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Re: Missing productions in Core BNF (WD 20 February 2004)?

From: Jerome Simeon <simeon@us.ibm.com>
Date: Wed, 25 Aug 2004 14:09:30 -0400
To: "Sievers, Jan" <j.sievers@sap.com>
Cc: "www-Ql (www-ql@w3.org)" <www-ql@w3.org>
Message-ID: <OFC23B3B9B.CD803954-ON85256EFB.006252A4-85256EFB.0063BC05@us.ibm.com>
Hi Jan,

Yes, that is a bug. Good catch. The connection:

ValueExpr -> PathExpr -> RelativePathExpr -> StepExpr -> FilterExpr -> 

was lost. It should be preserved in the XQuery core through:

ValueExpr -> StepExpr -> PrimaryExpr

There is no need for a FilterExpr which would just be a reference to 
PrimaryExpr, but
we need to introduce back the StepExpr as being the union of AxisStep or 

The corresponding grammar productions should be changed to the following:

ValueExpr  ::=  ValidateExpr | StepExpr
StepExpr  ::=  AxisStep | PrimaryExpr

This will be fixed in the next version of the Formal Semantics document.

- Jerome

"Sievers, Jan" <j.sievers@sap.com> 
Sent by: www-ql-request@w3.org
08/25/2004 11:36 AM

"www-Ql (www-ql@w3.org)" <www-ql@w3.org>

Missing productions in Core BNF (WD 20 February 2004)?

Hi everybody,

I am wondering if there are some productions missing in the Core BNF 
defined in "XQuery 1.0 and XPath 2.0 Formal Semantics" (Working Draft 20 
February 2004).

For instance there is no "StepExpr" or "FilterExpr" and the production [53 
(Core)] "PrimaryExpr ::= ..." is never used.

Is this a bug?
Or is there something special about the normalization rules?

Jan Sievers
Received on Wednesday, 25 August 2004 18:10:19 UTC

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