Sigil 0.23.0
A memory and runtime release. Native and C-to-WebAssembly programs use less memory, idle programs wake less often, and a full Unix socket queue no longer stalls other fibers.
Releases
Every Sigil release, with its full notes. Follow along with the Atom or RSS feed.
Sigil 0.22.17
Sigil now manages its own memory allocator. Native programs built for static Linux x86_64 and C-to-WASM web builds use mimalloc 3.5.3 behind a new allocator interface, and the sigil command itself switches with them. Long-running programs hold much less memory, and web builds start smaller and grow less.
Sigil 0.22.16
A bug-fix release for compilation, long-running programs and audio. The compiler keeps its intermediate values alive through garbage collection, completed child processes release their backing memory, and async producers and consumers resume correctly. Cues and streams also share output protection in the browser.
Sigil 0.22.15
A bug-fix release for closures and long-running programs. Capturing a conditional internal definition no longer breaks a closure, pipe readers keep moving on Linux static builds and Android, and short file reads no longer leave the garbage collector's allocation totals growing.
Sigil 0.22.14
A bug-fix release. syntax-rules now handles nested ellipses, sigil build --watch works again, and Sigil behaves better in scripts: no color codes in piped output, and clean version info.
Sigil 0.22.13
A bug-fix release. The headline: since 0.22.10, a non-ASCII character in any manifest string (an em-dash in a description:, say) broke sigil deps for every project that read it. That's fixed, along with a build hang, a few native string miscompiles and --dry-run.
Sigil 0.22.12
A correctness release. Sigil ignored a program's own binding of a builtin's name, such as a local not or an internal (define (car x) ...), on every backend, and several older bugs mixed up local names with macro keywords. Both are fixed. Release configs also compile optimized C by default now.
Sigil 0.22.11
A release in two parts. sigil task gives a project and its dependencies one way to share scripts, such as a game engine's publish tools. And a long list of memory-safety and correctness fixes, found by reading and testing the runtime closely: several were silent wrong answers or memory corruption that had been there for a long time.
Sigil 0.22.10
A correctness and build-cache release. Optimized builds could compute wrong answers in two patterns, compiled code skipped argument-count checks, and Sigil's caches could run the wrong compiled code, ship stale native code, or throw away work they had already done. All of that is fixed, and an unchanged rebuild of a program now recompiles almost nothing.
Sigil 0.22.9
A size release. Web builds of native-compiled apps are about 70% smaller, and call-heavy native code runs faster, because the compiler no longer spends most of each function's code on bookkeeping. Measured on Crash The Stack, Harkfell and Phantom Burn at the same commits.
Sigil 0.22.8
A correctness release. Release and web builds could drop the guard of a small helper procedure, comparisons with NaN answered true, and sigil mcp serve showed no tools in new Claude Code sessions. It also fixes a web app that doesn't import (sigil core), a from-path dependency that was silently left out, macros that allocated on every use in native code, and modules reused after SIGIL_FEATURES changed. More of R7RS now works without an import.
Sigil 0.22.7
A game audio and correctness release. Sound effects in the browser now play the moment they're triggered, a game's synth can drop to a lower rate on a weak phone, and sigil is ready to take upgrades from the signed registry. Three defects are fixed along the way: an error lost between nested guards, a -L path that stopped sigil starting, and tests run against dependencies the lock doesn't name.
Sigil 0.22.6
A reliability release for scripts, plus the groundwork for sigil env. Two defects let a program lose data or an error and still exit 0, and the command line swallowed -L arguments meant for other programs. All three are fixed, and several errors that named nothing now say what went wrong.
Sigil 0.22.5
A regular expressions and web reliability release, plus Windows icons. Sigil now has regular expressions in the standard library. Web builds could also fail in ways nothing on the code path explained: a type error from nowhere, or text that parsed fine natively coming back as garbage. Crash The Stack hit both, including a menu that froze on phones.
Sigil 0.22.4
A web audio release. A page that is not cross-origin isolated no longer mixes its sound on the main thread, so a long game frame no longer pops the audio. Found by Crash The Stack's live soundtrack on a phone over a plain http host.
