0.6.1 - 2026-06-16

Release Notes

Fixed

• A relative meta.load-css inside a first-class mixin (captured with
  meta.get-mixin and invoked via meta.apply) now resolves against the
  mixin's defining file, not the caller's (issue #8). The regular
  namespaced include path was already correct.

Added

• A C ABI (ffi/, libsasso + sasso.h) — drive sasso in-process from any
  language with a C FFI, with a userland importer callback. Releases now attach a
  per-target sasso-<version>-<target>-c-api.{tar.xz,zip} (prebuilt static +
  dynamic library + header). See the "C ABI" section in the README.

Install sasso 0.6.1

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.6.1/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.6.1/sasso-installer.ps1 | iex"

Download sasso 0.6.1

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.6.0 - 2026-06-15

Release Notes

Changed (breaking)

• The Importer trait is now dart-sass's two-phase canonicalize/load
  (issue #4, RFC in docs/IMPORTER_REDESIGN.md). It replaces the old
  resolve(path) -> Option<String> plus the accreted resolve_* overloads:

  fn canonicalize(&self, url: &str, ctx: &CanonicalizeContext)
      -> Result<Option<CanonicalUrl>, ImporterError>;
  fn load(&self, canonical: &CanonicalUrl)
      -> Result<Option<ImporterResult>, ImporterError>;

  canonicalize resolves a URL to a stable identity without loading (its result
  is the module-cache key); load fetches the source as an
  ImporterResult { contents, syntax, source_map_url }. Three outcomes:
  Ok(Some) = handled, Ok(None) = not handled, Err(ImporterError) =
  handled-but-failed (an actionable compile error rather than a silent miss).
  New public types: CanonicalUrl, ImporterResult, ImporterError,
  CanonicalizeContext. A clean break with no compatibility shim (pre-1.0).
  FsImporter and the built-in resolution are unchanged in behavior (sass-spec
  ratchet delta +0); only custom Importer implementations must migrate.

Added

• ImporterResult.source_map_url lets an importer set the URL recorded for a
  loaded file in generated source maps (dart-sass ImporterResult.sourceMapUrl).

Install sasso 0.6.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.6.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.6.0/sasso-installer.ps1 | iex"

Download sasso 0.6.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.5.3 - 2026-06-15

Release Notes

Fixed

• !default no longer evaluates its right-hand side when the variable is
  already set. dart-sass short-circuits a guarded (!default) assignment
  before evaluating the RHS, so an expression that would otherwise error is
  harmless once the variable already holds a non-null value; sasso evaluated the
  RHS first. This surfaced in Bootstrap-on-Shopware setups where, after an
  override sets $w: 1rem, a later $p: $w + .5em !default raised an
  "incompatible units" error instead of being skipped. Thanks to
  @shyim (#2).
• Legacy rgb()/hsl() preserve the caller's rgba/hsla spelling in
  special-value and relative-color passthroughs. When a call can't resolve to
  a concrete color (a channel or alpha is a var()/env()/non-foldable
  calc()), dart-sass keeps the call and the exact function name written;
  sasso normalized rgba/hsla down to rgb/hsl, breaking Bootstrap's
  rgba(var(--bs-body-color-rgb), …) output. The called name is now threaded
  through every passthrough, keeping dart's carve-out that a none-only call
  still normalizes to the canonical rgb/hsl (and a calc() alpha that folds
  to a number resolves to a real color rather than a passthrough). Thanks to
  @shyim (#3).

Install sasso 0.5.3

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.5.3/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.5.3/sasso-installer.ps1 | iex"

Download sasso 0.5.3

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.5.2 - 2026-06-14

Release Notes

Fixed

• Expanded @at-root group-separation blank lines. dart-sass writes one
  blank line at an @at-root hoist→resume boundary when the hoisted chunk ends
  in a style rule, while keeping a nested-@at-root chain and a rule + its own
  bubbled @media contiguous. sasso previously diverged BOTH ways — it never
  emitted the blank before a resumed parent rule, and it over-emitted (three
  blanks between top-level bare-@at-root siblings, spurious blanks between a
  nested-@at-root chain's rules / between a rule and its own bubbled @media /
  before an @at-root body's trailing comment). Now byte-exact vs dart-sass
  1.101 across a dedicated 54-shape group-separation sweep, with non-@at-root
  output byte-identical. Compressed output is unaffected (no blank lines).
  (sass-spec does not cover these @at-root-resume blanks.)

