feat(parser): ADR-0122 rate/per-unit grammar (substrate-only; lift deferred)
First parser-expansion ADR after ADR-0121's deferral. Adds the rate
algebra substrate (Rate dataclass + apply_rate operation kind + parser
pattern + solver/verifier/realizer + en_arithmetic_v1 pack lemma)
mirroring the deferral pattern that ADR-0121 demonstrated for
capability promotion: substrate complete, gate refuses honestly.
Substrate
- Rate(value, numerator_unit, denominator_unit) frozen dataclass with
strict positive-value + non-empty-distinct-unit refusal at construction
- apply_rate operation kind admitted in VALID_OPERATION_KINDS;
Operation.operand widened to Quantity | Rate with kind-discriminated
type enforcement
- Parser: _RATE_COST_EACH_RE + _RATE_COST_EACH_TRAILING_RE +
_Q_RATE_AGGREGATE_RE patterns; actor_units state tracking;
first-declaration-wins on redeclaration (ParseError); orphan-rate
refusal at end of parse; three refusal paths in rate-aggregate question
- Solver: _apply_rate() reads denominator-unit state, multiplies by
rate.value, writes numerator-unit state (denom preserved)
- Verifier: _verify_apply_rate_step() byte-equal replay
- Realizer: 'At {N} {numer} per {denom_singular}, {actor} spends ...'
template containing required tokens
- Pack: en-arith-006 apply_rate lemma + gloss; SHA-256 checksums
refreshed; manifest version 1.0.0 -> 1.1.0; provenance tagged
adr-0122:rate_extension:2026-05-22
Measurement (honest)
- Sealed GSM8K correct_rate: 0/1319 (substrate matches zero real cases
alone). Multi-construction barrier documented in the ADR: all 14 sealed
cases matching 'each \w+ costs?' combine rate with at least one other
class (aggregation 6, comparison 3, unit conversion 2, multi-actor 2,
conditional 1)
- Sealed GSM8K wrong: 0 (load-bearing positive claim; grammar adds zero
misparses across 1,319 real test problems)
- Anti-overfit lanes unchanged: OOD ratio, perturbation invariance
preserving/breaking 1.0, adversarial wrong 0
- ADR-0121 invariants byte-equal preserved (6/6)
- 41 new ADR-0122 invariants pinned in tests/test_adr_0122_rate_per_unit.py
- 670 existing math + pack regression tests pass
Roadmap update
- Per-ADR lift expectation corrected: no single parser-expansion ADR
will move sealed correct_rate alone. First lift signal will come
from cumulative composition after 3rd or 4th class lands (rate +
comparison + aggregation foundational set)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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