[xsl] Nesting a flat XML structure

Subject: [xsl] Nesting a flat XML structure
From: "ian.proudfoot@xxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 29 Oct 2018 18:13:52 -0000
Hello XSLT experts.

 

I have a need to transform flat xml that was sourced from a word processor
file and generate the implied structure. My efforts have been partially
successful for one level nesting but I'm finding it difficult to manage the
process for an arbitrary number of nested levels.

 

Here's a much simplified, but representative example of typical source XML:

 

<doc>

        <p style="h1">title text</p>

        <p style="para">body text</p>

        <p style="para">body text</p>

        <p style="bullet_level1">list text</p>

        <p style="bullet_level1">list text</p>

        <p style="bullet_level2">list text</p>

        <p style="bullet_level2">list text</p>

        <p style="bullet_level2">list text</p>

        <p style="h2">title text</p>

        <p style="para">body text</p>

        <p style="para">body text</p>

    </doc>

 

I need to generate the nested structure to look like similar to this (again
much simplified):

<doc>

        <section>

            <title>title text</title>

            <p>body text</p>

            <p>body text <ul>

                    <li>list text</li>

                    <li>list text<ul>

                            <li>list text</li>

                            <li>list text</li>

                            <li>list text</li>

                        </ul>

                    </li>

                </ul>

            </p>

            <section>

                <title>title text</title>

                <p>body text</p>

                <p>body text</p>

            </section>

        </section>

</doc>

 

There is no way to know in advance the level of nesting that may be needed.
The rules for nesting are provided by a separate mapping file. The mapping
file is used as the input to generate a document specific xslt file that
handles element naming and adds all of the necessary attributes. The format
and content of that mapping file are under my control but the source
documents are not.

 

My initial efforts used xsl:for-each-group with group adjacent to identify
and nest the first level and that works nicely, but I've got myself tied-up
in knots trying to work out how to make it work for any further nesting.
Perhaps I'm overthinking it? I tried to create a recursive template to do
the work, but that's where I got stuck. 

 

I'm using the latest version of Saxon via the version 9 API.

 

Thanks in advance.

Ian Proudfoot

Isle of Wight, UK 

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