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Re: Multiple and circular import/include

From: Bob Schloss <rschloss@us.ibm.com>
Date: Tue, 1 Mar 2005 15:17:04 -0500
To: vivek agarwal <vivekorama@gmail.com>
Cc: xmlschema-dev@w3.org
Message-ID: <OFAB49F6CF.A3DF33A0-ON85256FB7.006EC01A-85256FB7.006F6D26@us.ibm.com>


      It is not an error to include the same schema document as the target
of multiple <include> or <import> directives.

      Circular <include> or <import> directives are permitted.

      This is my mental model:

1. The processor fetches your top-level schema document, and then keeps
fetching any other schemas which are referenced through directives,
transitively, but whenever it sees a directive targetting something it has
already fetched, it doesn't fetch it again.  At the end of this process,
the "actual schema" to be used for processing now exists in memory, having
been merged from 1...n individual documents having the XML representation
of XML Schema.

2. Then the processor starts doing whatever it plans to do (validation of
instance documents during parsing, generating Data Binding code, generating
UI forms, or whatever).

      Because of subtleties associated with <redefine>, for the sanity of
anyone who may have to maintain what you design, I would try to avoid
circular redefines.

            Good Luck,

Scalable XML Infrastructure
IBM Thomas J Watson Research Center
Yorktown Heights, New York, USA

             vivek agarwal                                                 
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                                       Multiple and circular               
             03/01/2005 01:41          import/include                      
             Please respond to                                             
               vivek agarwal                                               


I have a question on multiple and circular import/include each, if
somebody could help.

Is it an error to import/include a schema more than once?
A import/includes B1 and B2.
Both B1, and B2, import/includes C.
What is the expected behaviour of the processor in such a case?

Are circular import/includes allowed?
A import/includes B, and B import/includes A?
What is the expected behaviour of the processor in such a case?

Received on Tuesday, 1 March 2005 20:17:41 UTC

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