A Log.* namespace: five levels (trace/debug/info/warn/error), a runtime
threshold, and structured key=value fields, so games get something better than
scattered print calls and release builds can go quiet without touching call
sites.
- Log.trace/debug/info/warn/error(msg, [k, v]...) -> stderr, "[LEVEL] msg k=v"
- Log.set_level(n) show only level >= n (0 = all default, 5 silences all)
- Log.level() read the current threshold
Fields accept strings, ints, and longs (numbers formatted automatically); the
level tag is chosen at compile time so a filtered-out level costs only a
comparison. Writes to stderr, never touching the simulation — no effect on
determinism/replays. v1 is the console sink; rotating-file and in-engine overlay
sinks are noted as follow-ups.
- examples/library/logging.ludic: asserts the set_level/level threshold
round-trip and that every level (with mixed-type fields) runs without faulting;
the stderr gating itself was verified by hand (warn/error emit, lower levels
suppressed). Wired into `x test` (now 53 passed).
- docs: a new Log section + per-symbol pages; inventory and coverage pass.
- seed regenerated; `x bootstrap-cfree` fixpoint holds.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
