A discriminated-union-based HTML/SVG element tree that provides a type-safe, composable way to generate HTML fragments. It is used throughout the formatting libraries and can be extracted as a standalone HTML builder for any F# project needing programmatic HTML generation without string concatenation.

A collection of F# active patterns (e.g., `(|StartsWith|_|)`, `(|DelimitedWith|_|)`, `(|BracketDelimited|_|)`) that enable composable, declarative string and list parsing. These patterns are reusable across any project that needs lightweight parsing without a full parser combinator library.

Implements smart line-wrapping for F# type signatures by leveraging the F# Compiler Service's own parser. It produces human-readable, width-constrained signature output without sacrificing correctness. This component can be reused in any F# tooling (e.g., IDE plugins, documentation generators) that renders type signatures.

Defines a complete F# type model for Jupyter notebook files (nbformat v4), including cells, metadata, and output types. It can be extracted and used independently for reading, manipulating, or generating .ipynb files in any F# application.

A navigation menu builder that takes a list of page entries and generates a nested HTML menu using template substitution. The logic for constructing ancestors, grouping by directory, and generating active/inactive states is self-contained and reusable for any static site generator.

Defines the interface for a development server that watches source files, incrementally rebuilds only changed pages, and serves them from memory with a dependency graph for cache invalidation. The pattern of event-based file watching + dependency tracking + lazy in-memory serving is reusable for other build tools.