SSG — Scala Static Site Generator

A cross-platform Scala 3 static site generator targeting JVM, Scala.js, and Scala Native — without external binary dependencies. Built by porting battle-tested libraries to idiomatic Scala 3.

Warning

Work in progress - components are ported from other languages, but have not yet been composed into a working static site generator.

Modules

Module	Source Library	Language	Purpose	Status
ssg-md	flexmark-java 0.64.8	Java	Markdown engine	5889 tests
ssg-liquid	liqp 0.9.2	Java	Liquid template engine	863 tests
ssg-sass	dart-sass 1.99.0	Dart	SASS/SCSS compiler	13865/13902 sass-spec (99.7%)
ssg-minify	jekyll-minifier 0.2.2	Ruby	HTML/CSS/JS/JSON minification	121 tests
ssg-js	terser 5.46.1	JavaScript	JavaScript compiler/minifier	2518 tests
ssg-katex	KaTeX 0.16.45	TypeScript	Math typesetting engine	648 tests
ssg-mermaid	Mermaid 11.0.0	TypeScript	Diagramming engine (31 types)	543 tests
ssg-highlight	tree-sitter	C/Rust	Syntax highlighting	73 grammars
ssg-graphviz	—	—	Graphviz DOT renderer (4 layout engines)	99 tests
ssg-graphs-commons	—	—	Shared graph layout + SVG infrastructure	—
ssg-data-commons	—	—	Shared data view abstractions	—
ssg-commons	—	—	Shared cross-platform utilities	—
ssg-site	—	—	Site pipeline (SSG-native glue)	—
ssg	—	—	Aggregator (depends on all above)	—

All completed modules pass tests on JVM, Scala.js, and Scala Native.

Building

Requires: JDK 21+, sbt 1.12+, Scala 3.8.4

# Compile all modules on default (JVM) platform
re-scale build compile

# Compile on all platforms (JVM + JS + Native)
re-scale build compile --all

# Run tests for a specific module
re-scale test unit --module ssg-liquid

# Full 3-platform verification
re-scale test verify

Architecture

Each module ports a source library to Scala 3 with these principles:

• No external binary dependencies — pure Scala on all platforms
• Cross-platform — JVM, Scala.js, Scala Native from the same source
• Idiomatic Scala 3 — enum, boundary/break, opaque types, no return
• Original tests ported — comprehensive munit test suites

ssg-md (Markdown)

Ports flexmark-java's modular Markdown parser with 20+ extensions (tables, TOC, footnotes, admonitions, emoji, etc.).

ssg-liquid (Liquid Templates)

Ports liqp's Liquid template engine with a hand-written lexer/parser (replacing ANTLR), 58 filters, 17 tags/blocks, and an extensible flavor system (Jekyll default, open to Shopify/Cobalt.rs/MkDocs configurations).

Key replacements:

• ANTLR → hand-written 3-mode lexer + recursive descent parser
• Jackson → LiquidSupport trait
• strftime4j → DateTimeFormatter via scala-java-time polyfill

ssg-sass (SASS/SCSS Compiler)

Ports dart-sass — the reference implementation of the Sass language — to Scala 3. Full compilation pipeline: SCSS/Sass/CSS parsing, evaluation, module system (@use/@forward), @extend resolution, and CSS serialization.

Key features:

• All 17 color spaces (oklch, lab, display-p3, etc.) with gamut mapping
• Full module system (@use, @forward, @import) with configuration
• @extend selector resolution with identity-based trimming
• 130+ built-in functions across 8 modules (color, math, string, list, map, meta, selector)
• NativeMath FFI (JVM calls native C libm via JEP 454) for IEEE 754 precision parity with dart-sass
• Indented syntax (.sass) via faithful state-machine parser

The 37 non-passing tests are: 32 whitespace mismatches against older sass-spec expected outputs (our output matches dart-sass 1.99), and 5 tests that dart-sass itself marks as :todo:.

ssg-minify (HTML/CSS/JS/JSON Minification)

Ports jekyll-minifier as pure Scala minification functions for HTML, CSS, JavaScript, and JSON. Full HTML minification (comment removal, whitespace collapsing, attribute optimization, inline CSS/JS compression). Pluggable JsCompressor trait allows using the basic whitespace-only minifier or the full Terser engine from ssg-js.

ssg-js (JavaScript Compiler/Minifier)

Ports Terser (fork of UglifyJS) — a full JavaScript compiler with:

• ES2020+ parser (recursive descent, ~130 AST node types)
• Code generator (minified and beautified output)
• Scope analysis and variable mangling
• Compressor with 25+ per-node optimizations (dead code elimination, constant folding, statement tightening)
• Pure Scala, cross-platform (no regex lookahead/backreference)

Usage: ssg.js.Terser.minifyToString("var x = 1 + 2;") or integrate with ssg-minify via ssg.TerserJsCompressorAdapter.

ssg-katex (Math Typesetting)

Ports KaTeX — the fast LaTeX math typesetting library — to Scala 3. Server-side rendering: LaTeX expression in, HTML+MathML string out.

