Architecture

Lumis has three core components: languages, themes, and formatters. Source code flows through a pipeline that turns it into styled output.

Pipeline

source code
    |
    v
Tree-sitter parser (language grammar + highlight queries)
    |
    v
highlighted tokens (text + scope + byte range)
    |
    v
theme (scope -> color/style mapping)
    |
    v
formatter (tokens + styles -> HTML / ANSI / BBCode Scoped / custom output)

1. Tree-sitter parses the source into a concrete syntax tree
2. Highlight queries map tree nodes to scope names (keyword, function, string, etc.)
3. The theme maps scopes to colors and styles (foreground, background, bold, italic)
4. The formatter turns each token + style into the final output format

Components

Languages

110+ Tree-sitter grammars. Each language has:

• a parser (compiled to native code for Rust, WASM for JavaScript, Elixir, and the CLI)
• highlight queries (mostly from nvim-treesitter)
• injections for nested languages (e.g., CSS and JavaScript inside HTML)

Dynamic runtimes receive parser and queries together in a self-contained, independently versioned @lumis-sh/wasm-* package. A small stable catalog maps language IDs to package names, and one Tree-sitter-compatible npm range applies to the whole catalog. The CDN resolves that range; the package supplies current queries and the exact integrity-pinned parser. Updating one language within the supported series does not require a runtime package release.

Themes

250+ themes extracted from Neovim colorschemes. Each theme is a JSON file mapping Tree-sitter scopes to styles. Themes have a name and appearance (light or dark).

Formatters

Convert highlighted tokens into output:

Formatter	Output
HTML Inline	<span style="color: #e5c07b;">
HTML Linked	<span class="l-keyword">
HTML Multi-Themes	<span style="--lumis-light:#333; --lumis-dark:#ccc;">
Terminal	ANSI escape codes
BBCode Scoped	[keyword-function]main[/keyword-function]

Crate structure

lumis-core        internal: language detection, theme/style logic, formatter behavior
lumis             public Rust API, Tree-sitter adapter, builder patterns
lumis-cli         CLI binary
lumis-build       build-time code generation
lumis-wasm-runtime shared Tree-sitter WASM engine, lazy registry, and bounded worker pool

Package layers

• The Elixir package (packages/elixir/lumis) uses a small Rustler NIF with a shared Wasmtime engine and loads parser WASM per language.
• The JavaScript runtime package (packages/javascript/lumis) uses a native addon over that same Wasmtime runtime on Node, and web-tree-sitter in browsers, with the same per-language parser assets either way.
• The integration packages (packages/javascript/markdown-it-lumis and packages/javascript/rehype-lumis) build on top of that JavaScript runtime for Markdown and HAST pipelines.