cure-tree 0.4.4

Generic arena-tree toolkit for cure language frontends: inline ChildList, name interning + node keys, region-event index (lazy rebuild), effect table rebuild
Documentation

cure-tree

crates.io Documentation License: MIT

Generic arena-tree toolkit for cure language frontends: the infrastructure every language AST would otherwise reimplement. A new language frontend = this kit + its own NodeData / parser / printer / rule pack.

What's in the kit

Component What it does
[ChildList<Id>] children container with ≤3-child inline storage (zero heap allocation for the vast majority of AST nodes; spills to heap for Block/Call fan-outs)
[NameTable] unit-level name ↔ u32 interning (append-only) + per-node name-key table with incremental extension — makes Lang::NameKey comparisons integer equality
[EventStore<Id, NameKey>] region-event index storage with B3 lazy rebuild: edits invalidate only affected statement slots, prepare rebuilds only empty slots
[collect_region_events] generic event collector — dispatches purely on Lang hooks (is_opaque / var_key / kind / children / un_op), strictly matching the engine's scan_region recursion order
[stmt_roots] statement-root enumeration (direct children of Blocks)
[rebuild_effects] per-node aggregate effect table rebuild (fixed-point sweep for injected nodes whose index exceeds their parent's)

Conventions

The kit assumes (and documents in the crate docs):

  • Dense arena: Lang::node_index and Lang::id_of_index are mutual inverses; Id: Copy.
  • u32 interned name keys: your Lang::NameKey is a u32 intern id from NameTable — region scans degenerate to integer comparisons.
  • Children layouts follow the [cure_engine::kind::NodeKind] contract (e.g. Assign = [target, value]) — the collector traverses accordingly.

Proof it works: the reference consumer + a toy language

  • cure-java-ast is built on this kit (the Java reference implementation). After the extraction, the 371,674-file OpenJDK corpus produced byte-identical output.
  • tests/kit.rs builds a complete toy language in ~100 lines on top of the kit and verifies event semantics (Use/Write/Shadow/opaque), effect aggregation, invalidation, and lazy rebuild.

License

MIT. Zero dependencies beyond cure-engine.