than a | page of DTD, I bet. You can, but then you lose some of the really interesting things, such as read-macros and dispatching characters. It's hard to see any valid equivalents of those. For good examples of read-macros, see <URL: ftp://ftp.netcom.com/pub/hb/hbaker/Prag-Parse.html> * Steve Oldmeadow | | I don't know LISP but how would you express scoping rules such as a | locally defined variable can only be accessed within the block it is | defined such as in Java? Like type-checking this is generally considered to be semantics and so one wouldn't normally expect a grammar to be able to express this. (In fact, I don't think it's possible using a context-free grammar.) | I came to the conclusion that XML added very little and that you | were better off just using the traditional tools to generate a | parser for your language. I certainly have to agree here. I think I prefer the approach taken by someone else recently: parse the language syntax into XML and then apply stylesheets and parsers to the XML for documentation, pretty-printing and whatever. | One thing I toyed with was whether a yacc like tool would be useful | for XML-ish languages, in other words it would help you generate | parsers for languages that are marked up using XML. This is probably possible, and I think this is what some of the alphaWorks tools do. Also, I already have an unreleased Python package which can turn some kinds of XML documents into sets of elements using some simple rules. This completely does away with the entire application-specific parser notion and just lets you use the objects. It doesn't work for all kinds of documents, though, but I think it might be possible to extend it to do so. --Lars M. 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 (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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