Re: If XML is too hard for a programmer, perhaps he'd be bette
On Wed, Mar 26, 2003 at 10:13:40PM -0700, Uche Ogbuji wrote: > BTW, I find the idea of processing XML using simple regexen pretty hair > raising. Luckily that's not what Tim was talking about at all. I'm guessing you have not yet read about Perl 6 regular expressions :-) Perl 6 "regular expressions" are actually full-blown grammars, with an new and massivley clearer syntax. And that's what he referred to. It's more like having a more flexible and more powerful YACC interpreter. None the less, it's worth noting that one of the use cases for XML from the beginning was the "desparate perl hacker" who had to change, say, part number 1976 to 3072 in 100,000 documents without affecting dates, and had an afternoon to do it. That specific use case was achieved in practice for most people. If it sounds like a small achievement, consider (1) you can't easily do this given 100,000 mixed word processing documents (and with that many they will almost certainly not all be from the same version of the same program) (2) It wasn't trivial to do in SGML unless you had used an SGML editor or somehow "normalised" your data -- some examples: SGML XML <pn>1976</pn> <pn>1976</pn> <pn/1976/ <pn>1976</pn> <pn>1976</> <pn>1976</pn> <pn>1976</p> <p>....<pn>1976</pn></p> (The OMITTAG feature)  <p>1976</pn> <pn type="1976"> <pn type="1976"/> or <pn type="1976"></pn> Here, a more flexible input syntax makes life harder. Sometimes it makes life easier, too, especially for document authors. People have (separately) asked for all of these features (except possible DATATAG) in XML. But introducing any of them makes life harder for the Desparate Perl Hacker. So now we have a data representation that's a compromise -- it's not quite so nice, perhaps, for authors, but it's much nicer for programmers. The result of that has been massivley more application uptake, though, and many more authors who can now have vague feelings of resentment at the not-so-niceness :-) and that's the nature of compromise. Tim is right, I think (as so often) in that programming languages don't usually have a model that fits well with XML. Another way to look at it -- and he hinted at this in his 'blog -- is that XML is encouraging lots of programmers to manipulate the sorts of data that previously they would have ignored or left to someone else. It's part of the implication of massively increased uptake of SGML, or structured text: more people are dealing with structured text. Since the previous generations of programming languages didn't have this a data type, they flounder. I think this is part of why XSLT has been so successful. I'll be very interested to see if we get takeup of XML Query in the same way, which is a programming language with a non-XML syntax sort of like a cross between PL/1, SQL and Java in my mind, but with XML, XPath and strong typing included. It's also interesting watching some newer programming languages be developed with more structured (in the XML sense) data types, and corresponding operations. Some of the functional languages are well-placed to exploit this, although we're also seeing people jumping on the bandwagon by adding pointy brackets to existing languages and calling them "XML-based". Time will no doubt help us sort out the truly bad from the medicore (evolution does not favour the truly excellent) and we will march on. Liam -- Liam Quin, W3C XML Activity Lead, liam@w..., http://www.w3.org/People/Quin/ http://www.holoweb.net/~liam/ Ankh's list of IRC clients: http://www.valinor.sorcery.net/clients/
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