Re: [xsl] Re: Performance observation.

However where-populated can't doing the same job as try catch here because
the stylesheet just errored with an attempt to create a namespace node with
a blank namespace uri.

On Tue, Sep 8, 2020 at 7:37 AM Ihe Onwuka <[email protected]> wrote:

> xsl:where-populated fluctuates as high as the try catch but at best there
> is no performance penalty.
>
>
> On Tue, Sep 8, 2020 at 6:19 AM Michael Kay mike-JkSD5nQpfvpWk0Htik3J/[email protected] <
> xsl-list-service-VWJlPdIPk9umXcTjhJAOxCoMnp2j79Jp@public.gmane.org> wrote:
>
>> I'm slightly suprised by the performance effect but it depends how often
>> the pattern is matched, and what other patterns are present in the
>> stylesheet. Certainly putting complex logic into patterns can be risky from
>> a performance point of view.
>>
>> How about using xsl:where-populated rather than xsl:try?
>>
>> Michael Kay
>> Saxonica
>>
>> On 8 Sep 2020, at 08:16, Ihe Onwuka <[email protected]> wrote:
>>
>> The goal is to create a namespace node if the value of xsi:type is a
>> QName.
>>
>> The code here simulates the situation
>>
>> https://xsltfiddle.liberty-development.net/a9HjZj
>>
>> The problem is that this fails if the select evaluates to the empty
>> string.
>>
>>  <xsl:template match="@xsi:type">
>>          <xsl:namespace name="{substring-before(.,':')}"
>> select="$schemas/thing/@targetNamespace"/>
>>          <xsl:next-match/>
>>    </xsl:template>
>>
>> Now in the real code the select is actually a key retrieval so looks more
>> like this
>>
>>    <xsl:template match="@xsi:type">
>>          <xsl:namespace name="{substring-before(.,':')}"
>> select="key('myKey',.,$schemas)/@targetNamespace"/>
>>          <xsl:next-match/>
>>    </xsl:template>
>>
>> So in order to avoid failure I tried this
>>
>>      <xsl:template match="@xsi:type[
>> key('myKey',.,$schemas)/@targetNamespace => normalize-space()]">
>>          <xsl:namespace name="{substring-before(.,':')}"
>> select="key('myKey',.,$schemas)/@targetNamespace"/>
>>          <xsl:next-match/>
>>    </xsl:template>
>>
>> now that works but quadrupled the execution time of the stylesheet.
>>
>> Doing it with try catch
>>
>>       <xsl:template match="@xsi:type">
>>          <xsl:try>
>>              <xsl:namespace name="{substring-before(.,':')}"
>> select="key('myKey',.,$schemas)/@targetNamespace"/>
>>              <xsl:catch/>
>>          </xsl:try>
>>          <xsl:next-match/>
>>    </xsl:template>
>>
>> is a teenie bit quicker.
>>
>> Overall execution time is still tolerable so posting this as an
>> observation.
>>
>> For the  XSL list
>>
>> Is there a way to code
>>
>>    <xsl:template match="@xsi:type[
>> key('myKey',.,$schemas)/@targetNamespace => normalize-space()]">
>>          <xsl:namespace name="{substring-before(.,':')}"
>> select="key('myKey',.,$schemas)/@targetNamespace"/>
>>          <xsl:next-match/>
>>    </xsl:template>
>>
>> without repeating the code for the key access thats on the template rule
>> predicate inside the template rule.
>>
>>
>>
>>
>>
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>

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