Install sasso 0.5.2

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.5.2/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.5.2/sasso-installer.ps1 | iex"

Download sasso 0.5.2

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.5.1 - 2026-06-14

Release Notes

Source-map fidelity + compressed-output corrections, all byte-exact vs
dart-sass 1.101.

Fixed

• Source maps: @media/@at-root/@supports bubbled parent selector. When
  one of these at-rules nested in a style rule bubbles a copy of the enclosing
  selector out (@media screen { .a { … } }), that copy now maps back to the
  ORIGINAL rule's source position, matching dart-sass. It previously had no
  mapping at all — which in compressed output also let the consecutive-same-
  source-line coalescing drop a following declaration's mapping (a 0.5.0
  regression vs 0.4.0 for @media/@at-root-bubbled rules). CSS is unchanged.
• Source maps: @supports header. The @supports (…) at-rule header now
  maps to its @supports keyword (as @media already did); previously it had
  no mapping. CSS is unchanged.
• Compressed @media/@supports whitespace. Compressed output now omits the
  space before a prelude beginning with ( for @media/@supports
  (@media(min-width: 1px)), and within a @media query drops the space before
  and/or after a ) ((a)and (b)) and after the comma between queries
  ((a),(b)) — matching dart-sass. Other at-rules (@container) and @supports
  conditions keep their spaces. (Compressed CSS output change; expanded
  unchanged.)

Install sasso 0.5.1

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.5.1/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.5.1/sasso-installer.ps1 | iex"

Download sasso 0.5.1

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.5.0 - 2026-06-14

Release Notes

Added

• wasm: source maps. The @momiji-rs/sasso package's compile(scss, { sourceMap: true [, sourceMapIncludeSources: true] }) now returns
  { css, sourceMap } (the v3 map as a parsed object) instead of a bare CSS
  string; without sourceMap it still returns the string (backwards
  compatible). New sasso_compile_map export returns a framed [u32 css_len][css] [map json] buffer. Source maps are now exposed on every surface (lib, CLI,
  wasm).

Fixed

• Compressed source maps now emit one segment per source line, matching
  dart-sass (compressed packs many tokens onto a line; dart maps only the first
  per source line). Expanded maps are unchanged. The map's CSS is unaffected.

Install sasso 0.5.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.5.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.5.0/sasso-installer.ps1 | iex"

Download sasso 0.5.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.4.0 - 2026-06-14

Release Notes

Added

• Source map (v3) support. New compile_with_source_map(source, &Options) -> CompileResult { css, source_map: SourceMap }, with SourceMap::to_json()
  and Options::with_source_map_include_sources(bool). The CLI gains
  -o/--output <file> (write CSS to a file), --source-map (also write a
  <output>.map sidecar + append the sourceMappingURL footer),
  --embed-sources, and --source-map-urls=relative|absolute. Output is
  byte-for-byte identical to dart-sass for the common cases (selector +
  declaration-name mappings; expanded + compressed). The plain compile path
  and stdout output are unchanged. (Deferred for now: declaration-value-start
  mappings, the inline --embed-source-map data URI.)

Changed

• Internal maintainability refactors only (no behaviour change, byte-identical
  output): the .sass line scanners, the is_builtin name table, and the
  oversized eval/selector/parser files were split into domain modules;
  the string serializers gained a no-escape fast path.

Install sasso 0.4.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.4.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.4.0/sasso-installer.ps1 | iex"

Download sasso 0.4.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.3.1 - 2026-06-13

Release Notes

Fixed

• Compressed output now emits a color's canonical CSS name when it is no longer
  than the shortest hex, matching dart-sass (red not #f00, aqua not
  #0ff; duplicate names resolve to dart's canonical pick — cyan/grey →
  aqua/gray). Expanded output (which preserves the authored spelling) is
  unchanged.

Install sasso 0.3.1

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.3.1/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.3.1/sasso-installer.ps1 | iex"

Download sasso 0.3.1

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.3.0 - 2026-06-13

Release Notes

Since 0.2.0. Conformance holds at 100% of the attempted sass-spec suite
(13,896 / 13,896) — but that suite covers valid inputs plus the errors it
expects; this cycle hardened sasso to reject the same malformed inputs
dart-sass rejects, and cut more of the @extend and value hot paths.

