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Re: [xsl] Type of a variable containing values of mixed types

Subject: Re: [xsl] Type of a variable containing values of mixed types
From: "Michael Kay mike@xxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 13 Apr 2015 11:59:11 -0000

The XQuery/XSLT type system treats sequences as homogenous, so you can only
constrain the item type and the cardinality (except where you're dealing with
elements validated against a schema, in which case the item type of the parent
can constrain the sequence of children according to the content model of an
XSD complex type).

In XQuery 3.0/XSLT 3.0 you can make greater use of union types:

  <xs:simpleType name="integer-or-date">
    <xs:union memberTypes="xs:integer xs:date"/>

<xsl:variable name="var" as="int-or-date*" select="...."/>

but in 2.0 you have to declare such a sequence with as="xs:anyAtomicType*"/>

Michael Kay
+44 (0) 118 946 5893

On 13 Apr 2015, at 11:39, Jorge . chocolate.camera@xxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

> Hi,
> I only seldom write XSLT (and specifically only 2.0) so there are many
> aspects of it that I am still not familiar with. After reading
> <http://www.ibm.com/developerworks/library/x-schemaawarexslt/index.html>
> I am forcing myself to declare the type of variables, parameters and,
> sometimes, templates. I have immediately seen the benefit of it as
> transformations I thought were simple and bug-free fail all over the
> place revealing cases I did not account for.
> How can I enforce that a variable contains a particular bunch of mixed
> types? Say:
>    <xsl:variable name="MY_VAR" as="">
>        <xsl:value-of select="42"/>
>        <xsl:value-of select="13"/>
>        <xsl:value-of select="hello"/>
>    </xsl:variable>
> Is there a way to enforce, with the attribute `as`, that the variable
> contains a series of integers and a string (or, even, particularly 2
> integers and 1 string) or else have the transformation fail?
> I am using Saxon-HE
> Jorge

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