Thanks, Danny. This makes me wonder if there would be a place for an
extension function, call it xdmp:seq(), whose parameter would be a
sequence of items but whose return type would be treated as a single
item in a context like xdmp:eval(). So you could do something like
define variable $sequence as xs:integer* {
for $in in 1 to 1000 return $i
}
xdmp:eval(
'define variable $seq as xs:integer* external
$seq',
(xs:QName("seq"), xdmp:seq($sequence))
)
and get the desired output of 1, 2, 3, ... , 1000.
On Thu, 29 Nov 2007, Danny Sokolsky wrote:
> Hi David,
>
> Yes, that is correct, you cannot pass a sequence as the value of an
> external variable. As you surmised, the way to do that is to wrap the
> sequence values in XML and pass the node. Then you can use XPath to get
> the values from the node.
>
> Also, you can pass as many external variables as you need. They just
> need to be an even-length sequence alternating between QNames and items.
> For example, the following returns (1,2,3):
>
> xdmp:eval("define variable $a as xs:integer external
> define variable $b as xs:integer external
> define variable $c as xs:integer external
>
> $a, $b, $c", (xs:QName("a"), 1, xs:QName("b"), 2, xs:QName("c"), 3))
>
> Similarly, the following is how you might use a node to do something
> similar:
>
> xdmp:eval("define variable $a as node() external
>
> $a//a/text()", (xs:QName("a"), <foo><a>1</a><a>2</a><a>3</a></foo>))
>
> I hope that helps to clarify.
> -Danny
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of David
> Sewell
> Sent: Thursday, November 29, 2007 7:22 AM
> To: General XQZone Discussion
> Subject: [MarkLogic Dev General] Passing sequence as variable to
> xdmp:eval()?
>
> Is there a way to pass a sequence rather than a node or atomic value as
> an external variable to xdmp:eval()?
>
> This works, returning '9' as output:
>
> define variable $sequence as xs:integer* { (9) }
> xdmp:eval(
> 'define variable $seq as xs:integer* external
> $seq',
> (xs:QName("seq"), $sequence)
> )
>
> but this produces an XDMP-ARG error
>
> define variable $sequence as xs:integer* { (9, 11) }
> xdmp:eval(
> 'define variable $seq as xs:integer* external
> $seq',
> (xs:QName("seq"), $sequence)
> )
>
> because the second argument to xdmp:eval is parsed as
>
> (xs:QName("seq"), 9, 11)
>
> when $sequence is flattened.
>
> Is the only option in a case like this to wrap my sequence of integers
> in a constructed XML element and pass that as the external variable to
> xdmp:eval(), or am I missing something obvious?
>
>
--
David Sewell, Editorial and Technical Manager
ROTUNDA, The University of Virginia Press
PO Box 801079, Charlottesville, VA 22904-4318 USA
Courier: 310 Old Ivy Way, Suite 302, Charlottesville VA 22903
Email: [EMAIL PROTECTED] Tel: +1 434 924 9973
Web: http://rotunda.upress.virginia.edu/
_______________________________________________
General mailing list
[email protected]
http://xqzone.com/mailman/listinfo/general
