Re: Simple solution? Pub. Idents. vs URN.

At 01:40 PM 11/28/96 -0800, Tim Bray wrote:
>I take the body of the above discussion (enjoyable though it is) 
>as strong evidence that for now, XML should stay with the two modes
>of addressing that it has built in: URL and ID/IDREF.  Every discussion
>of FPI's and UR[^L]'s that I have heard has quickly passed out of my
>comprehension and into a desolate area full of ringing assertions about
>document metaphysics and the eschatology of network addressing.  

There are simple principles at work. A URL is chosen based on where a
document is located. Sometimes people want to give documents more permanent
names. Within a closed system this can be done through FPIs. I suggest the
following wording:

"The PublicID is optional.

The Literal that follows the keyword PUBLIC is called the entity's public
identifier. It is a persistent name for the entity. User agents that have a
mechanism for resolving persistent names may use the public identifier to
locate the document. Other user agents may use the system identifier."

This is a simple "hook" for people who have solved the persistent name
problem within a particular system. SGML systems already support this hook,
of course. When Web systems have a global resolution, we will be ready. We
can register an FPI: namespace and register our documents within it.

It doesn't cost us anything to allow those who use public identifiers, or
who want to give it a shot to have a syntax for doing so.

> XML is not here to be a partisan of hypotheses about the way advanced 
> document processing ought to be done in the future; its goal is to specify
> a simple set of practices that (a) are comprehensible (b) are
> compliant with international standards and (c) work.

Within some (many!) systems, FPIs meet all of those goals.

 Paul Prescod