Sigil 0.22.3
A native-codegen correctness release. Two defects found by Crash The Stack in its first week of play, both invisible to the bytecode VM and to every in-process test suite: a release binary that could crash at startup depending on where it was built, and a web build that leaked memory on every frame.
Sigil 0.22.2
A patch for the seams a game project hit in its first two days: between the two backends, between a game and the web loader, between what a docstring says and what a procedure does. It also repairs a 0.22.1 regression that stopped script-style source files from building. Everything here came from Crash The Stack's toolchain notes, each item with the measurement that found it.
Sigil 0.22.1
A cache-correctness and test-reliability release. The package cache now proves what it reuses: it hashes the bytes of every input and output it depends on, binds the compiler's own identity into the cache key, and declines to reuse anything it cannot fully account for. The test runner stops counting other checkouts' tests as your own, and its file summary can finally report a shortfall. An opt-in evidence journal records what a test run actually loaded and executed, for qualifying a release rather than trusting a green suite.
Sigil 0.22.0
A scripting and reliability release. Sigil is more convenient for operational scripts, the bundled client supports TLS 1.3, and builds and sockets recover more reliably from cache and resource problems. Direct file execution now provides the scripting prelude automatically; ordinary evaluation remains available through sigil eval -f.
Sigil 0.21.0
A test-reporting honesty release, and the first one that can turn a previously green suite red. sigil test could report success while running fewer tests than it appeared to, or none at all, and nothing in its output said so. Both cases now fail the run.
Sigil 0.20.3
A build performance and async-correctness release. Sigil recognizes when a package has not changed and skips it outright instead of walking its inputs again, which turns a no-change rebuild from a coffee break into a pause. Under the async scheduler, tcp-connect no longer stalls every other fiber while it waits. Applications built with Sigil also report their own version and commit separately from the runtime they were built against.
Sigil 0.20.2
An Android toolchain and native-build performance release. Sigil can now build dynamic Android/bionic AArch64 executables with managed Zig and a pinned, data-only Android sysroot, without requiring a separately installed full NDK. Full native release builds also stop compiling their Scheme dependency modules a second time during final bundling.
Sigil 0.20.1
A sandbox and native-codegen correctness release. Builds no longer hang when a sandboxed environment exposes Sigil's shared store as readable but not writable, and a caught exception raised by eval-string no longer abandons the rest of a native WASM caller. Process spawning can also give a child its own working directory and environment overrides.
Sigil 0.20.0
A dependency-declaration release, with one runtime fix that matters if you build to WASM. The sigil: field in package.sgl is now a minimum version rather than a range, so sigil: "0.16" means "needs at least Sigil 0.16" and stops expiring on its own.
Sigil 0.19.4
A build-integrity release. sigil build now checks, before it compiles anything, that your compiler and the runtime you have locked and installed are the same generation. -L also works for the first time on the modules the CLI loads at startup.
Sigil 0.19.3
An environment release. sigil env shell now hands your program the search paths its dependencies declare, not just the ones its top-level packages declare, so a tool finds the terminfo database and the helper binaries it was built against instead of quietly falling back to whatever the host happens to have.
Sigil 0.19.2
A correctness and speed release. Calling a native procedure with the wrong number of arguments now raises an arity error instead of reading whatever happened to be on the stack, native builds work on OpenBSD, and a native build refuses to link against a runtime older than the compiler that produced it rather than producing a binary that misbehaves later. Sigil also starts about three times faster.
Sigil 0.19.1
A compiler correctness release. Three optimizer defects could make a guard test a different value than the one you wrote, so a program takes the wrong branch with no crash and no failing test. One has shipped since 0.14.6. All three need optimize: 1 or higher, which means no test suite could catch them: sigil test, sigil eval and every dev build run at optimize: 0, where the code is correct. Rebuild and relock anything built at optimize: 1 or above.
Sigil 0.19.0
Sigil's core packages move back into the main repository. The toolchain was extracted into a dozen standalone repos a few months ago, each with its own version line, and every project carried a pin for each one. Now the core packages ship from one place on one version, and a project depends on Sigil rather than on a list of its parts. The language is unchanged; what changed is how you say which Sigil you want.
