feat(parser): source-anchored combat-relationship subject static (Alms Beast)

[nickmopen]

Problem

A self-relative combat-relationship subject failed to parse — Alms Beast: Creatures blocking or blocked by ~ have lifelink. No subject-filter arm recognized the blocking or blocked by <self> qualifier, so the whole static line dropped (static_structure Unimplemented).

The target-relative form (… blocking or blocked by target creature) is already parsed in oracle_target; only the self/source-relative static form was missing.

Fix

Strip the trailing blocking or blocked by ~ / blocking or blocked by this creature qualifier in parse_continuous_subject_filter, parse the base subject recursively, and attach a source-anchored FilterProp::CombatRelation { relation: BlockingOrBlockedBy, subject: Source }.

That FilterProp (and CombatRelationSubject::Source) is already fully evaluated at runtime by game::filter — so this is a grammar-only seam. The self-reference is normalized to ~; this creature is accepted for the literal phrasing. Mirrors the existing merged qualifier-strip pattern in the same function.

Tests

combat_relation_subject_static_binds_source_anchored_filter asserts (typed AST, both ~ and this creature forms) that the line produces a single static whose affected filter is a creature subject carrying FilterProp::CombatRelation { BlockingOrBlockedBy, Source }, with an AddKeyword { Lifelink } grant.

Local: parser::oracle_static passes; cargo fmt, clippy (-D warnings), parser-combinator + engine-authorities gates all clean.

[gemini-code-assist]

Code Review

This pull request adds support for parsing combat-relationship qualifiers (specifically "blocking or blocked by ~" and "blocking or blocked by this creature") in static abilities, mapping them to a source-anchored FilterProp::CombatRelation. It also includes corresponding unit tests to verify the new parsing behavior. As there are no review comments provided, I have no further feedback to provide.

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[github-actions]

Parse changes introduced by this PR · 1 card(s), 2 signature(s) (baseline: main 1f875c96ecbb)

1 card(s) · static/Continuous · added: Continuous (affects=combat related creature, mods=grant Lifelink)

Examples: Alms Beast

1 card(s) · ability/static_structure · removed: static_structure

Examples: Alms Beast

[matthewevans]

Approving — clean, well-scoped grammar work.

Verified:

• Right seam. This adds the subject: CombatRelationSubject::Source (self-anchored) sibling of the already-parsed target-relative form in oracle_target.rs (which uses subject: ParentTarget) — same FilterProp::CombatRelation, different anchor. It's a grammar-only change.
• Runtime authority pre-exists. game::filter already evaluates CombatRelationSubject::Source (filter.rs:3302) and CombatRelation::BlockingOrBlockedBy (filter.rs:3318), so the parsed filter is live at runtime — no new engine logic, no inert AST.
• Combinators + suffix discipline. all_consuming(terminated(take_until(needle), tag(needle))) correctly requires the qualifier to be a true trailing suffix, and the recursion into parse_continuous_subject_filter(base) composes the base subject with the added prop.
• Discriminating test asserts the typed structure (creature subject + source-anchored BlockingOrBlockedBy prop + lifelink grant) for both the normalized ~ and literal "this creature" phrasings — not a Debug-string dump.

Thanks — nicely mirrors the existing pattern for the static-subject case.