Changed

• Strict input validation. Beyond matching dart-sass's output, sasso now
  errors — rather than silently accepting — on malformed input, each with
  dart-sass's exact message: an invalid hex literal (#00000, #0g),
  out-of-grammar rgb()/hsl() channel units and legacy-vs-modern argument
  shapes, a duplicate @mixin/@function parameter, a malformed number
  exponent (1e-), a non-identifier @use/@forward namespace, a misplaced
  @content/@extend, a style rule / declaration / @extend in a @function
  body, a map or empty list used as a CSS value (#{(a:1)}, -()), a
  malformed :nth-child() An+B or empty :not() selector, a stray ! in a
  selector, a leading-empty @extend target, and a malformed @charset /
  @at-root (…) query. Found by a leniency-mining sweep that diffed every
  category against dart-sass; the fixes are uncovered by the spec, so the
  ratchet is unchanged.

Performance

• Transitive @extend went from ~151× slower than dart-sass to faster
  on a deep extend chain: a match pre-filter with typed dedup, an incremental
  per-rule fold (killing the O(N²) closure re-derivation), borrowed
  scope-originals, and cached typed selector hashes — the @extend maps are
  now FxHash + typed Complex/Simple keys, guarded by a render-injectivity
  parity proof. Byte-identical output throughout.
• Reference-counted composite values — Str/List/Map are Rc-backed,
  so cloning a read-only $variable is an O(1) refcount bump instead of a deep
  copy (copy-on-write for the mutating builtins): ~7× fewer instructions and
  ~13× less peak memory when a large list/map is passed through a call chain.
• Cow-borrowed argument-name normalization (called 4–6× per function
  call) plus trimmed function-call-path allocations — ~15% fewer instructions
  on a function-heavy compile.
• Arena in-place realloc — the scoped bump arena extends its tail
  allocation in place instead of stranding a dead buffer on every Vec
  doubling, trimming peak memory on parse-heavy compiles.
• Net: pure-compile throughput ~7.4 ms on the large benchmark (was ~9–10),
  ~2.3–2.9× faster than grass and ~19–30× faster than the dart-sass JS bin.

Internal

• eval.rs split into an eval/ module directory and color.rs into a
  color/ directory (pure code moves); the typed selector model gained a
  parity-proof harness; the stringly hoist markers became typed OutNode
  variants; the @extend cartesian-order bool became a CartesianOrder enum;
  OutNode rule/at-rule constructors collapsed duplicated construction sites.
  All byte-identical, each verified base-binary-vs-refactor.

Tooling

• The WebAssembly npm package publishes via OIDC Trusted Publishing (no token).
• Benchmark harness uses portable temp-file handling (mktemp -d).

Install sasso 0.3.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.3.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.3.0/sasso-installer.ps1 | iex"

Download sasso 0.3.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum

0.2.0 - 2026-06-11

Release Notes

Everything since the initial 0.1.0 crates.io publish. This grew the compiler
from an early vertical slice to 100% of the attempted official sass-spec
suite (13,896 / 13,896, zero failures — 11,405 byte-exact CSS outputs plus
2,491 error specs correctly rejected; the 8 remaining cases are tagged :todo
for dart-sass itself upstream), matching current dart-sass (1.100) byte-for-byte.
The pass is measured against a conformance harness tightened to reproduce the
official sass-spec comparator (normalizeOutput) exactly — collapse newline
runs only, no extra whitespace leniency — so the count holds under the upstream
comparator, not just a looser local one.

Added

• Byte-exact diagnostics — errors, @error, @warn, and @debug now
  reproduce dart-sass's stderr byte-for-byte: source-span ╷│╵ snippets with
  carets and right-aligned gutters (tab→4 spaces), aligned stack frames
  (root stylesheet / name() / @import), a --no-unicode flag, and the
  @import deprecation warning (with a per-id cap/dedup deprecation registry).
  238 of the suite's 3,256 stderr expectations now match byte-for-byte (a
  spec/run_spec.py --check-stderr metric tracks it); the rest (other
  deprecations, multi-span layouts) build on this foundation.
• @use / @forward module system — built-in sass:* modules and user
  files, with configuration, namespacing, @forward prefix/show/hide,
  dash-insensitive member access, forward conflict resolution, and star
  (as *) modules.
• Indented .sass syntax — a full front-end (Options::with_syntax, the
  CLI --indented flag, .sass extension inference), including cross-syntax
  @import of partials by file extension.
• CSS Color 4 color spaces — srgb/display-p3/lab/lch/oklab/
  oklch/xyz via color(), with modern color serialization.
• @extend and %placeholders — a faithful port of dart-sass's
  ExtensionStore engine: registration-order extension folding, selector
  weaving/unification/trimming, @use/@forward cross-module visibility, and
  the self-referential :not/:has pseudo cases — closing the suite's
  @extend family to byte-exact parity.
• Built-in function modules — meta (first-class function references via
  get-function/call, existence predicates), math (clamp/min/max/
  round/log and friends), list (bracket-preserving join/append),
  map (nested key paths, deep-merge/deep-remove), string
  (split/unique-id), and selector functions.
• First-class mixins — meta.get-mixin returns a mixin value and
  meta.apply invokes it (with @content support).
• CLI — compile multiple input files in one process (sasso a.scss b.scss,
  startup shared across files); --loop <N> for in-process throughput and
  -q/--quiet to suppress stdout (used by the benchmark harness).
• Benchmark harness — sasso registered as a first-class engine in bench/;
  three-way report bench/three_way.md (sasso vs
  dart-sass vs grass).
• CODE_OF_CONDUCT.md adopting the
  Sass Community Guidelines, as
  the Sass project asks every implementation to do.
• This CHANGELOG.

