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Re: Cross-references among included schema documents

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Mon, 27 Sep 2004 08:55:28 +0100
To: "Michael Kay" <mhk@mhk.me.uk>
Cc: <xmlschema-dev@w3.org>
Message-ID: <f5bfz54403z.fsf@erasmus.inf.ed.ac.uk>

You've put your finger on a weakness in the REC -- the prevasive
impact of the necessity of allowing for late binding was imperfectly
realised in the prose.  The bit you quote from 4.2.1 [1]:

  "As discussed in Missing Sub-components (§5.3) [2], ˇQNameˇs in XML
  representations may fail to ˇresolveˇ, rendering components
  incomplete and unusable because of missing subcomponents. During
  schema construction, implementations must retain ˇQNameˇ values for
  such references, in case an appropriately-named component becomes
  available to discharge the reference by the time it is actually
  needed."

is meant to have a universal impact.  So, somewhat informally, I'd say
that in your example the inclusion of B into A results in a schema,
some of whose references are unresolved.  Once C is integrated, we get
an enlarged schema, and resolution becomes possible.

The XML Schema WG is at work to make this cleaner, clearer and more
systematic in Schema 1.1

ht

[1] http://www.w3.org/TR/2004/PER-xmlschema-1-20040318/#compound-schema
[2] http://www.w3.org/TR/2004/PER-xmlschema-1-20040318/#conformance-missing
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
    2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
            Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
                   URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
Received on Monday, 27 September 2004 07:55:34 UTC

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