Re: [xml-dev] HTML5 and almost no namespaces

[Michael Kay <mike@saxonica.com>]

> Are you suggesting that current XML namespaces are bad for every known
> uses of XML?
>

There has been a great deal of discussion of the namespace problem on 
this list over the years, and I'm a bit reluctant to spend a lot of time 
covering the ground again. But I think the problems with namespaces 
reduce to a number of general categories:

* Learning problems for beginners: the specifications are non-intuitive, 
hard to understand, and inconsistent; for example, namespace 
declarations sometimes behave like attributes and sometimes don't.

* Usability problems even for experienced users: the context-sensitivity 
of namespace prefixes makes it hard to get transformations right, and 
means that simple operations like cut-and-paste can produce incorrect 
results.

* Difficulties for implementors of tools: if you're writing XML 
processing software such as an XSLT or XQuery engine, or a schema 
processor or XML editor, then getting namespaces right absorbs a 
ridiculous proportion of your time; in consequence, there are many tools 
out there that don't get it right, which creates more difficulties for 
users. The complexity is unnecessary. Most of it derives from the fact 
that the namespace design introduces context-sensitivity (in-scope 
namespaces), which means that fragments of XML cannot be interpreted in 
isolation of where they appear.

* Interoperability problems: the fact that XML element names are not 
simple strings makes it difficult to define clean interfaces with other 
environments, for example data interchange with other formats, or 
programming language APIs.

The basic problem of resolving ambiguous local names could have been 
solved without these complexities.

Michael Kay
Saxonica