XPath to display available tags non-recursively (using xmllint in a shell script)

I am trying to construct an XPath argument for use in an xmllint program (used in a Bash shell script) that will return a list of available tags in a tag (while not listing subtags).

Here is the kind of XML I have:

<functionInformation>
    <class>
        setup
    </class>
    <description>
        This is a natural language description of this function.
    </description>
    <prerequisiteFunctions>
        myFunction1
        myFunction2
    </prerequisiteFunctions>
    <prerequisitePrograms>
        myProgram1
        myProgram2
    </prerequisitePrograms>
</functionInformation>

      

        
        
        
      

    

This XML is stored in the Bash variableInformation.

The result I would like to use when using xmllint in this XML is the following:

class
description
prerequisiteFunctions
prerequisitePrograms

      

        
        
        
      

    

I should note that I would like the tags to return in a non-recursive way (I don't want all the available tags or subtitles to be listed).

I can access the information in tags using xmllint in this way:

descriptionFunctionInformation="$(echo "${functionInformation}"\
                | xmllint --xpath '/functionInformation/description/text()' -\
                | xargs -i echo -n "{}")"

      

        
        
        
      

    

Could you please point me in the right direction, how can I build XPath (or something similar) to return the information I need?