Sigil 0.18.6
A compiler correctness release. Optimized builds could silently take the wrong branch inside a loop: no crash, no error message, just a wrong answer from a program with no failing test. Three releases carry it, so anything built by 0.18.3, 0.18.4 or 0.18.5 at optimize: 1 or higher should be rebuilt on this release, and relocked as well, since sigil-stdlib is itself compiled by the compiler and a stdlib pinned inside the exposed window keeps carrying miscompiled code after the toolchain is upgraded. Alongside it, define with keyword parameters works in the REPL, eval stops leaking on every call, and a caller can choose the source address of an outbound connection. Two shapes that used to be accepted are now errors, both cases where the old behaviour silently did nothing.
Sigil 0.18.5
Most of this release is about Sigil telling you the truth when something goes wrong. Four of the six changes fix diagnostics that pointed somewhere other than the fault, and two of those could stop your process outright rather than reporting an error at all.
Sigil 0.18.4
Sigil source files can now select an installed language reader with #lang. A reader turns its source into ordinary located Sigil syntax, so a language can introduce its own notation while retaining Sigil's compiler, build graph, cache, runtime, and tooling. The same source works through compilation, direct execution, load, tests, bundles, native builds, and both WebAssembly backends.
Sigil 0.18.3
A toolchain correctness release. Sigil now resolves its runtime packages coherently, builds test suites without manufacturing dependency cycles, runs every discovered test file exactly once and reports a verdict for each one, and recompiles edits even when they land within the same second. Native builds also improve substantially: cross-module optimization summaries are active and bound to the exact compiler and bytecode they describe, native WebAssembly output is smaller and self-contained, and projects can grow past the old 256-module ceiling.
Sigil 0.18.2
A runtime correctness release, plus a headline feature: Sigil now has first-class shell scripting support via (sigil shell). On the correctness side, four distinct defects in exception dispatch are fixed, the most serious Sigil has shipped: a raise could remove the wrong handler, corrupt a live stack frame, or end the process with exit code 0 while work was still pending. Nine subcommand paths that used to die silently now fail loudly, and scoped package ids resolve local paths correctly. Anything long-lived built on 0.17.x (a server, an MCP tool, a CI controller) should be rebuilt on this release; consumers on a 0.18 caret range pick it up on relock.
Sigil 0.18.1
Every way into the Sigil CLI now reports failure honestly. Before this release a mistyped command, a script that raised, and a refused operation could all finish with exit status 0 and print nothing, which meant a CI step could report success for work it never did. Existing projects build without changes.
Sigil 0.18.0
The release that gives Sigil a verifiable supply chain. sigil env builds a project's whole toolchain from a lockfile, fetches prebuilt outputs from a signed registry instead of compiling them, and refuses anything whose bytes don't match what was signed. Alongside it, two build-integrity fixes you can see from the outside: builds that failed while reporting success now exit non-zero, and the same source built twice now produces the same binary. This is a minor bump because (sigil env) changed meaning. It's the environment engine now, and the old dotenv helpers moved to (sigil dotenv). Projects importing (sigil env) for dotenv need that one-line change; everything else builds without modification.
Sigil 0.17.20
A release that hardens the Sigil build. Three build-integrity improvements make a build's output verifiable: compiling the same source in two different directories now produces byte-identical bytecode, the build cache keys its entries by a canonical encoding so it can never hand back the wrong bytes, and the build store re-verifies every artifact it serves. Existing projects build without changes; the build cache rebuilds once on upgrade, since the bytecode and cache-key formats changed.
Sigil 0.17.19
A responsiveness release with two new capabilities. The headline is a scheduler fix that removes a roughly 100 millisecond stall from interactive apps: typing into a terminal or shell session that Sigil drives, and the output coming back, are now near-instant instead of laggy. Alongside it: pipe-based process primitives for driving a subprocess over ordinary pipes, and a WebAssembly binary lane that lets a wasm app return raw bytes to its host without encoding them to a string. Bytecode projects build without changes; native builds should be rebuilt from clean, since the native module ABI changed.
