Re: More namespaces perversion

Peter Murray-Rust (peter@ursus.demon.co.uk)
Wed, 07 Oct 1998 13:22:32


At 12:45 06/10/98 -0400, Eric Hellman wrote:
>David Brownell wrote:
>>In summary: all namespaces (ever) do is provide a layer of indirection.
>>Their meanings change over at least time. When you use namespaces you
>>need to consider what that change will do to your applications.
>
>
>It seems to me that the current NameSpaces draft adds TWO things to XML.
>
>1. A layer of indirection is added.
>
>2. A mechanism to associate XML elements with URI's is added.
>
>It seems to me that not much attention has been paid to the things that can
>usefully be done with that second function. After all, there is no role
>specified for the Namespace URI.

When one is writing element-oriented software there *may* needs to be a
means of associating Java classes with elements. Thus if I have
<C:molecule>... <M:eqn>... </M:eqn>... </C:molecule>
where C is the prefix for CML and M for MathML I need an absolute handle.
If my code requires a search for MathML elements embedded in CML elements
it can only be done through the URI - the prefixes are volatile.

>
>But consider how different tools might make use of the Namespace URI.
>
>If I were adding Namespace support to a structured editor, I'd present the
>Namespace URI as a hyperlink button in my user interface - it's trivial to
>do, can't hurt anything.

The thing that's killing me at present is this:

having read in an XML document to JUMBO2, edited it in some way, how to I
add namespaces awareness to thew output. I have to decide where it's
required (i.e. analyse the potential scoping, have a table of current
namespaces, and make sure I don't have prefix clashes). None of it's rocket
science, but all the little bits add up to a large amount of frustration.

P.

Peter Murray-Rust, Director Virtual School of Molecular Sciences, domestic
net connection
VSMS http://www.nottingham.ac.uk/vsms, Virtual Hyperglossary
http://www.venus.co.uk/vhg