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

Anja,

I am not sure I understand what you mean by 'sequences of AxisStep'. Do 
you mean
expressions like 'a/b/c' ?

'/' in XPath/XQuery is compiled in the core using a combination of 
iteration using FLWOR
expression and sorting by document order, so it doesn't appear 'as is' 
after normalization
into the XQuery Core.

- Jerome





"Bog, Anja" <[email protected]> 
Sent by: [email protected]
08/26/2004 09:13 AM

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"'[email protected]'" <[email protected]>
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Subject
AW: Missing productions in Core BNF (WD 20 February 2004)?






Hi everybody,
 
there's another issue I am wondering about now: If you produce StepExpr 
from ValueExpr
 
>ValueExpr -> StepExpr -> PrimaryExpr 
 
how will you produce Sequences of AxisSteps like they are usual for 
PathExpressions?
 
Tks,
Anja
-----Ursprüngliche Nachricht-----
Von: [email protected] [mailto:[email protected]] Im Auftrag von 
Jerome Simeon
Gesendet: Mittwoch, 25. August 2004 20:10
An: Sievers, Jan
Cc: www-Ql ([email protected])
Betreff: Re: Missing productions in Core BNF (WD 20 February 2004)?


Hi Jan, 

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

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

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 
PrimaryExpr. 

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. 

Best, 
- Jerome 



"Sievers, Jan" <[email protected]> 
Sent by: [email protected] 
08/25/2004 11:36 AM 


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"www-Ql ([email protected])" <[email protected]> 
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Subject
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?

Thanks,
Jan Sievers