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Re: [ANN] XQuery prototype

From: james anderson <james.anderson@setf.de>
Date: Mon, 14 May 2001 12:53:31 +0200
Message-ID: <3AFFB929.79F5B5D0@setf.de>
To: xml-dev@lists.xml.org
CC: Michael Rys <mrys@microsoft.com>, xmldb@xmldb.org, www-xml-query-comments@w3.org

while one welcomes that someone makes public a demonstration of and an
apparently implementable description for a concrete xml-query language,
the cited document demonstrates numerous differences with the the
available working draft for xml-query.

i was hoping to find clarity on rather simple matters like the ambiguity
between names and variables, but return from a cursory examination more
dazed and confused than enlightened.

while some of the differences would appear to be necessary:
- that operator precedence is achieved through expression levels
- provision for the projection operator in the concrete syntax

and others are reasonable interim restrictions:
- ordering constraints on declaration and query expressions

others appear either inexplicable, gratuitous, simply counter to the
working draft:
- the QName form
- the namespace, default namespace declarations
- chages to structured data type declarations ('schema')
- changes to function declaration syntax
- a 'list' datatype
- multiple bindings for 'for' and 'let' expressions
- quantification
- attribute expression syntax
- element expression syntax
- side-effects / DMLStatements
- an apparently complete adoption of xpath syntax: for example '//' and
  '[' <predicate-exp ']'

for an implementation which is associated with one of the draft's
authors, and which claims, that

> [t]he goal of the prototype implementation is to follow the public working
> drafts of the W3C XML Query working group while trying to avoid "inside"
> knowledge about how something is supposed to work. Thus, you will find
> some XQuery features not implemented because their implementation would
> have required certain assumptions that are not documented in the
> specification.

these manifestations are surprising. i make no claims as to either their
correctness, not their worthiness. i'm just wondering whether there are
additional documents which account for the demonstation's discrepancies
with respect to the public documents? is there some public forum, where
discrepancies are being discussed? is this really XQuery?

Michael Rys wrote:
> 
> We are please to announce that the XQuery prototype demonstrated at XML
> DevCon in New York in April is now available for people to play with.
> You can reach it either via a link from http://msdn.microsoft.com/xml
> <http://msdn.microsoft.com/xml>  or direct via http://131.107.228.20
> <http://131.107.228.20> . The prototype currently follows the  February
> 15, 2001 working draft (http://www.w3.org/TR/xquery
> <http://www.w3.org/TR/xquery> ) and will be updated to the next working
> draft within weeks after the next working draft's publication.
>
Received on Monday, 14 May 2001 06:50:01 GMT

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