This repository is the remark markdown ecosystem monorepo. It ships four npm packages: remark-parse (markdown to mdast AST), remark-stringify (mdast AST to markdown), remark (a preconfigured unified processor with both), and remark-cli (a terminal interface). In practice, these packages are thin adapter plugins for unified: they attach parser/compiler functions to a unified processor, merge user settings from processor data, and expose extension hooks that other plugins use to add syntax support. The heavy CommonMark parsing and serialization is delegated to mdast-util-from-markdown and mdast-util-to-markdown, so the code here is intentionally small and focused on clean integration rather than reimplementation. The architecture is a workspace-based monorepo of ESM-only packages. Entry points are `remark()`, `unified().use(remarkParse)`, `unified().use(remarkStringify)`, and the `remark` CLI binary. The primary data flow is: markdown text -> unified parse -> mdast tree -> plugin transformations -> unified compile -> markdown text. Extension mechanisms use processor data fields (`micromarkExtensions`, `fromMarkdownExtensions`, `toMarkdownExtensions`), which keeps core packages stable while allowing the plugin ecosystem to grow without coupling. Maintenance is active: CI runs against multiple Node versions, tests downstream packages as canaries, and the codebase enforces strict TypeScript coverage. Technical drift is low: the packages target maintained Node versions, use current unified/micromark-based dependencies, and follow modern ESM conventions. The design is a strong example of building a stable, plugin-driven toolchain around an AST-processing core.
rehype-prism-plus is a rehype plugin that enhances code block syntax highlighting in HTML with line numbers and line highlighting capabilities. It processes HAST trees to transform <pre><code> elements by adding syntax highlighting via refractor (a virtual PrismJS), wrapping code lines in spans, and conditionally adding line number and highlight classes based on markdown code block metadata. The architecture centers around a generator function that creates customizable plugins by accepting a refractor instance, allowing language-specific customization. Key entry points include the default export (all languages), common.js (subset of languages), and generator.js (custom language sets). Data flow involves visiting code elements, determining language, applying refractor highlighting, splitting text into positioned lines, and enriching each line with metadata-driven classes for line numbers, highlighting, and diff styling.