Sigil 0.17.18
A Slate preparation release. sigil app install can now install and launch a Sigil GUI desktop application, interface built in, so a graphical app like Slate installs with one command and runs from your application menu or your shell like any other program. Two runtime fixes land alongside it that matter for any long-running Sigil app: a memory leak that slowly grew until the app froze is cured, and idle CPU use drops sharply. Native builds are more trustworthy too: a compile that would once have silently shipped a broken artifact now fails loudly, and a changed source is never silently ignored. A correctness fix also lands for bitwise operations on large integers, which could silently return wrong values. Bytecode projects build without changes; native builds should be rebuilt from clean after upgrading, since the native module ABI changed.
Sigil 0.17.17
A native-codegen continuations release. Delimited continuations, coroutines, and generators now work correctly under the native backend compiled to WebAssembly, closing the last place they didn't. A companion fix stops long-running coroutine and async workloads from exhausting the fiber table, macro errors got much more specific, and there's a new experimental opt-in for compiling the standard library to native code. Existing projects build without changes.
Sigil 0.17.16
A browser runtime release. Two additive changes to the WASM DOM bridge and the web runtime let downstream web applications reconcile the DOM in place and register native modules of their own, with no change for existing projects. Both are plumbing consumed by the sigil-web-client and sigil-vt packages in their own releases.
Sigil 0.17.15
A string and character performance release. Text operations that used to crawl over long buffers are now native and linear: indexing an ASCII string is roughly 230 times faster, scanning mixed text has a new native cursor, and the bulk string, vector, and bytevector operations are single-pass native code. It also picks up shebang support for executable scripts and two runtime fixes from earlier in the series. Existing projects build without changes.
Sigil 0.17.14
A runtime and FFI release. The async scheduler stops oversleeping ready tasks, so timers and event loops stay responsive under load. The dynamic FFI gains native pseudo-terminals and wider callbacks, so Sigil can drive a real shell and take native signals with any number of arguments. And a fiber-corruption bug in native callbacks is fixed. Existing projects build without changes.
Sigil 0.17.13
A short follow-up to 0.17.12. sigil app install installs again, now building the app as a native binary the way a release build does, and the browser WebSocket layer can tell a still-connecting socket from a closed one. Under the hood the async runtime is more robust under concurrency: a busy goroutine no longer starves I/O, and channel wakeups no longer deadlock a long-running program. Existing projects build without changes.
Sigil 0.17.12
A records-and-methods release, with a native-async correctness fix that was silently breaking MCP servers. Two new core libraries, (sigil record) and (sigil method), bring extensible typed records and cached multimethod dispatch to the standard library, and a compiler fix lets procedural macros export across module boundaries at last. Alongside them, browser programs can now route DOM events straight into Sigil, a native-backend regression that dropped an async server's response mid-request is fixed, and two toolchain footguns are gone. Existing projects build without changes.
Sigil 0.17.11
The graphics-and-audio-on-the-web release. A Sigil program that draws with (sigil graphics) and plays sound through (sigil audio sink) now compiles to native WebAssembly and runs in a browser, with no Emscripten anywhere in the toolchain and no compile-C-directly workarounds in the build. This is the foundation the Cinder Cadence web port stands on: the full music-reactive game, native-compiled to a single WebAssembly module, rendering and playing in the browser. Two native-backend correctness fixes round out the release. Existing projects build without changes.
Sigil 0.17.10
A live-redefinition and interactive-correctness release. Native-compiled programs can now pick up redefinitions while they run, your editor can attach to an already-running program and evaluate straight into its modules, and a cluster of macro, module-resolution, and exception-cleanup bugs that surfaced during live-coding are fixed. Existing projects keep building without changes.
Sigil 0.17.9
A build-reproducibility and live-evaluation-foundations release. sigil build now produces byte-identical bundles from the same source and toolchain, two new runtime primitives lay the groundwork for interactive and streaming evaluation, and WebAssembly applications can now play audio through the browser. Existing projects keep building without changes.
