XSLT 2.0: Filtering through nodes / text with analyze-string but needing to also grab XML tags

Question

I'm working through my first major XSLT project, and am a bit of a novice, so please be patient with my ignorance.

Our group is working on a transform of existing XMLs to an entirely different tagging system. I have devised a system of processing the MathType callouts (signified by "${TEXT}" ) using Analyze-String, but I'm having difficulty determining what I should do with code like the ital tags (signified by the "I" tags), which need to be kept in the result code.

I tried using copy-of in the non-matching-substring, but that appears to not work. Of course, value-of gets me everything except the ital tags.

I realize the variable ($stemString) is superfluous at this point. I was going along that path thinking I might be able to come up with something that would allow copy-of to process, but so far, no luck.

Sample Code:

<stem>What is the value of <I>f</I>(<I>x</I>) when ${##A112800eqn01:3}</stem>

My current XSLT:

<?xml version="1.0" encoding="UTF-8"?>

<xsl:template match="node()|@*">
    <xsl:copy>
        <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="assessmentItem">

<!--SNIP-->

    <xsl:apply-templates select="stemArea/stem"/>

<!--SNIP-->

</xsl:template>

<xsl:template match="stem">

    <xsl:variable name="stemString">
        <xsl:copy-of select="./* | ./text()"/>
    </xsl:variable>

    <xsl:choose>

        <!--Tests for empty stems that aren't art callouts-->
        <xsl:when test=". = '' and @type!='art'"></xsl:when>
        <xsl:when test=". = ' ' and @type!='art'"></xsl:when>

        <!--Test for art callouts-->
        <xsl:when test="@type='art'"><p><img alt="{@loc}" height="10" id="{@loc}" label="" longdesc="normal" src="{@loc}" width="10"/></p></xsl:when>

        <!--Test for boxed text-->
        <xsl:when test="@style='box' or @style='boxL'"><p><span label="Tag_7">
            <xsl:copy-of select="./* | ./text()"></xsl:copy-of>
        </span></p></xsl:when>

        <xsl:otherwise><p>

            <!--Are MathType tokens present in stem?-->
            <xsl:analyze-string regex="(\$\{{.+\}})" select="$stemString">

                <!--If MathType tokens are in stem, do the following-->
                <xsl:matching-substring>

                    <xsl:analyze-string regex="(\$\{{)(##.+[eqn|art]\d+)([^a-zA-Z0-9]?.*\}})" select=".">
                        <xsl:matching-substring>
                            <img alt="{regex-group(2)}" height="10" id="{regex-group(2)}" label="" longdesc="normal" src="{regex-group(2)}" width="10"/>
                        </xsl:matching-substring>
                        <xsl:non-matching-substring>
                            <xsl:text>ERROR</xsl:text>
                        </xsl:non-matching-substring>
                    </xsl:analyze-string>

                </xsl:matching-substring>

                <!--No MathType tokens in string-->
                <xsl:non-matching-substring>
                    <xsl:value-of select="."/>
                </xsl:non-matching-substring>

            </xsl:analyze-string>
        </p></xsl:otherwise>

    </xsl:choose>

</xsl:template>

Desired Output:

<p>What is the value of <I>f</I>(<I>x</I>) when <img alt="##A112800eqn01" height="10" id="##A112800eqn01" label="" longdesc="normal" src="##A112800eqn01" width="10"/></p>

What I'm getting:

<p>What is the value of f(x) when <img alt="##A112800eqn01" height="10" id="##A112800eqn01" label="" longdesc="normal" src="##A112800eqn01" width="10"/></p>

Anyone have any ideas for how to proceed?

@Martin Honnen: Thank you for the response. Your code solves the error.

However, I have an additional issue. When there is more than one MathType callout in a stem, it causes an error. I am sure that the cause is my regex not capturing everything properly, but I have hammered on this for a while to no avail. Below I will illustrate the issue I'm having.

