Re: [xsl] Confusion with the results of starts-with() and a non-string arg

["Bridger Dyson-Smith bdysonsmith@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Michael -

On Wed, Dec 12, 2018 at 4:20 PM Michael Kay mike@xxxxxxxxxxxx <
xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:

> true here means child::true, a reference to an element node. It's not the
> boolean constant true(). Saxon will generally give you a warning about this.
>
> You don't have an element named true, therefore child::true returns an
> empty sequence, and functions like starts-with treat an empty sequence the
> same as an empty string. Every string starts with the empty string, so the
> function returns true - or rather, true().
>
> Perfect - the child::true -> empty sequence -> empty string is exactly the
explanation that I needed.


> Michael Kay
> Saxonica
>
> Thanks!
Bridger

On 12 Dec 2018, at 21:10, Bridger Dyson-Smith bdysonsmith@xxxxxxxxx <
> xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hi all -
>
> In the process of trying to illustrate something for a coworker, I
> stumbled across some behavior that has me Very Confused. I would expect the
> starts-with function to return 'false' when the second argument is not a
> string, but the opposite happens: it returns 'true'.
>
> Can someone please help me understand what's happening here? Is this a
> sort of type casting, or something else?
>
> Thank you in advance.
> Best,
> Bridger
>
> source.xml
> ```
> <?xml version="1.0" encoding="UTF-8"?>
> <test>
>   <my-string>This Is My String</my-string>
> </test>
> ```
>
> test.xsl
> ```
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
>   xmlns:xs="http://www.w3.org/2001/XMLSchema";
>   exclude-result-prefixes="xs"
>   version="2.0">
>
>   <xsl:output method="xml" indent="yes" encoding="UTF-8"/>
>   <xsl:template match="@*|node()">
>     <xsl:copy>
>       <xsl:apply-templates select="@*|node()"/>
>     </xsl:copy>
>   </xsl:template>
>
>   <xsl:template match="my-string">
>     <xsl:if test="starts-with(.,true)">
>       <my-string-true>
>         <xsl:value-of select="starts-with(.,true)"/>
>         <xsl:text>###</xsl:text>
>         <xsl:value-of select="starts-with(.,'no')"/>
>       </my-string-true>
>     </xsl:if>
>   </xsl:template>
> </xsl:stylesheet>
> ```
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