PEGO
A080: Generated Node Capture Scratch
Generated Node parsing creates temporary capture frames and slot arrays that need to live through parsing but not with the returned result. Separate reusable arenas reduce repeated scratch allocation.
Mechanism and Invariants
Frame and slot arenas are stable and append-only during a parse; individual
frames are never recycled at ordinary rule return. Recycle clears backing
storage, directory tails and undo/saved references. Reusable backing has a
combined bound of 1<<20 native words; unusually large scopes use exact
unretained allocations. Published Nodes remain in independent result slabs. The
limit bounds retained reusable scratch, not peak parsing memory.
Scope and State
Default generated Go Node parsing and capture-dependent recognition only. Typed AST captures, engine/VM execution and TypeScript retain their separate allocators.
Reference Control
None. The shared generated runtime always reuses the scratch; the former allocator is reproducible only from the revisions of record 092.
Evidence and Implementation
Record 092 measures capture-heavy Node parsing medians around 0.86–0.95 of its historical parent and lower allocation volume. An initial full XML sample is slower despite 15–17% fewer allocated bytes; later same-source rechecks favor scratch medians, with some ranges including parity. A field-layout control is inconclusive. These scoped observations support reusable scratch while retaining GC-sensitive uncertainty, rather than a general speed claim.
Evidence records: 092.
Source owners: node frame/slot scratch and parser release, capture scratch checks.
The comparison policy distinguishes same-source controls, historical changes and full checkpoints.