Schematron to check the location of given class attribute values

Question

Schematron to check the location of given class attribute values

48 Views Asked by nico At 28 February 2024 at 13:54

I’d like to create a Schematron schema that validates:

That if elements at /html/body/main/div/div have an optional class attribute, it contains one of the cat1 or cat2 values in any case.
That if elements not at /html/body/main/div/div have an optional class attribute, it does not in any case contain one of the values cat1 or cat2.

Here’s a valid example:

<html xmlns="http://www.w3.org/1999/xhtml">
    <head></head>
    <body>
        <main>
            <div class="name">
                <div class="cat1 cat3"> <!— Other values are acceptable as long as cat1 or cat2 is present. —>
                    <div></div>
                </div>
                <div class="cat2">
                    <div></div>
                </div>
                <div> <!— No class attribute is OK —>
                    <div></div>
                </div>
            </div>
        </main>
    </body>
</html>

And an invalid example:

<html xmlns="http://www.w3.org/1999/xhtml">
    <head></head>
    <body>
        <main>
            <div class="name cat1"> <!— cat1 not allowed here —>
                <div class="cat3"> <!— cat1 or cat2 missing —>
                    <div></div>
                </div>
                <div class="cat2">
                    <div class="cat2"></div> <!— cat2 not allowed here —>
                </div>
                <div class=""> <!— Empty class attribute is not OK —>
                </div>
            </div>
        </main>
    </body>
</html>

Here’s what I’ve got so far. The XPath query //*[not(self::html/body/main/div/div)] doesn’t work. It also returns nodes at /html/body/main/div/div.

<schema xmlns="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt2">
    <pattern id="test">
        <rule context="//*[not(self::html/body/main/div/div)]">
            <assert test="
                    not(contains(@class, ’cat1’)) and
                    not(contains(@class, ’cat2’))
                    " role="error"> 
                        The class cannot contain 
                        "<value-of select="@class"/>". 
            </assert>
        </rule>
    </pattern>
</schema>

Original Q&A

There are 3 best solutions below

Martin Honnen On 28 February 2024 at 15:23

I would try

<schema xmlns="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt3">
    <ns prefix="xhtml" uri="http://www.w3.org/1999/xhtml"/>
    <let name="cats" value="('cat1', 'cat2')"/>
    <let name="divs" value="/xhtml:html/xhtml:body/xhtml:main/xhtml:div/xhtml:div"/>
    <pattern>
        <rule context="*[not(. intersect $divs)]/@class">
          <assert test="every $cat in $cats satisfies not(contains-token(., $cat))">@class '<value-of select="."/>' contains one of $cats values '<value-of select="$cats"/>'</assert>
        </rule>
        <rule context="$divs">
            <assert test="@class = $cats">@class value '<value-of select="@class"/>' not equal to $cats '<value-of select="$cats"/>'</assert>
        </rule>
    </pattern>
</schema>

I have assumed xslt3 binding as these days Schematron is usually compiled with a current version of Saxon and these support XSLT 3.

Most of it should work as xslt2 as well, not sure about contains-token.

Mads Hansen On 28 February 2024 at 15:56

The XPath for your context is not right. If you want it to evaluate for any/all elements //* then the predicate of self::html/body/main/div/div would only match on the root node and none of the elements.

If you are trying to assert that the matched element is not /html/body/main/div/div then you could try:

<rule context="//*[not(generate-id(.) = /html/body/main/div/div/generate-id())]">

**Nico Kutscherauer** · Accepted Answer · 2024-02-29T09:25:24.187000

Martins Answer works (except of a small mistake) but it is unnecessarily complex in my opinion. If you want it simpler or needs to use XSLT2, you can do it in this way:

<schema xmlns="http://purl.oclc.org/dsdl/schematron" queryBinding="xslt2">
    <ns prefix="xhtml" uri="http://www.w3.org/1999/xhtml"/>
    <let name="cats" value="('cat1', 'cat2')"/>
    <pattern>
        <rule context="/xhtml:html/xhtml:body/xhtml:main/xhtml:div/xhtml:div[@class]">
            <assert test="tokenize(@class, '\s') = $cats">Missing class <value-of select="string-join($cats, ' or ')"/>.</assert>
        </rule>
        <!--this rule will only checks elements which are not checked by the rule above-->
        <rule context="*[@class]">
            <let name="class" value="@class"/>
            <!-- Just use report instead of assert to get the opposite check result. -->
            <report test="tokenize($class, '\s') = $cats"
                >Used forbidden class: <value-of select="$cats[. = tokenize($class, '\s')]"/>.</report>
        </rule>
    </pattern>
</schema>

Schematron to check the location of given class attribute values

There are 3 best solutions below

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