agent: builder model: sonnet max_turns: 120 budget_usd: 20 —

Brief: E11-4b, statements and blocks of `emit` in Nikaia (Part of #583)

Score: S=2 (moves about 1500 Rust lines), O=1 M, C=15 M (E11-4a: 1212 lines in one run; check moves 8-15 k tokens per line), self-hosting lane 1 (docs/priorities.md).

Facts

E11-4a (ab603477) made Emitter::expr a thin adapter over emit_expr (tools/emit_expr.nika); statements and blocks are still Rust and reached from Nikaia through the host’s stmt / block_* callbacks.
Plan: docs/selfhosting-plan.md, E11-4 split and E11-4a switched (read those two paragraphs only). Pattern to copy: tools/emit_expr.nika + its adapter in emit/mod.rs.

Locations (at a2f40f98; re-grep, lines shift)

crates/nikaia/src/emit/mod.rs: a_counted_turn 2222, block 2226, block_opening_with 2257, block_plain 2314, never_negative, filled_at_once, branch_pauses, hold_temporaries, stmt 2567, stmt_written 2603, makes_a_map 2634, a_stmt 2656-3611, around_value, handed_back, returns_either (to 3662).
Host: crates/nikaia/src/emit/host.rs, tools/emit_host.nika. Known facts: docs/builder-facts.md. Names: nikaia run scripts/where.nika -- NAME.

To build

rs2nika draft of the range (crates/rs2nika/convert, --profile emit); report rs2nika: kept N of M lines.
tools/emit_stmt.nika: emit_stmt, emit_block_plain, emit_block_opening_with and the helpers only they call; prefix names emit_stmt_. A callee not yet moved goes through a host method.
Switch: Emitter::stmt / block_plain / block_opening_with become thin adapters; delete the moved Rust and the dead locals; add the file to scripts/self_hosting.py.
A lowering defect met: fix in the compiler with a tests/compiler/ test, own commit (or file a ready issue and stop).
cargo build --profile fast -p nikaia, target/fast/nikaia lower-std: output unchanged beyond the slice’s files; run cargo test --profile fast -p nikaia --test it -- emit:: and sysroot. Add the E11-4b switched paragraph to docs/selfhosting-plan.md. Commit says Part of #583, Fixes #<this>.

Rules (CLAUDE.md)

develop in the main checkout; git add <files> only; push fast-forward, no rebase. Commit after each finished step.
Before pushing: cargo fmt, cargo clippy --all-targets -- -D warnings, scripts/pre-push-check.sh.
No version lines, CHANGELOG.md, badges; no new NK code. New tests in Nikaia only; never the full suite.
Do not touch other agents’ uncommitted files (git status at start).
NIKAIA_CACHE_LIMIT=2G; at most two clones with target/; delete target/release/nikaia-scratch after tests; report GB freed. Scripts in files, small reads, no foreground sleep.

Report (at most 15 lines, `<brief path>.report.md`)

Result, Files, Commit, Fixes, Pushed, Tests, Deviation, Found, Needs, rs2nika kept N of M, Rust lines removed, GB freed, Owner (form: docs/architect.md, Briefs and reports).

This site is open source. Improve this page.

Brief: E11-4b, statements and blocks of emit in Nikaia (Part of #583)