feat(parser): parameterize superlative-property aggregate direction (least/lowest/smallest → Min)

[ntindle]

Summary

Parameterizes the superlative-property suffix combinator in parse_superlative_property_suffix so the aggregate direction is a single alt: greatest/highest/most → AggregateFunction::Max (existing), and least/lowest/smallest → AggregateFunction::Min (new). Both directions feed the same generic superlative_property_filter_prop, so this closes the entire least/lowest/smallest superlative-selection class — over power, toughness, and mana value — across every card that uses the "with the <superlative> <property> among <set>" shape.

No new engine variant. The runtime already ships AggregateFunction::Min (used by values.min() in game/quantity.rs); previously only the Max head was reachable from the parser, so Min selection was a pure parser gap. The Sacrifice/Destroy/return resolvers consume the resulting PtComparison/Cmc filter prop unchanged.

Concretely, The Dining Car's upkeep clause "sacrifice a creature with the least toughness among creatures you control" now parses to a Sacrifice whose target carries a tie-inclusive (Comparator::EQ) PtComparison on toughness bound to Aggregate { function: Min, property: Toughness, filter: creatures you control } — i.e. it selects the least-toughness creature, as the Oracle text specifies.

This was split out of #5651 at matt's request ("GAP A is clean; if you split GAP A out, I'd take it as-is"). GAP B from that branch never touched oracle_target.rs and is not included here — this PR is superlative-direction-only.

Tier: Standard

Files changed

• crates/engine/src/parser/oracle_target.rs

CR references

• CR 208.1 — power and toughness (superlative selection over power/toughness)
• CR 202.3 — mana value (superlative selection over mana value)
• CR 701.21 — Sacrifice (The Dining Car's upkeep least-toughness sacrifice)

Implementation method (required)

Method: not-applicable — single-combinator parameterization split verbatim out of the already-reviewed #5651 branch (matt approved GAP A as-is); reuses an existing runtime AggregateFunction with no new engine variant.

Track

Developer

LLM

Model: claude-opus-4-8
Thinking: high

Verification

• Required checks ran clean, or the exact CI-owned alternative is stated below.

• Gate A output below is for the current committed head.

• cargo fmt --all — clean

• ./scripts/check-parser-combinators.sh <merge-base> — Gate A PASS (see below)

• cargo clippy -p engine -p phase-ai -p engine-wasm --all-targets -- -D warnings — clean (exit 0, no warnings)

• cargo test -p engine -p phase-ai — all pass; new tests superlative_direction_maps_word_to_aggregate_function and superlative_least_toughness_suffix_emits_min_aggregate_pt_comparison green

• cargo run --profile tool --features cli --bin oracle-gen -- data --filter "the dining car|goblin ringleader" — The Dining Car upkeep clause emits Sacrifice + Aggregate { function: Min, property: Toughness, filter: creatures you control }, Comparator::EQ; 0 Unimplemented/Unknown on the fixed clause; Goblin Ringleader fully clean; no regression

Gate A

Gate A PASS head=de39411921ca8a62a5daddec8274100bffced85a base=302fab2fee76251c4ed835dfd8bc20fd3e02ee8a

Anchored on

• crates/engine/src/parser/oracle_target.rs:4658 — the pre-existing value(AggregateFunction::Max, alt((tag("greatest "), tag("highest ")))) head this change lifts into an alt of two value(function, alt(...)) branches (PATTERNS.md §8b cross-product factoring)
• crates/engine/src/parser/oracle_target.rs:4670 — the sibling property alt (Power/Toughness/ManaValue) that already parameterizes the second axis of this combinator, the pattern the direction axis now mirrors

Claimed parse impact

• The Dining Car (upkeep least-toughness sacrifice clause)
• Class-level: every "with the least/lowest/smallest <power|toughness|mana value> among <set>" card

Validation Failures

None.

CI Failures

None.

[gemini-code-assist]

Code Review

This pull request extends the superlative property suffix parser to support minimum superlatives ("least", "lowest", "smallest") mapping to AggregateFunction::Min, alongside the existing maximum superlatives, and adds comprehensive unit tests. The review feedback correctly identifies a violation of Rule R6 regarding a hallucinated Comprehensive Rules (CR) citation in the test comments, where CR 701.21 (drawing a card) was cited instead of CR 701.16 (sacrifice).

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[github-actions]

Parse changes introduced by this PR · 3 card(s), 3 signature(s) (baseline: main 00320e03e3f5)

1 card(s) · ability/Bounce · field target: opponent controls creature → toughness =min toughness of opponent controls creature opponent controls creature

Examples: Bounce Chamber

1 card(s) · ability/Sacrifice · field target: creature → power =min power of you control creature creature

Examples: Witch-king, Bringer of Ruin

1 card(s) · ability/Sacrifice · field target: creature → toughness =min toughness of you control creature creature

Examples: The Dining Car

2 card(s) had Oracle-text changes (errata/reprint) — excluded as non-parser.

[matthewevans]

Verified the parameterized Min/Max superlative parser, current three-card parse diff, and current CI; Gemini’s CR finding is refuted by docs/MagicCompRules.txt (701.21 is Sacrifice).