Result: done
Files: crates/nikaia-std/src/tools/modules.nika crates/nikaia-std/src/tools/lowered/modules.rs crates/nikaia-std/src/tools/lowered.rs crates/nikaia/src/modules.rs docs/selfhosting-plan.md
Commit: modules: the program’s ledgers and its emission into Nikaia (M3b)
Body: Program::of and Program::emit_reading keep their Rust signatures and forward to modules_program_of over ModulesProgramHost and modules_emit_reading over ModulesEmitHost (tools/modules.nika). Nikaia now holds the ledger assembly (dependency ledgers, the std_alone / one-group rule for own_checked, absorb_own), the trust decision (keyed packages matched by the last :: segment, both barrier rules), the header, the loop that skips dependency units and the abort table. Rust does the test-block retain and type_rules::across_files before the call, because they change the units in place and Parsed stays Rust. The program host also gives empty_ledger and std_library (Ledger::empty and std_library are not Nikaia yet), and it keeps the last own group’s checked units and the noted pauses, with unit += from. The emit host keeps the source map, published and the anyhow refusal of a unit that does not lower; that refusal is handed back unchanged, so its rendering and type stay byte for byte. The trait parameter keyed_functions(package: ref String) is ref because a body-less trait method’s String reads as owned. Self-hosting share: 82.2 % (unchanged at one decimal).
Part: #125
Tests: it modules package map_ trust dependency result_source examples + guard set: 311 passed; nikaia test --project tests/compiler: 243 passed; lower-std fixpoint after one build (only lowered/modules.rs and the index changed); clippy clean; pre-push-check ok; no test added (pure move, no fix)
Gate: green
Deviation: none
Found: in a tools/.nika file, a mutable local set from a text literal and then changed in place (let mut out = "a" then out.push_str("b"), return out) is refused with NK1125 *A String? may be missing and NK1104 returning String?. A user program run with nikaia run accepts the same lines. Probe: add pub fn modules_probe_a() -> String { let mut out = "a"; out.push_str("b"); return out } (one statement per line) to modules.nika and run nikaia lower-std. The type : String written on the local gets past it, and that is the house spelling (445 uses). The refusal message is still wrong. Worth an issue.
Needs: none
Changelog: none
Owner: none
Disk freed: 0
Rs2nika: kept 5 of 73 lines (under 60 %). The three costliest edits: 1) the draft’s impl Program methods work on Vec[Unit], Parsed, SourceMap and the emitter’s Rust calls, so every body had to be rewritten as host calls by unit index (the brief’s design); 2) the labelled 'packages: loop over a BTreeMap[&str, Vec[Parsed]] came out as a TODO, rewritten as a BTreeSet of names with break; 3) iter_mut, SourceMap::default() and map_err with refusal_at have no Nikaia form, so they stayed Rust inside the host
Pushed: 093923cfa5eef56a131a8631c71c1c2790e57618
