PEGO
A130: Closure Lambda Arenas
Calling list-processing lambdas need not allocate a new parameter list and evaluation context every time.
Mechanism and Invariants
Closure calls take parameters and contexts from LIFO arenas and release them at return. Lambda values use an evaluation-scoped arena. A lambda created inside a nested call keeps a heap copy of the enclosing context when required, preventing a popped arena window from becoming its environment. Function values cannot escape into grammar fields or variables.
Scope and State
Default closure-backend action/predicate evaluation only. VM lambda chunks and generated language closures are separate mechanisms.
Reference Control
No maintained same-source heap-per-call comparator exists.
Evidence and Implementation
Record 026 reports JSON closure allocations about 37k to 1.3k and CSV 56k to 0.8k, with smaller timing improvements. Lambda-free XML/Operators workloads are unchanged. Results apply to those historical closure workloads, not arbitrary escaping functions.
Evidence records: 026.
Source owners: closure.apply and evaluation arenas, evalCtx.keep.
The comparison policy distinguishes same-source controls, historical changes and full checkpoints.