Lyric

What changed in v2.0.0 — 2026-08-20

The specification is normative from this release on: lyriclang/lyric-spec defines the language, the toolchain implements it, and a divergence is a toolchain bug. The major cuts the SOURCE surface — everything the 1.x deprecation clocks announced — while the bytecode format stays 3.2 and bytecode compiled against 1.x keeps loading.

Removed — the 2.0 cut

Everything @Deprecated announced through 1.x is gone from the source surface. The registry still binds the old NATIVE names, so bytecode compiled against 1.x keeps loading; what the cut takes is the ability to write the old forms in new code.

• The free string forms (length(s), trim(s), toUpper(s), … — 27 declarations): the method API (s.length(), v1.15) is the one form. concat and repeat stay free — they back + and * — and the fromXxx/parseXxx families keep their names.
• The free constructors emptyList, emptyMap, emptySet, newStringBuilder: constructors live on the types (List<T>.empty(), StringBuilder.new(), v1.12).
• std.math.Random and newRandom: randomness lives in std.random (v1.14).
• write/writeln: print/println take any Display value (v1.14).
• StringBuilder.length(): it counted appended PIECES, an implementation detail; measure the built string. (It never carried @Deprecated — an attribute cannot sit on a member — its doc announced the 2.0 removal instead.)

Changed

• Hashable<T> declares Equatable<T> as its parent. A hash table cannot exist without equality; demanding the hash without the comparison was a lie by omission. A key constraint is K :: [Hashable<K>] alone — Map, Set and their helpers dropped the second constraint. A type conforming to Hashable now implements hash AND equals.
• LYR-SEM0074 is an error. Calling a static extension method through an instance was a warning through 1.x with the message announcing this change; the clock has run out. The one 1.x→2.0 severity change, recorded as such in the specification (§12.1).
• docs/Grammar.md and docs/Bytecode.md are checked mirrors. The canonical home of both is lyriclang/lyric-spec (chapters 02 and 13); CI diffs the copies here against the specification, so drift fails the build.
• A library prunes from its pub surface. A compile without an entry point takes the pub functions of the compiled modules as reachability roots — a library's surface decides its contents, and the standard library no longer ships whole inside every library or embedded script. Observable at the host boundary: a private function nothing public reaches is not in the module (Defines says so), which is why this waited for the major.

The full changelog →