Namespaces, prefixes, and URIs

John Cowan cowan at
Sat Apr 10 23:10:12 BST 1999

David Brownell scripsit:

> I didn't see the words "deserve to lose" in the spec.  What I
> saw was a statement that if you use namespaces (TBS) your docs
> might need to change.  The XML 1.0 spec has not been revised
> (incompatibly) to require conformance to the namespace spec.

It says:

# [A]uthors should not use the colon in XML names except as part of
# name-space experiments[.]

So there is a SHOULD NOT prohibition against bogus colons of the
first kind (non-namespace).

Bogus colons of the second kind (namespace experiments) may
indeed have to be changed, but why must the DOM support non-W3
namespace experiments?  The uses of colons in namespaces are
now prescribed, and other uses are proscribed.

> In general, my background makes me believe that incompatible
> changes to foundational specs (e.g. XML 1.0) are, as a rule,
> pure unadulterated evil.
> One never quite knows what could get broken by such changes ...
> though it's usually "someone else's software" not your own.
> Now there's a dynamic to think about.

You're right in general.  But the XML Rec goes to some pains to say
that uses of : are either deprecated or may have to be changed,
putting people on notice pending the namespace Rec.

> Didn't namespaces break architectural forms compatibility?
> Minimally the <?IS10744:arch ...?> PI doesn't conform.

The alternative form <?IS10744 arch ...?> works fine;
I'll get the XAF maintainers to add support for it.

> And aren't there SGML applications using colons as name
> characters?  Perhaps permitting such SGML systems to
> migrate to XML isn't "really important" any more.

Are colons NAMESTRT characters in the reference concrete syntax?

John Cowan					cowan at
		e'osai ko sarji la lojban.

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