[xquery-talk] SequenceType matching in For/Some/Every expressions

[Michael Rys]

I would recommend that you file this as an error report at the W3C
Bugzilla site at  http://www.w3.org/Bugs/Public/  right now. 

Best regards
Michael

> -----Original Message-----
> From: talk-bounces at xquery.com 
> [mailto:talk-bounces at xquery.com] On Behalf Of Martin Probst
> Sent: Wednesday, September 28, 2005 7:01 AM
> To: talk at xquery.com
> Subject: [xquery-talk] SequenceType matching in 
> For/Some/Every expressions
> 
> Hi,
> I think there is a (somewhat minor) bug in the XQuery specification
> about sequence type matching. The grammar states:
> 
> [34]   ForClause         ::=    <"for" "$"> VarName 
> TypeDeclaration? ...
> [118]  TypeDeclaration   ::=    "as" SequenceType
> [119]  SequenceType      ::=    (ItemType OccurrenceIndicator?)
>                                 | <"empty-sequence" "(" ")">
> 
> and similar rules for Some, Every and Let. I think these rules should
> rather reference/descend directly into ItemType as the following
> statements do not make any sense to me (same for some&every):
> 
> for $x as xs:string* in ...
> for $x as xs:string+ in ...
> for $x as xs:string? in ...
> for $x as empty-sequence() in ...
> 
> The only thing that adds any semantic meaning is the empty-sequence()
> statement which I would interpret as "give an error if this yields
> something". But it's really cryptic and there are better ways to do
> this.
> 
> Am I missing something or is this an issue? The description 
> for for/let
> clauses doesn't mention occurrences at all.
> 
> Martin Probst
> X-Hive Corporation
> 
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