Changed

• Selector resolution now matches dart-sass on combinator normalization,
  adjacent-compound separation, and bogus-combinator omission.
• color functions match dart-sass strictness: channel-unit leniency in
  adjust/change, missing/powerless-channel errors, the Microsoft alpha()
  filter overload, and adjust-hue rejecting non-legacy colors.
• selector functions coerce string/list arguments and validate arity, and
  accept a list of extendees in extend/replace.
• list builtins validate fixed-arity arguments and preserve list shape.
• Unquoted string serialization collapses newlines to spaces; custom-property
  values are emitted verbatim — both matching dart-sass.
• Control-flow blocks use semi-global scoping with a global-write guard.

Performance

Profiling showed the compiler is allocation- and hashing-bound; a series of
hot-path cuts followed, with no behavior change (cumulative ~2× faster on the
large benchmark vs. the original, lifting the lead over grass to ~1.9–2.4× and
over dart-sass to ~16–25×):

• Selector helpers split_commas/tokenize_complex return borrowed &str
  slices, and copy_name/normalize_selector avoid their intermediate
  String/Vec — no per-part/per-token/per-name heap allocation on the hot
  selector-resolution path.
• The compiler's internal String-keyed maps (variable scope, function/mixin
  tables, module maps) use a small inline FxHash hasher instead of std's
  DoS-resistant-but-slow SipHash. (Still zero runtime dependencies.)
• A scoped bump-arena allocator (ScopedAlloc): within each compile() a
  per-thread arena turns every allocation into a pointer bump and frees them
  wholesale (reset) at the end — a further ~1.5×. It is installed as the CLI's
  #[global_allocator]; library/wasm embedders can opt in the same way (it
  forwards to the system allocator outside a compile, so it's safe to install
  unconditionally). This is the library's one audited unsafe module —
  verified by unit tests, Miri (no UB), AddressSanitizer, and the full sass-spec
  suite run through it (zero crashes, byte-identical output); the
  rest of the crate is deny(unsafe_code). Still zero runtime dependencies.
• Smaller Value — the Color variant's modern-color payload is boxed, so
  the Value enum drops from 128 to 64 bytes (a compile-time size_of
  guard prevents regressions). Halves every scope-map slot, Vec<Value> element
  and lookup clone, with byte-identical output.
• Zero-dependency Ryū float formatter — a from-scratch d2s shortest-round-
  trip formatter on the float-to-string hot path, replacing core::fmt, with a
  differential fuzz test against a reference.

Tooling

• The conformance ratchet pins the sass-spec commit (spec/SPEC_VERSION.txt)
  for reproducibility, with a --latest/--canary drift-detection mode.
• The conformance harness now reproduces the official sass-spec comparator
  (sass-spec/lib/test-case/compare.ts normalizeOutput) exactly, so a "pass"
  means byte-identical under the upstream comparator — no extra local leniency.

Install sasso 0.2.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/momiji-rs/sasso/releases/download/v0.2.0/sasso-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/momiji-rs/sasso/releases/download/v0.2.0/sasso-installer.ps1 | iex"

Download sasso 0.2.0

File	Platform	Checksum
sasso-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
sasso-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
sasso-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
sasso-aarch64-unknown-linux-gnu.tar.xz	ARM64 Linux	checksum
sasso-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum
sasso-aarch64-unknown-linux-musl.tar.xz	ARM64 MUSL Linux	checksum
sasso-x86_64-unknown-linux-musl.tar.xz	x64 MUSL Linux	checksum