Sigil 0.17.8
A WebAssembly and build-reliability release. Existing projects keep building without changes, with one action item for custom loaders (below).
Sigil 0.17.7
A native-codegen correctness release. Native compilation now resolves module bindings the way the bytecode interpreter always has: a re-export through a cond-expand import, and a nested eval that begins while another eval is still on the stack, both used to fail only under native compilation and now work. Native WebAssembly builds export the full eval ABI again, and a build bug that could silently link stale object files into a mixed-ABI binary after a header change is fixed. Existing projects keep building without changes.
Sigil 0.17.6
A correctness release. The headline is that the default way to build an application works again: sigil build produced a broken binary for the whole 0.17 series, and that is fixed. Alongside it, the exception-cleanup work started in 0.17.5 is now complete, so dynamic-wind and logging behave correctly even when an exception unwinds through a goroutine boundary; garbage collection gains frame-scheduling and server-heap controls plus a soundness fix in its incremental step; and an internal define-syntax that captures an enclosing binding now works. Existing projects keep building without changes.
Sigil 0.17.5
A bug-fix release centered on exception handling. On native and release builds, an uncaught exception could silently evaluate to #<undefined> and let execution continue instead of stopping; that is fixed, and dynamic-wind cleanup now runs correctly when an exception unwinds through it. Alongside that, the sigil mcp developer-tools server works again after being broken since an earlier refactor, and (gc-stats) gains real pause and memory observability. Existing projects keep building without changes.
Sigil 0.17.4
A bug-fix release. The headline is a startup crash: native WebAssembly builds broke in 0.17.3, and this release restores them. Alongside that, several failures that used to vanish silently now surface properly: a failed sigil eval, a process that cannot be started, and an unbound variable in native code all raise instead of slipping past. A reader crash on deeply nested input is fixed, and the build cache now notices when the compiler itself changes. Existing projects keep building without changes, though the first build after upgrading recompiles from scratch (see the last note).
Sigil 0.17.3
An additive release. The headline is that the threading macros move back into the core language, so ->, some->, and chain are available everywhere with no import. Alongside that: async web apps compiled to bytecode now suspend correctly in the browser, the auto-compile cache stops handing back stale modules, and a few build and CLI edges are cleaned up. Existing projects keep building without changes.
Sigil 0.17.2
Another additive release: a major new capability for the native WebAssembly target, plus two correctness fixes for async programs and the macro system. Existing projects keep building without changes.
Sigil 0.17.1
A small, additive release that makes long-running Sigil programs more robust: the kind that supervise child processes, and the kind that dial network peers. Two new standard library capabilities and one REPL fix. Existing projects keep building without changes.
Sigil 0.17.0
0.17.0 is the browser release: you can now build and ship real web apps in Sigil! The whole browser stack is new and labeled experimental, but it is no longer a demo. It has been validated by building real applications on it: a browser game and a PWA chat client, both running on the new bridges with zero app-author JavaScript. This release also makes async networking more resilient, hardens the register VM and the reader, and cleans up a few standard library and build edges. Existing native projects keep building without changes.
Sigil 0.16.0
0.16.0 is about making native Sigil applications feel faster in real use. The release focuses on runtime pacing, native-code generation, and the package versions used by the CLI, rather than changing the surface language.
Sigil 0.15.0
0.15.0 reverses the 0.14 core toolchain extraction. Splitting the compiler, runtime, standard library, build system, dependency resolver, and test runner into separate release streams made the version story harder than it needed to be. It became too easy to ask "what version of Sigil is this?" and get a different answer from each part of the toolchain.
Sigil 0.14.0
The compiler, runtime, build system, and standard libraries have been split into their own repositories. codeberg:sigil/sigil is the user-facing CLI; codeberg:sigil/sigil-lang is the compiler and runtime; codeberg:sigil/sigil-build is the build system; and twenty-plus standalone library repos make up the rest of the ecosystem. To match this, packages declare a single sigil: field that the build system uses to specify which version range of Sigil they are compatible with. Most package manifests get smaller as a result.
