Re: [docbook] URN for Simplified DocBook and DocBook XML

[Jirka Kosek <jirka at kosek dot cz>]

Oliver Fischer wrote:
> Jirka Kosek wrote:

> According to the standard is a URN also a valid URI - IMHO. Or did I 
> misinterpret the docs I read? A SystemLiteral is URI and both URL and 
> URN are URIs. So why not use a URN als SystemLiteral?

Of course, you can use URN as system identifier. But it has some 
drawbacks. Imagine that your DocBook file will have following DOCTYPE:

<!DOCTYPE book SYSTEM "urn:x-docbook:dtd:v4.2">

> I could use catalog files to resolve the URN. Or not?

You will be able to process the DocBook file with correct catalog. But 
what will your friend do with this file without appropriate catalogs? 
Using URL as system identifier is much better when you want to maintain 
easy interchange of your documents.

The best you can do is to use both FPI (public identifier) and URL as 
system identifier. Then catalog files can do FPI based redirection to 
local resources and URL is there for folks without proper catalog 
machinery.

But if interoperability is not your concern and you know that you will 
always use catalog capable tools, then you can safely use URNs as system 
identifier.

				Jirka

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  Jirka Kosek  	
  e-mail: jirka@kosek.cz
  http://www.kosek.cz

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