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RE: Permit (greedy) conflicting wildcards

From: Michael Kay <mike@saxonica.com>
Date: Tue, 10 Apr 2007 10:51:08 +0100
To: "'Michael Kay'" <mike@saxonica.com>, <noah_mendelsohn@us.ibm.com>
Cc: "'Pete Cordell'" <petexmldev@tech-know-ware.com>, <xmlschema-dev@w3.org>
Message-ID: <00f101c77b55$c3826dd0$6401a8c0@turtle>

> If one took the "late binding" principle to extremes, then it 
> would be impossible to do anything useful at query 
> compilation time, which would obviously be unacceptable. So 
> it's a question of finding the right level of late binding.

Replying to myself, there is actually another approach, which is to allow
the schema to change, and to automatically recompile queries whose
assumptions about the schema have become out of date. Saxon actually does a
bit of that too, in a small way. 

But you wouldn't want to take this to extremes, for example by not reporting
static errors in the query on the off-chance that by the time the query is
executed, the schema will have changed sufficiently to make the query valid.

Reporting static errors in a query at run-time because changes to the schema
have made the query invalid is also rather unsatisfactory, because you're
reporting the error to the person running the query and not to the person
who wrote it (or to the person who changed the schema).

Michael Kay
Received on Tuesday, 10 April 2007 09:51:17 UTC

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