xml-dev - RE: interoperability (was Re: Obfuscating XML with namespaces)

[Jonathan.Robie@SoftwareAG-USA.com]

Title: RE: interoperability (was Re: Obfuscating XML with namespaces)

XML makes syntax a no-brainer, but it does not make semantics a no-brainer. In XML, the syntax is transparent, because each instance wears its parse tree glued firmly to its data. That's all XML was designed to do, and it does it very well. There are certainly some interoperability glitches if one party uses a well-formed parser and the other party uses a validating parser, but if both use the same class of parser things work pretty well.

I agree with Joshua - XML really does make things *much* easier. I remember writing libraries to handle various data formats, and it was tedious busiwork, and the resulting software was also often unreliable. Think about how many incompatible implementations of RTF there are. Remember that before XML, data formats were generally specified with text and examples, and rich data formats were hard to describe precisely.

With XML, two parties can agree on an exchange format, and they already have software that knows how to validate it, transform it to other formats, etc. They do *not* automatically get software that tells how one vocabulary relates to another, explains the meaning behind the structure, etc., but we didn't have that before XML either.

XML solves the problem of syntactic interoperability. It does not solve the problem of semantic interoperability. It was never designed to. Frankly, I'm not sure what a good solution to this problem looks like - has there every been a good general solution in other realms of software?

Now that XML has made syntax so much easier, a lot of people are very eager to tackle the semantics problem. But let's not blame XML for the fact that semantics are hard!

Jonathan