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Tim Bray Says RELAX
twofish writes to tell us that Sun's Tim Bray (co-editor of XML and the XML namespace specifications) has posted a blog entry suggesting RELAX NG be used instead of the W3C XML Schema. From the blog: "W3C XML Schemas (XSD) suck. They are hard to read, hard to write, hard to understand, have interoperability problems, and are unable to describe lots of things you want to do all the time in XML. Schemas based on Relax NG, also known as ISO Standard 19757, are easy to write, easy to read, are backed by a rigorous formalism for interoperability, and can describe immensely more different XML constructs."
It also works really, really well with the nXML mode for emacs.
Finally, XML schemas in a way that are not verbose, ugly and unreadable. And if you do need one of the older schema languages there are translators from RelaxNG available.
Relax NG is a great example of the triumph of Design-by-Inspired-Individuals vs. Design-by-Committee.
In The State of XML, Edd Dumbill explains the secret behind the success of Relax NG:
-Don
Take a look and feel free: http://www.PieMenu.com
I was at SGML '96 where XML was first announced, and was one of those people who went home and wrote a (non-validating) XML parser over the weekend, based on the draft spec. I've used both DTDs and XML Schemas and can say without question that schemas are actually a bigger pain to work with than DTDs. DTDs were bad enough, but schemas have been a major step backwards, adding complexity without adding the features one actually needs.
Some years ago I wrote a code generator that used DTDs as the data modelling language. I sold it to the company I was working for at the time and someone I had no control over re-wrote it use schemas because they were "simpler". The result had major bugs and dropped features, not entirely due to schema-related problems, although it is worth noting that the "simplifications" included handling schemas in completely incorrect ways, because if you handled them correctly they could not do the job. I created a new generator from scratch last year and tried to do thing "properly" with schemas. It was essentially impossible, and I wound up creating a custom XML-based language use as input.
At the time there was no Relax NG standards process, so I stayed clear of it. But it has the blessing of James Clarke too (author of the SP SGML parser and the expat XML parser.) So it is probably worth another very hard look.
Blasphemy is a human right. Blasphemophobia kills.
You could certainly make XML vastly more compact if you had some table of tags mapped to 2-byte codes. You're not the first to have such an idea, and I and others will be happy to use it... as soon as you've got it standardized, implemented, and as widely accepted as ASCII. Point being, I, and everyone I've never even met who will ever touch some particular XML file, already has a text editor.
We also all have some way of decompressing files in several standard compression formats, which will squash the XML down to the same size as your custom scheme, if storage space is an issue, which it generally isn't. There's all manner of custom schemes one can use to do various things better when one defines the platform. When you want to inter-opperate well, you need to use the capabilities that already exist on only semi-known systems.
Generally we don't actually make customers use new specialized tools. We take advantage of the new specialized tools they already have. I'm pretty sure not one of my customers ever got a browser to read my documentation; I wrote it in HTML because they've all got browsers already.