Sigil 0.9.0

March 31, 2026release

Lean core, ecosystem split, Zig everywhere. Sigil's monorepo sheds over 25,000 lines as libraries move to independent repositories with their own release cycles. The standard library is streamlined for AI-native development — pattern matching, transducers, R7RS compatibility, and functional programming utilities move to optional packages. Zig replaces GCC as the default C compiler for native builds, and Emscripten is replaced entirely by Zig + WASI for WebAssembly, enabling the Sigil REPL to run in browsers without heavyweight toolchain dependencies.

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Ecosystem Split

The monorepo shrinks from 39 packages to 26. Extracted libraries are now independent repositories on Codeberg under the sigil/ organization, each with their own version tags, CI, and release cycle.

Extracted Package	Repository	Description
sigil-peg	codeberg.org/sigil/sigil-peg	PEG parser combinators
sigil-sxml	codeberg.org/sigil/sigil-sxml	SXML to HTML/XML conversion
sigil-markdown	codeberg.org/sigil/sigil-markdown	CommonMark parser with YAML front matter
sigil-web	codeberg.org/sigil/sigil-web	Web application framework
sigil-css	codeberg.org/sigil/sigil-css	Programmatic CSS generation
sigil-match	codeberg.org/sigil/sigil-match	Pattern matching
sigil-fp	codeberg.org/sigil/sigil-fp	Functional programming utilities (compose, pipe, partial, threading macros)
sigil-transducers	codeberg.org/sigil/sigil-transducers	Composable transducers
sigil-r7rs	codeberg.org/sigil/sigil-r7rs	R7RS-small compatibility (scheme *) modules and SRFI-9 records
sigil-web-repl	codeberg.org/sigil/sigil-web-repl	Browser-based REPL (was sigil-playground)
press	codeberg.org/sigil/press	Static site generator (was sigil-publish)
sigil-site	codeberg.org/sigil/sigil-site	Official Sigil website
sigil-web-demo	codeberg.org/sigil/sigil-web-demo	Demo web application

Extracted packages use from-git dependencies and dev-redirects.sgl for local development. All existing functionality is preserved — packages just live in their own repos.

AI-Native Standard Library

The standard library is streamlined based on a comprehensive audit of how AI agents actually use Sigil across 12 production codebases (117 libraries). Features with zero AI usage were moved to optional packages:

Pattern matching (match, match-let) — moved to sigil-match
Transducers (mapping, filtering, transduce) — moved to sigil-transducers
Functional combinators (compose, pipe, curry, partial, cut/cute) — moved to sigil-fp
Threading macros (chain, ->, some->) — moved to sigil-fp
R7RS compatibility ((scheme base), (scheme write), etc.) — moved to sigil-r7rs
SRFI-9 records (define-record-type) — moved to sigil-r7rs

The core language retains what AI agents naturally reach for: when/unless, keyword arguments, define-struct, guard/error, map/filter/apply/find, dicts, broadcast channels, and go concurrency.

Zig as Default Compiler

Zig is now the preferred C compiler across all build paths:

Native builds: detect-default-compiler and compile-native-tests prefer zig cc when available, falling back to system cc/gcc
Cross-compilation: All eight platform targets use Zig (unchanged from 0.8)
CI: Test and GC stress jobs use Zig via with-zig wrapper
WebAssembly: New web build config uses zig cc -target wasm32-wasi (see below)

WebAssembly Without Emscripten

The web build target is completely rewritten. Emscripten is replaced by Zig targeting wasm32-wasi with a browser WASI polyfill:

All 34 C source files compile with zig cc -target wasm32-wasi
3.3MB WASM binary (comparable to Emscripten output)
Uses @bjorn3/browser_wasi_shim for WASI polyfill in browsers
New __SIGIL_WASM__ platform define replaces __EMSCRIPTEN__ guards
Web build config: sigil build sigil-web-repl --config web
Sigil REPL runs fully in the browser — expression evaluation, module loading, interactive input

sigil-docs Trimmed

sigil-docs is now a lightweight JSON lookup package for REPL inline help:

Removed (sigil docs commands) — the sigil docs CLI subcommand. Press handles all doc site generation now.
Removed (sigil docs execute) — code block execution for doc validation
Removed dependencies on sigil-markdown and sigil-sxml
Remaining: (sigil docs lookup), (sigil docs search), (sigil docs types) — just reads the JSON files the compiler generates

sigil-cli Slimmed

The CLI drops several optional command modules and dependencies:

Removed sigil docs command (handled by press)
Removed sigil publish command (handled by press)
Removed sigil changes command (package deleted)
Removed dependencies: sigil-docs, sigil-web, sigil-changes