Key features:

• Full LaTeX parser with macro expansion (180+ built-in macros)
• 57 parse node types, 45 function implementations (fractions, roots, accents, etc.)
• HTML output builder with font metrics and delimiter sizing
• MathML output for accessibility
• 42 environment implementations (array, matrix, aligned, cases, CD, etc.)

Usage: ssg.katex.KaTeX.renderToString("\\frac{1}{2}")

ssg-mermaid (Diagramming Engine)

Ports Mermaid — the text-based diagramming library — to Scala 3. Server-side SVG rendering: diagram text in, SVG string out.

Key features:

• All 31 diagram types: flowchart, sequence, class, state, ER, pie, gantt, timeline, mindmap, git graph, architecture, and 20 more
• Custom SVG builder replacing D3.js (no browser DOM required)
• dagre Sugiyama graph layout algorithm (rank assignment, crossing minimization, coordinate assignment)
• 12 node shapes, 7 curve types, 9 arrow markers
• 4 themes (default, dark, forest, neutral)
• Hand-written parsers for all 31 diagram grammars (replacing Jison/Langium)

Usage: ssg.mermaid.Mermaid.render("graph TD\\n A-->B")

ssg-graphviz (Graphviz DOT Renderer)

Server-side Graphviz DOT rendering: DOT text in, SVG string out. Original SSG implementation (not a port of an external library), reusing the graph layout and SVG infrastructure from ssg-graphs-commons.

Key features:

• Full DOT language parser (recursive descent, 13 grammar productions)
• 4 layout engines: dot (dagre/Sugiyama hierarchical), neato (Kamada-Kawai spring/force-directed), circo (circular), twopi (radial tree)
• Node shapes: ellipse, box/rect, circle, diamond, plaintext
• DOT attribute support: styling, labels, colors, fonts, rankdir
• Arrow markers for directed graphs, dashed/dotted edge styles

Usage: ssg.graphviz.Graphviz.render("digraph { A -> B -> C }")

ssg-highlight (Syntax Highlighting)

Tree-sitter-based syntax highlighting supporting 73 programming language grammars. Unlike the other modules (which are source-level ports), ssg-highlight wraps tree-sitter via platform-specific FFI: JEP 454 (Panama) on JVM, WASM bindings on Scala.js, and direct C interop on Scala Native.

Project Structure

ssg/
├── ssg-commons/        Shared cross-platform utilities
├── ssg-graphs-commons/ Shared graph layout + SVG infrastructure
├── ssg-md/             Markdown engine (flexmark-java port)
├── ssg-liquid/         Liquid template engine (liqp port)
├── ssg-sass/           SASS/SCSS compiler (dart-sass port)
├── ssg-minify/         HTML/CSS/JS/JSON minification (jekyll-minifier port)
├── ssg-js/             JavaScript compiler/minifier (Terser port)
├── ssg-katex/          Math typesetting engine (KaTeX port)
├── ssg-mermaid/        Diagramming engine (Mermaid port, 31 diagram types)
├── ssg-graphviz/       Graphviz DOT renderer (4 layout engines)
├── ssg-highlight/      Syntax highlighting (tree-sitter, 73 grammars)
├── ssg/                Aggregator module
├── original-src/    Reference sources (git submodules, not compiled)
├── .rescale/        re-scale project config + data
├── docs/            Architecture and conversion guides
└── project/         sbt build configuration

Documentation

• CLAUDE.md — project conventions and tooling
• docs/contributing/ — conversion guides, code style, type mappings
• docs/contributing/cross-platform-regex.md — regex limitations on Scala Native/JS
• docs/architecture/ — module design, build structure, port status

License

SSG source code is licensed under the Apache License 2.0.

This project contains code ported from third-party libraries under their original licenses:

Library	License	Copyright
flexmark-java	BSD 2-Clause	2015-2016 Atlassian, 2016-2018 Vladimir Schneider
liqp	MIT	2010-2013 Bart Kiers
dart-sass	MIT	2016 Google Inc.
jekyll-minifier	MIT	2014-2024 DigitalSparky
terser	BSD 2-Clause	2012 Mihai Bazon
KaTeX	MIT	Khan Academy
Mermaid	MIT	Knut Sveidqvist
tree-sitter	MIT	2018 Max Brunsfeld
dagre/graphlib	MIT	Chris Pettitt
D3 curves	ISC	Mike Bostock

See LICENSE for full third-party notices.

AI-Assisted Development

The Java/JavaScript/Ruby/Dart-to-Scala 3 port was performed primarily using AI code generation tools (Anthropic Claude Code). All AI-generated code was reviewed, tested, and audited against the original sources by the project maintainer. Each ported file contains a header comment documenting its original source, migration notes, and audit date.