RE: Potential new issue: PSVI considered harmful

-----Original Message----- 
From: James Clark [mailto:jjc@xxxxxxxxxx] 
Sent: Sun 6/16/2002 11:29 PM 
To: www-tag@xxxxxx 
Cc: 
Subject: Re: Potential new issue: PSVI considered harmful


>(a) It makes documents less self-contained.
 
As are documents with DOCTYPE declarations, stylesheet PIs, and XML include 
locations. 

>(b) Applications that depend on a PSVI now require a very complex,
>heavy-weight schema validation process, rather than a relatively simple
>parsing process.
 
Applications that depend on the PSVI must have a reason for doing so. The above 
statement is like saying "applications that depend on the Java JVM/.NET CLR 
must now deal with non-deterministic finalization and the inability to manually 
manage memory instead of simply running machine code directly" 
 
So what? Applications that depend on the PSVI have made the *choice* to do so. 

>(c) Applications that depends on a PSVI must agree not only on the choice
>of schema language but also on the choice of mechanism to locate the
>schema. 
 
Interesting criticism especially since many consider it a beneficial feature of 
W3C XML Schema. So what alternative would you propose? 

>(d) The PSVI is not XML; this is the most insidious problem. 
 
> You cannot perform the PSVI infoset augmentation as a separate XML to XML 
> transformation. 
 
> when applications communicate using the XML infoset, they do not have to 
> share an address space, because
> there is a standard serialization of an XML infoset as XML, but this does not 
> apply with the PSVI. 
 
There are XML serializations of the PSVI. Granted, the ones I've seen are 
rather verbose but they do exist.