Re: [xsl] strong typed variable with restriction ?

[Michel Hendriksen <michel.hendriksen@xxxxxxxxx>]

Or add a message in an xsl:otherwise...

<xsl:message terminate="yes|no">

  <!-- Content:template -->

</xsl:message>

On Wed, Feb 2, 2011 at 12:21 PM, Michael Kay <mike@xxxxxxxxxxxx> wrote:
> There seem to be two separate questions here.
>>
>> I have a xsl:function which :
>> - must return a element()
>> - has a string param "foobar".
>>
>> I typed $foobar as xs:string but I'd like to restrict the possible values
>> to "foo" or "bar".
>> I know it's possible to define such a constrain in a xsd schema, but is
>> there a way to do that in xpath2 ?
>
> You can declare a local type in your stylesheet:
>
> <xsl:stylesheet xmlns:fb="urn:local:foobar" ....>
>
> <xsl:import-schema>
> <xs:schema targetNamespace="urn:local:foobar">
> <xs:simpleType name="foobarType">
> <xs:restriction base="xs:string">
> <xs:enumeration value="foo"/>
> <xs:enumeration value="bar"/>
> </xs:restriction>
> </xs:simpleType>
> </xs:schema>
> </xsl:import-schema>
>
> <xsl:function name="igs:get-css-rule" as="element()">
> <xsl:param name="foobar" as="fb:foobarType"/>
>  ....
>
> Note that when calling the function, you can't pass a string directly: you
> will have to cast ot to fb:foobarType first.
>
>
>>
>>
>> This typing is important because the returned element() is selected from a
>> xsl:choose on $foobar value (with no otherwise) :
>>
>> My code looks like :
>> <xsl:function name="igs:get-css-rule" as="element()">
>> <xsl:param name="foobar" as="xs:string"/> <!--(foo|bar)-->
>> <xsl:choose>
>> <xsl:when test="$foobar='foo'">
>> <xsl:sequence select="igs:get-my-foo-item()"/>
>> </xsl:when>
>> <xsl:when test="$css='bar'">
>> <xsl:sequence select="igs:get-my-bar-item()"/>
>> </xsl:when>
>> </xsl:choose>
>> </xsl:function>
>>
>> And I get such a parsing  error on my xslt :
>>  XTTE0570: Conditional expression: If none of the conditions is satisfied,
>> an empty
>>  sequence will be returned, but this is not allowed  [...]
>
> Typing the parameter unfortunately won't solve this problem. The processor
> isn't clever enough to work out that the implicit "otherwise" branch will
> never be executed, so it will still report a type error to the effect that
> the implicit "otherwise" branch returns a value (namely the empty sequence)
> which doesn't conform to the required return type of the function. (There
> has been some suggestion that Saxon's type checking here is too
pessimistic;
> the type error should be raised dynamically if this branch is taken, not
> statically). The easiest way around this is probably to change the last
> xsl:when condition to an xsl:otherwise.
>
> Michael Kay
> Saxonica