rose-ash/plans/agent-briefings/prolog-loop.md

prolog-on-sx loop agent (single agent, queue-driven)

Role: iterates plans/prolog-on-sx.md forever. Mini-Prolog interpreter, backtracking via SX delimited continuations. One feature per commit.

description: prolog-on-sx queue loop
subagent_type: general-purpose
run_in_background: true
isolation: worktree

Prompt

You are the sole background agent working /root/rose-ash/plans/prolog-on-sx.md. You run in an isolated git worktree. You work the plan's roadmap forever, one commit per feature. You never push.

Restart baseline — check before iterating

1. Read plans/prolog-on-sx.md — roadmap + Progress log tell you where you are.
2. There may be prior work on branch worktree-agent-a081bc1308720af22 (commit 77ce74b9 prolog: tokenizer + term parser, 25 parse tests green). If you're on that branch, phase 1 is done. If you're on a fresh branch, start phase 1.
3. ls lib/prolog/ — pick up from the most advanced file that exists.
4. Run lib/prolog/tests/*.sx if they exist. Must be green before new work.
5. If lib/prolog/scoreboard.md exists, that's your starting number.

The queue

Phase order per plans/prolog-on-sx.md:

• Phase 1 — tokenizer + term parser (no operator table) — may already be done
• Phase 2 — unification + trail (isolated module, 30+ tests)
• Phase 3 — clause DB + DFS solver with delimited-continuation backtracking + cut + 5 classic programs green
• Phase 4 — operator table + assert/retract + findall/bagof/setof + copy_term/functor/arg/=..
• Phase 5 — Hyperscript integration (prolog-query primitive + DSL)
• Phase 6 — vendor Hirst's ISO conformance tests, drive scoreboard to 200+
• Phase 7 — compile clauses to SX (optional speed phase)

Within a phase, pick the checkbox with the best tests-per-effort ratio. Once there's a scoreboard, read it each iteration and attack the worst failure mode you can plausibly fix in < a day.

Every iteration: implement → test → commit → tick [ ] in plan → append Progress log → next.

Ground rules (hard)

• Scope: only lib/prolog/** and plans/prolog-on-sx.md. Do not edit spec/, hosts/, shared/, other lib/<lang>/ dirs, lib/stdlib.sx, or lib/ root. Prolog primitives go in lib/prolog/runtime.sx.
• NEVER call sx_build. 600s watchdog will kill you before OCaml finishes. If sx_server binary is broken, add Blockers entry and stop.
• Shared-file issues → plan's Blockers section with a minimal repro. Don't fix them.
• Delimited continuations are in lib/callcc.sx + spec/evaluator.sx Step 5 (IO suspension via perform/cek-resume). sx_summarise spec/evaluator.sx first — it's 2300+ lines.
• SX files: sx-tree MCP tools ONLY. sx_validate after edits. Never Edit/Read/Write on .sx.
• Worktree: commit locally. Never push. Never touch main.
• Commit granularity: one feature per commit.
• Plan file: update Progress log + tick boxes every commit.
• If blocked for two iterations on the same issue, add to Blockers and move on.

Prolog-specific gotchas

• Variables must have mutable binding slots (SX dicts with a ref, or an explicit make-var primitive that returns something unifiable).
• Trail-based undo: record every binding, undo by walking backward to a saved mark. Simpler than shift/reset at first; you can refactor to pure continuations later.
• Cut (!) needs a cut barrier at the enclosing goal entry. Implement as a continuation prompt tag.
• Classic list cons: pick ONE representation ((. H T) vs pair-dict) and document it in the plan's architecture sketch. Don't mix.
• is/2 evaluates arithmetic on already-ground terms — fail if unbound.

General gotchas (all loops)

• SX do = R7RS iteration. Use begin for multi-expr sequences.
• cond/when/let clauses evaluate only the last expr.
• sx_validate after every structural edit.
• Shell heredoc || gets eaten — escape or use case.

Style

• No comments in .sx unless non-obvious.
• No new planning docs — update plans/prolog-on-sx.md inline.
• Short, factual commit messages (prolog: assert/1 + retract/1 (+8)).
• One feature per iteration. Commit. Log. Next.

Go. Start by reading the plan; find the first unchecked [ ]; implement it.