PEGO
A010: Compact Node Representation
Every constructed Node carries names, positions, children and fields. Compact fields and shared kind metadata reduce per-node backing without changing the tree's observable names or JSON representation.
Mechanism and Invariants
Fields is an ordered slice of name/value pairs rather than a per-node map.
NodeKind interns the type/rule pair, and rules precompute their kinds so
matching does not perform an interning lookup. Node positions are int32;
callers retrieve names through Type() and Rule(). Field lookup and sorted
JSON output preserve their contracts. Slabs and snapshot records are separate
storage mechanisms.
Scope and State
Default Node layout in closure, both VMs and generated Go Node output. Typed Go results use their own structs; TypeScript uses JavaScript objects and does not share the Go layout.
Reference Control
No private same-source old-layout comparator is maintained. Comparing a historical Node layout changes public representation as well as size.
Evidence and Implementation
Record 003 reports JSON allocation volume from 72 to 64 MB after replacing maps. Record 063 measures 11–20% lower Go allocation volume, with timing within roughly 3%; record 064 records generated allocation reductions with mixed small timing effects. The recorded 88-byte Node size is host/layout-specific and does not imply an equal percentage reduction in total heap.
Evidence records: 003, 063, 064.
Source owners: Node and NodeKind,
generated Node and Fields.
The comparison policy distinguishes same-source controls, historical changes and full checkpoints.