Re: [xsl] best practices for using XSLT modes

["Martin Honnen martin.honnen@xxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Am 04.12.2019 um 07:42 schrieb Mukul Gandhi gandhi.mukul@xxxxxxxxx:
> Hi all,
> B  B I imagine that, using XSLT modes is useful. I've been trying
> different XSLT approaches for solving a class of XML transformation
> problems.
>
> Below is an example of what I've tried (I present an XML document, two
> different XSLT stylesheets [non schema aware] to process the XML
> document, and an identical transformation output with both the
> presented stylesheets):
>
> XML document:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <root>
> B  B <a val="-1"/>
> B  B <a val="-4"/>
> B  B <a val="5"/>
> B  B <a val="3"/>
> B  B <a val="2"/>
> </root>
>
> Stylesheet 1:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
> B  B  B  B  B  B  B  B  B  B  B  B  B version="3.0">
>
> B  B  <xsl:output method="xml" indent="yes"/>
>
> B  B  <xsl:template match="root">
> B  B  B  B <result>
> B  B  B  B  B  <xsl:apply-templates select="a[number(@val) gt 0]"
mode="gt0"/>
> B  B  B  B  B  <xsl:apply-templates select="a[number(@val) lt 0]"
mode="lt0"/>
> B  B  B  B </result>
> B  B  </xsl:template>
>
> B  B  <xsl:template match="a" mode="gt0">
> B  B  B  <val><xsl:value-of select="@val"/>: positive</val>
> B  B  </xsl:template>
>
> B  B  <xsl:template match="a" mode="lt0">
> B  B  B  <val><xsl:value-of select="@val"/>: negative</val>
> B  B  </xsl:template>
>
> </xsl:stylesheet>
>
> Stylesheet 2:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
> B  B  B  B  B  B  B  B  B  B  B  B  B version="3.0">
>
> B  B  <xsl:output method="xml" indent="yes"/>
>
> B  B  <xsl:template match="root">
> B  B  B  B <result>
> B  B  B  B  B  <xsl:apply-templates select="a[number(@val) gt 0]"/>
> B  B  B  B  B  <xsl:apply-templates select="a[number(@val) lt 0]"/>
> B  B  B  B </result>
> B  B  </xsl:template>
>
> B  B  <xsl:template match="a[number(@val) gt 0]">
> B  B  B  <val><xsl:value-of select="@val"/>: positive</val>
> B  B  </xsl:template>
>
> B  B  <xsl:template match="a[number(@val) lt 0]">
> B  B  B  <val><xsl:value-of select="@val"/>: negative</val>
> B  B  </xsl:template>
>
> </xsl:stylesheet>
>
> Both of above stylesheets, achieve the same thing and generate
> following output:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <result>
> B  B <val>5: positive</val>
> B  B <val>3: positive</val>
> B  B <val>2: positive</val>
> B  B <val>-1: negative</val>
> B  B <val>-4: negative</val>
> </result>
>
> The intent of mentioned transformations, is that the result is little
> reorganization of the input.
>
> My questions are following,
> Which of above mentioned XSLT transformations, is better over the
> other, particularly considering the use of modes (conceptually &
> possibly wrt to any other factors)?


That example seems to be too simple or artificial to show the value of
modes. In general I think modes have their value if you need to process
the same type of nodes twice e.g. once for generating a table of
contents and the second time for splitting into result documents. Or, in
the context of XSLT 3, if you need to separate processing steps working
with streamed input nodes from ones using grounded ones.