Lyric

What changed in v4.4.0 — 2026-09-04

Pattern matching becomes complete. Two forms the grammar always admitted, the checker always accepted, and the lowering never built. Both are additive: every program that compiled before compiles unchanged, and the bytecode format is untouched.

Added

• A match takes a struct or a class apart.

  struct Point { x: int, y: int }
  
  fn sum(p: Point): int {
      return match (p) {
          Point { x, y } => x + y,
      };
  }
  

  It tests nothing — the value is already of that type — so one arm covers the whole match. Point { x = across } binds under a name of your own, _ in a field's place skips the field, and a field left out is not read at all. A bound field is a copy, exactly as let x = p.x; is.

  A field pattern only binds: writing a test into one (Point { x = 3 }) is refused, and the refusal names the field it sits on.

• A match over an optional enum takes both states.

  fn area(s: ?Shape): int {
      return match (s) {
          null                => -1,
          Shape.Dot           => 0,
          Shape.Rect { w, h } => w * h,
      };
  }
  

  Presence is settled before any variant is examined, because the tag lives inside the optional — and that changes nothing about which arm answers: the arms are tried in the order they were written, wherever the null arm stands among them.

  Before this, both forms failed at compile time with LYR-IR0001. Nothing that worked has changed.

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