I’m new to xslt and I’m trying to use some custom C# code in XSLT3.
While searching I’ve seen it was done that way in XSLT1 :

<xsl:variable name="CurrentDateTime"
    select="userCSharp:DateCurrentDateTime()" />
 ...
    </xsl:template>
    <msxsl:script language="C#" implements-prefix="userCSharp">
    <![CDATA[
        public string DateCurrentDateTime()
        {
        DateTime dt = DateTime.Now;
        string curdate = dt.ToString("yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
        string curtime = dt.ToString("T", System.Globalization.CultureInfo.InvariantCulture);
        string retval = curdate + "T" + curtime;
        return retval;
        }
        ]]>
</msxsl:script>

This is a sample code, mine would be using a custom dll.

but it doesn’t seem to work that way in XSLT3 and most topics I found are about using xslt3 within .Net, not the other way around.

https://www.w3.org/TR/xslt-30/#extension-functions

https://www.saxonica.com/html/documentation12/extensibility/extension-functions-CS/ext-fns-N.html

But I can’t understand how it’s supposed to be done.

Would anyone have a simple example?