Plugins case study: mdBook preprocessors

5 months ago

mdBook is a tool for creating books from Markdown files, popular in the Rust ecosystem.
It supports a plugin mechanism for modifying book output, usable with any programming language.
Plugins can be registered in the book.toml file and are executed as sub-processes.
Discovery is explicit, requiring plugins to be listed in the configuration.
Registration involves invoking the plugin twice to check support and process the book.
Hooks are coarse-grained, processing the entire book in JSON format.
Rust plugins have access to additional utilities via the Preprocessor trait.
Renderers (backends) process the book similarly to preprocessors but produce final output like HTML.

Hasty Briefsbeta