Convert DOCBOOK to TOML

Why Convert DocBook to TOML?

Converting DocBook to TOML is useful when you need to extract configuration data, metadata, or structured settings from technical documentation and express them in a minimal, human-readable configuration format. DocBook documents often contain tables and lists that define application settings, system parameters, and deployment configurations that can be directly converted to TOML key-value pairs.

TOML (Tom's Obvious, Minimal Language) was created by Tom Preston-Werner in 2013 specifically to be an unambiguous, human-friendly configuration format. Unlike YAML, which has well-documented parsing pitfalls (the "Norway problem"), TOML's specification ensures that values are always parsed as intended. It is the standard configuration format for Rust (Cargo.toml) and Python (pyproject.toml) projects.

The conversion process maps DocBook's hierarchical sections to TOML table headers ([section.subsection]), and table data to key-value pairs. Lists become TOML arrays, and nested structures use dotted keys or nested table syntax. The converter infers data types from content, converting numeric values to integers or floats and boolean-like values to true/false.

This conversion is particularly valuable for teams that document their application configurations in DocBook and want to generate actual TOML configuration files from those specifications. It eliminates the manual step of translating documented settings into configuration files, ensuring that deployed configurations match their documentation exactly.

Key Benefits of Converting DocBook to TOML:

• Configuration Generation: Create config files directly from documented specifications
• Human-Readable: TOML is designed to be easy to read and edit
• Type Safety: TOML enforces explicit typing for values
• Rust/Python Standard: Generate Cargo.toml and pyproject.toml from docs
• No Ambiguity: TOML parsing is deterministic, unlike YAML
• Comment Preservation: DocBook descriptions become TOML comments
• Documentation Sync: Keep configs aligned with technical documentation

Practical Examples

Example 1: Application Configuration

Input DocBook file (config-spec.xml):

<article xmlns="http://docbook.org/ns/docbook">
  <title>Application Configuration</title>
  <section>
    <title>Server</title>
    <informaltable>
      <tgroup cols="2">
        <tbody>
          <row><entry>host</entry><entry>0.0.0.0</entry></row>
          <row><entry>port</entry><entry>8080</entry></row>
          <row><entry>workers</entry><entry>4</entry></row>
          <row><entry>debug</entry><entry>false</entry></row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>
  <section>
    <title>Database</title>
    <informaltable>
      <tgroup cols="2">
        <tbody>
          <row><entry>url</entry><entry>postgres://localhost/mydb</entry></row>
          <row><entry>pool_size</entry><entry>10</entry></row>
        </tbody>
      </tgroup>
    </informaltable>
  </section>
</article>

Output TOML file (config.toml):

# Application Configuration

[server]
host = "0.0.0.0"
port = 8080
workers = 4
debug = false

[database]
url = "postgres://localhost/mydb"
pool_size = 10

Example 2: Rust Project Metadata

Input DocBook file (project-spec.dbk):

<article xmlns="http://docbook.org/ns/docbook">
  <title>Package Metadata</title>
  <section>
    <title>Package</title>
    <informaltable><tgroup cols="2"><tbody>
      <row><entry>name</entry><entry>my-tool</entry></row>
      <row><entry>version</entry><entry>0.3.1</entry></row>
      <row><entry>edition</entry><entry>2021</entry></row>
    </tbody></tgroup></informaltable>
  </section>
  <section>
    <title>Dependencies</title>
    <informaltable><tgroup cols="2"><tbody>
      <row><entry>serde</entry><entry>1.0</entry></row>
      <row><entry>tokio</entry><entry>1.28</entry></row>
    </tbody></tgroup></informaltable>
  </section>
</article>

Output TOML file (Cargo.toml):

# Package Metadata

[package]
name = "my-tool"
version = "0.3.1"
edition = "2021"

[dependencies]
serde = "1.0"
tokio = "1.28"

Example 3: Deployment Settings

Input DocBook file (deploy-config.xml):

<section xmlns="http://docbook.org/ns/docbook">
  <title>Deployment Configuration</title>
  <section>
    <title>Logging</title>
    <informaltable><tgroup cols="2"><tbody>
      <row><entry>level</entry><entry>info</entry></row>
      <row><entry>format</entry><entry>json</entry></row>
    </tbody></tgroup></informaltable>
  </section>
  <section>
    <title>Monitoring</title>
    <itemizedlist>
      <listitem><para>prometheus</para></listitem>
      <listitem><para>grafana</para></listitem>
      <listitem><para>alertmanager</para></listitem>
    </itemizedlist>
  </section>
</section>

Output TOML file (deploy.toml):

# Deployment Configuration

[logging]
level = "info"
format = "json"

[monitoring]
tools = ["prometheus", "grafana", "alertmanager"]

Frequently Asked Questions (FAQ)

Q: What is TOML format?

A: TOML (Tom's Obvious, Minimal Language) is a configuration file format created by Tom Preston-Werner in 2013. It uses key-value pairs organized into sections (tables) with explicit data typing. TOML is designed to be human-readable and maps unambiguously to hash tables. It is the standard config format for Rust (Cargo.toml) and Python (pyproject.toml) projects.

Q: How does DocBook structure map to TOML?

A: DocBook sections map to TOML table headers ([section_name]). Tables with key-value data become TOML key-value pairs. Nested sections use dotted keys or sub-table syntax ([parent.child]). Lists become TOML arrays. DocBook title elements become TOML comments. The converter infers appropriate data types (string, integer, float, boolean) from the content.

Q: How are data types determined?

A: The converter analyzes each value and assigns the appropriate TOML type. Pure numeric values become integers or floats. "true" and "false" become booleans. ISO date/time strings become TOML datetime values. Everything else becomes a quoted string. This type inference ensures the TOML output can be parsed correctly by TOML libraries in any programming language.

Q: Can I use the output as a Cargo.toml file?

A: If your DocBook document describes a Rust project configuration with appropriate sections (package, dependencies, build, etc.), the output can serve as a starting point for a Cargo.toml file. The structure will need to follow Cargo's expected schema. The converter preserves section names and key-value pairs that you can refine for Cargo compatibility.

Q: What happens to DocBook narrative content?

A: Narrative paragraphs, admonitions, and descriptive text that do not represent key-value data are converted to TOML comments (# prefix). This preserves the context and documentation alongside the configuration data. Section titles become section header comments, and descriptions of individual settings appear as inline comments above the relevant key-value pairs.

Q: How are DocBook lists converted to TOML?

A: DocBook itemized lists and ordered lists are converted to TOML arrays. Simple text lists become arrays of strings (items = ["a", "b", "c"]). Lists with structured content may become arrays of inline tables. The converter determines the most appropriate TOML representation based on the complexity and nesting of the list content.

Q: How does TOML compare to YAML for configuration?

A: TOML and YAML both serve as configuration formats, but TOML offers stronger type safety and unambiguous parsing. YAML's flexible syntax can lead to surprising behavior (e.g., "no" being parsed as false, version numbers as floats). TOML requires explicit quoting for strings and has a simpler specification. YAML is better for deeply nested data, while TOML excels for flat or moderately nested configurations.

Q: Can I convert TOML back to DocBook?

A: Yes, our converter supports TOML to DocBook conversion. The reverse process parses TOML tables into DocBook sections, key-value pairs into table rows, and arrays into itemized lists. Comments are converted to DocBook paragraphs. This round-trip capability enables documentation-as-code workflows where configuration and documentation stay synchronized.