layer-4-parser/README.md

Layer 4 — Incremental Parser (15000 lines target)

What This Layer Does

Tree-sitter / GLR incremental parser with error recovery. Parses the rope from Layer 3 into a concrete syntax tree (CST). Re-parses only changed regions on each keystroke — O(edit size * grammar size), not O(file size).

Repos That Contribute

Repo	What to pull
snapkitty-resonance-isa	Abjad VM IR bytecode — maps directly to parser stack machine
snapkitty-resonance-bridge	proof→SUBLEQ encoding — extract as parser IR substrate (EXTRACT)
j-matrix-twin	SUBLEQ attention + WASM (EXTRACT) — alternative parser substrate for browser
systemic-intelligence	GLR skeleton in OCaml section

What to Build First

1. Grammar representation — rule table, terminal/nonterminal IDs (use Layer 0 intern)
2. GLR parse table — state machine over the grammar
3. Incremental reparse — diff the rope edit, re-enter parser at affected range
4. Error recovery — skip/insert tokens, maintain partial tree
5. SUBLEQ substrate port — from j-matrix-twin for WASM browser path
6. Abjad VM IR — from snapkitty-resonance-isa as the hot-path parser stack

Key Design Constraints

• CST nodes in Layer 0 arena; GC via arena reset between full reparses
• Edit regions from Layer 3 rope trigger incremental reparse only
• Grammar tables are WORM-sealed after load (bifrost pattern from Layer 0)
• Parser must run in O(n log n) worst case, not O(n^2)