[OSM-dev] XML Schema

[Frederik Ramm]

Hi,

Hugh Barnes wrote:
> I thought I saw a page some time ago which had a DTD in it, and someone 
> suggested we use RELAX NG instead to define the content model. Can't find it 
> now. That person was right. We'll have a lot more joy with it. It's also a 
> good idea to add attribute constraints etc (like the nonsensical no repeated 
> tag keys constraint) with Schematron.

All this is nice and might come in helpful for people starting with OSM, 
but it has to be remembered that currently anything you write could be 
in human language for all we care since neither servers nor clients 
actually use any kind of validation against any kind of coded schema.

So whatever you write is really only aimed at human beings wanting to 
understand the format/structure; the servers and clients might get out 
of sync with that at any time without anyone noticing.

Sorry if this was only stating the obvious but I have met people in the 
past who said, in disbelief, "but how can the server issue THIS when the 
DTD says THAT"? And I said, well, the server doesn't even know the DTD.

Bye
Frederik