Sample Code:

<stem type="text">What is the value of <I>f</I>(<I>x</I>) when ${##A112800eqn01:3}, and ${##A112800eqn02:3} is 3.</stem>

Desired Output:

<p>What is the value of <I>f</I>(<I>x</I>) when <img alt="##A112800eqn01" height="10" id="##A112800eqn01" label="" longdesc="normal" src="##A112800eqn01" width="10"/>, and <img alt="##A112800eqn02" height="10" id="##A112800eqn02" label="" longdesc="normal" src="##A112800eqn02" width="10"/> is 3.</p>

What I'm getting:

<p>What is the value of <I>f</I>(<I>x</I>) when <img alt="##A112800eqn01:3}, and ${##A112800eqn02" height="10" id="##A112800eqn01:3}, and ${##A112800eqn02" label="" longdesc="normal" src="##A112800eqn01:3}, and ${##A112800eqn02" width="10"/> is 3.</p>

Answer 1

Don't match on an element and then put xsl:choose inside of the template to distinguish further, instead simply write templates for the different elements or elements with certain attribute values.

And if you want to use analyze-string then do that in a template of a text node, not in the template of an element containing mixed content:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="node()|@*">
    <xsl:copy>
        <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="assessmentItem">

<!--SNIP-->

    <xsl:apply-templates select="stemArea/stem"/>

<!--SNIP-->

</xsl:template>

<xsl:template match="stem[. = '' and @type!='art'] | stem[. = ' ' and @type != 'art']"/>

<xsl:template match="stem[@style='box' or @style='boxL']">
  <p><span label="Tag_7"><xsl:apply-templates/></span></p>
</xsl:template>

<xsl:template match="stem[.//text()[matches(., '\$\{.+\}')]]">
  <p>
    <xsl:apply-templates/>
  </p>
</xsl:template>

<xsl:template match="stem//text()[matches(., '\$\{.+\}')]">
  <xsl:analyze-string regex="(\$\{{)(##.+[eqn|art]\d+)([^a-zA-Z0-9]?.*\}})" select=".">
    <xsl:matching-substring>
      <img alt="{regex-group(2)}" height="10" id="{regex-group(2)}" label="" longdesc="normal" src="{regex-group(2)}" width="10"/>
    </xsl:matching-substring>
    <xsl:non-matching-substring>
        <xsl:value-of select="."/>
    </xsl:non-matching-substring>
  </xsl:analyze-string>
</xsl:template>

</xsl:stylesheet>

With that stylesheet, when applied to the input

<stem>What is the value of <I>f</I>(<I>x</I>) when ${##A112800eqn01:3}</stem>

I get the result

<p>What is the value of <I>f</I>(<I>x</I>) when <img alt="##A112800eqn01" height="10" id="##A112800eqn01" label="" longdesc="normal" src="##A112800eqn01" width="10"/></p>

The above is meant as a suggestion on how to approach your stylesheet design, it is likely not a complete solution as I don't have much input samples to test and don't know the input XML and text format you are trying to process.

I would probably implement

<xsl:template match="stem[. = '' and @type!='art'] | stem[. = ' ' and @type != 'art']"/>

as

<xsl:template match="stem[not(normalize-space()) and @type!='art']"/>

instead but I have mainly tried to show how to structure the stylesheet with templates and how to match on a descendant text node of stem to ensure the analyze-string does not swallow elements nodes inside stem.

As for your edited input requirement, I have changed the regular expression to use non-greedy matching (.*?), so with the code below you should be able to match on several patterns in a stem to create several img elements:

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="node()|@*">
    <xsl:copy>
        <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
</xsl:template>

<xsl:template match="assessmentItem">

<!--SNIP-->

    <xsl:apply-templates select="stemArea/stem"/>

<!--SNIP-->

</xsl:template>

<xsl:template match="stem[. = '' and @type!='art'] | stem[. = ' ' and @type != 'art']"/>

<xsl:template match="stem[@style='box' or @style='boxL']">
  <p><span label="Tag_7"><xsl:apply-templates/></span></p>
</xsl:template>

<xsl:template match="stem[.//text()[matches(., '\$\{.+?\}')]]">
  <p>
    <xsl:apply-templates/>
  </p>
</xsl:template>

<xsl:template match="stem//text()[matches(., '\$\{.+?\}')]">
  <xsl:analyze-string regex="(\$\{{)(##.+?[eqn|art]\d+)([^a-zA-Z0-9]?.*?\}})" select=".">
    <xsl:matching-substring>
      <img alt="{regex-group(2)}" height="10" id="{regex-group(2)}" label="" longdesc="normal" src="{regex-group(2)}" width="10"/>
    </xsl:matching-substring>
    <xsl:non-matching-substring>
        <xsl:value-of select="."/>
    </xsl:non-matching-substring>
  </xsl:analyze-string>
</xsl:template>

</xsl:stylesheet>