Sigil 0.13.0
Sigil ships as a native binary. The release CLI is compiled end-to-end through the native C backend — no bytecode, no interpreter loop, no runtime-compile on startup. Every sigil invocation on 0.13.0 exercises the native runtime. This release also introduces a full Language Server Protocol implementation (sigil lsp serve), restructures the native compile pipeline for visibility and parallelism, and lands the cell-elision and escape-analysis codegen optimizations default-on.
Sigil 0.12.0
Register VM stabilized, stack VM removed, and experimental native C codegen. This release makes the register-based virtual machine the sole execution backend — the legacy stack VM and direct compiler have been removed. The register VM is now battle-tested across production MCP servers (folio, courier, bureau) and the full Sigil ecosystem. This release also introduces an experimental C native code generation backend.
Sigil 0.11.0
Register VM and self-hosting CPS compiler. This release adds a register-based virtual machine as an alternative backend for the CPS compiler introduced in 0.10.0. The new toolchain is opt-in via SIGIL_NEXT=1 and is 7-57% faster than the direct compiler across all benchmark categories. It is fully self-hosting — the CPS compiler running on the register VM can compile itself.
Sigil 0.10.0
Experimental CPS compiler with optimization passes. This release adds a continuation-passing style intermediate representation to the compiler pipeline, sitting between macro expansion and bytecode generation. The CPS path is opt-in and does not change default compiler behavior.
Sigil 0.9.1
Transitive dependency resolution, version ranges, and lockfile support. The package manager now recursively resolves the full dependency tree — projects only need to declare their direct dependencies, and everything else is fetched automatically. This is the feature that makes the extracted ecosystem from 0.9.0 practical to use at scale.
Sigil 0.9.0
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.
Sigil 0.8.0
Dynamic FFI and portable foundations. Sigil gains the ability to call any C library at runtime without writing glue code, a content-addressable build cache for faster incremental builds, and seven new packages spanning graphics, game development, calendar sync, and messaging. Cross-compilation now passes across all eight platform targets, and a new app management system makes it easy to install and run Sigil applications from git repos. With this release, Sigil reaches a stability point that enables us to begin decoupling libraries from the monorepo for independent releases and faster iteration.
Sigil 0.7.0
Parallelism and production readiness. Sigil gains multi-core execution, better I/O scalability, proper exception semantics, machine-readable procedure specifications, structured logging, and four new packages. With the stability and DX foundations from 0.5.0 and 0.6.0, this release focuses on the features needed to build and run serious applications.
Sigil 0.6.0
This release brings Sigil much closer to full R7RS compliance, adds a complete web development workflow with live browser reloading, and introduces three new packages: a PEG parsing library, an Org Mode parser, and an XMPP client. Developer tooling improves significantly with rich error diagnostics, an enhanced MCP server, and watch mode for incremental builds.
Sigil 0.5.0
This release is all about stability and correctness. A comprehensive audit of the garbage collector uncovered and fixed a critical write barrier gap, and GC stress testing now runs across the entire compiler pipeline. The HAMT dict implementation is complete, arbitrary-precision integers (bignums) are fully integrated, and every open issue has been resolved. Performance improves with inline caching and superinstructions, and the multimedia packages have been reorganized for flexibility.
Sigil 0.4.0
This release makes Sigil leaner and faster. Native list operations cut compilation time in half, release binaries are 44% smaller, and a new profiling module helps you find bottlenecks in your own code. Macro authors get full hygiene support, and error handling improves with catchable VM errors and cleaner stack traces.
Sigil 0.3.0
This release focuses on modular compilation and improved application bundling. Native dependencies like SQLite, TLS, and crypto are now separate packages, so applications only compile what they actually use. The new sigil publish command provides a complete static site generation pipeline, and bundling gains script mode support for simpler deployments.
Sigil 0.2.0
This release focuses on improving the idiomatic functional programming style of Sigil. New modules for sequences and function composition make it easier to write clean, composable code. Pattern matching gains dict, vector, and struct support, and several APIs have been refined for consistency.
Sigil 0.1.0
The first public release of Sigil, a practical Scheme for building standalone applications.