Convert TOML to DOCBOOK

Why Convert TOML to DOCBOOK?

Converting TOML configuration files to DocBook XML format is essential when configuration documentation needs to be integrated into large-scale technical publishing workflows. DocBook is the industry standard for technical documentation used by organizations like Red Hat, Fedora, O'Reilly Media, and many enterprise software companies for producing manuals, reference guides, and specification documents.

DocBook's semantic XML structure ensures that your configuration data is marked up with meaningful elements: sections, tables, code listings, and cross-references. This separation of content from presentation means the same DocBook source can generate HTML web pages, PDF manuals, EPUB e-books, and UNIX man pages through different XSLT stylesheets, providing maximum reach from a single conversion.

This conversion is particularly valuable for projects that already use DocBook for their documentation. By converting Cargo.toml, pyproject.toml, or application configuration files to DocBook, the configuration reference can be included directly in the existing documentation build pipeline using XInclude or entity references, ensuring that configuration documentation stays in sync with the rest of the project's documentation.

DocBook's validation capabilities (via RELAX NG or DTD schemas) ensure that the converted output is structurally correct and conforms to the standard. This level of rigor is important for organizations with documentation quality standards, regulatory compliance requirements, or formal publishing workflows where document structure must be verified before publication.

Key Benefits of Converting TOML to DOCBOOK:

• Industry Standard: DocBook is the de facto standard for technical publishing
• Multi-Format Output: Generate HTML, PDF, EPUB, and man pages from one source
• Semantic Markup: Meaningful XML elements for tables, code, and references
• Documentation Integration: Include in existing DocBook documentation sets
• Schema Validation: Verify structural correctness with RELAX NG/DTD
• XSLT Processing: Apply custom stylesheets for branded output
• Modular Composition: Use XInclude to embed in larger documents

Practical Examples

Example 1: Rust Project Documentation

Input TOML file (Cargo.toml):

[package]
name = "auth-service"
version = "1.5.0"
edition = "2021"
description = "OAuth2 authentication service"

[dependencies]
jsonwebtoken = "9.2"
argon2 = "0.5"
axum = "0.7"

Output DOCBOOK file (Cargo.xml):

<?xml version="1.0" encoding="UTF-8"?>
<article xmlns="http://docbook.org/ns/docbook"
         version="5.1">
  <title>Auth-Service Configuration</title>

  <section>
    <title>Package Information</title>
    <informaltable>
      <tgroup cols="2">
        <thead>
          <row><entry>Property</entry>
               <entry>Value</entry></row>
        </thead>
        <tbody>
          <row><entry>name</entry>
               <entry>auth-service</entry></row>
          <row><entry>version</entry>
               <entry>1.5.0</entry></row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>

  <section>
    <title>Dependencies</title>
    <itemizedlist>
      <listitem>jsonwebtoken 9.2</listitem>
      <listitem>argon2 0.5</listitem>
      <listitem>axum 0.7</listitem>
    </itemizedlist>
  </section>
</article>

Example 2: Application Configuration Reference

Input TOML file (config.toml):

[server]
host = "0.0.0.0"
port = 8443
tls_cert = "/etc/ssl/cert.pem"
tls_key = "/etc/ssl/key.pem"

[logging]
level = "info"
format = "json"
file = "/var/log/app.log"
max_size_mb = 100
rotate_count = 5

Output DOCBOOK file (config.xml):

<section xmlns="http://docbook.org/ns/docbook">
  <title>Server Configuration</title>
  <para>Network and TLS settings:</para>
  <informaltable>
    <tgroup cols="3">
      <thead>
        <row><entry>Key</entry>
             <entry>Value</entry>
             <entry>Type</entry></row>
      </thead>
      <tbody>
        <row><entry>host</entry>
             <entry>0.0.0.0</entry>
             <entry>string</entry></row>
        <row><entry>port</entry>
             <entry>8443</entry>
             <entry>integer</entry></row>
      </tbody>
    </tgroup>
  </informaltable>

  <section>
    <title>Logging Configuration</title>
    <note>
      <para>Logs rotate after 100MB,
      keeping 5 files.</para>
    </note>
  </section>
</section>

Example 3: Multi-Environment Setup

Input TOML file (environments.toml):

[[environments]]
name = "development"
url = "http://localhost:3000"
debug = true
database = "dev_db"

[[environments]]
name = "staging"
url = "https://staging.example.com"
debug = false
database = "staging_db"

[[environments]]
name = "production"
url = "https://api.example.com"
debug = false
database = "prod_db"

Output DOCBOOK file (environments.xml):

<article xmlns="http://docbook.org/ns/docbook">
  <title>Environment Configuration</title>

  <informaltable>
    <tgroup cols="4">
      <thead>
        <row>
          <entry>Environment</entry>
          <entry>URL</entry>
          <entry>Debug</entry>
          <entry>Database</entry>
        </row>
      </thead>
      <tbody>
        <row>
          <entry>development</entry>
          <entry>http://localhost:3000</entry>
          <entry>true</entry>
          <entry>dev_db</entry>
        </row>
        <row>
          <entry>staging</entry>
          <entry>https://staging.example.com</entry>
          <entry>false</entry>
          <entry>staging_db</entry>
        </row>
        <row>
          <entry>production</entry>
          <entry>https://api.example.com</entry>
          <entry>false</entry>
          <entry>prod_db</entry>
        </row>
      </tbody>
    </tgroup>
  </informaltable>

  <caution>
    <para>Debug mode must be disabled
    in production.</para>
  </caution>
</article>

Frequently Asked Questions (FAQ)

Q: What is DocBook?

A: DocBook is an XML vocabulary maintained by OASIS specifically designed for technical documentation. It provides semantic elements for books, articles, reference entries, code listings, tables, and more. DocBook separates content from presentation, allowing the same source to generate HTML, PDF, EPUB, and man page output through XSLT transformations.

Q: Who uses DocBook?

A: DocBook is widely used by the Linux community (Fedora, Red Hat, SUSE documentation), O'Reilly Media for technical books, FreeBSD documentation project, GNOME and KDE desktop environments, and many enterprise software companies. It is the standard for large-scale technical documentation projects that need multi-format output.

Q: How are TOML sections mapped to DocBook elements?

A: TOML [section] headers become DocBook <section> elements with <title> tags. Key-value pairs are converted to <informaltable> elements with rows and entries. Arrays become <itemizedlist> or <orderedlist> elements. Nested sections use nested <section> elements, maintaining the hierarchy.

Q: What output formats can I generate from the DocBook file?

A: DocBook XML can be transformed to HTML (single-page or chunked), PDF (via FOP or dblatex), EPUB (for e-readers), man pages (for UNIX systems), CHM (Windows help), and plain text. The DocBook XSL stylesheets provide comprehensive transformation support for all these formats.

Q: Can I include the DocBook output in an existing documentation project?

A: Yes! DocBook supports XInclude for modular document composition. You can include the converted TOML-to-DocBook output as a section or chapter in a larger DocBook book or article using <xi:include href="config.xml"/>. This is the standard approach for building large documentation sets from modular sources.

Q: Is the DocBook output valid XML?

A: Yes! The converter produces well-formed XML that conforms to the DocBook 5.1 schema. You can validate the output using RELAX NG schema validation with tools like xmllint, Jing, or Oxygen XML Editor. Valid DocBook ensures successful transformation with any compliant XSLT processor.

Q: How does DocBook compare to AsciiDoc?

A: DocBook is a verbose XML format ideal for large documentation projects with strict schema requirements. AsciiDoc is a lightweight text format that can output DocBook XML. Many projects use AsciiDoc as a friendlier authoring format that generates DocBook for processing. If you prefer a simpler markup, consider converting TOML to AsciiDoc instead.

Q: What tools do I need to process the DocBook output?

A: For HTML output, use xsltproc or Saxon with DocBook XSL stylesheets. For PDF, use Apache FOP or dblatex. For EPUB, use the DocBook EPUB3 stylesheets. Alternatively, tools like Pandoc can process DocBook input directly. Many Linux distributions include DocBook processing tools in their package repositories.