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Registries and Content

Generic registry

src/registry.rs defines one Registry<K> used for four content families. K: ContentKind declares factory argument and output types. Each registered definition stores:

Interned stable string name.
Dense, type-distinct Id<K>.
Display name.
Integer priority.
Send + Sync factory closure.

stable name --intern--> u32 | +--> Id<WeaponContent> +--> Id<EnemyContent> +--> Id<DamageContent> +--> Id<StatusContent>

The marker type makes IDs with equal numeric indices incompatible across registries. Manual Copy, Eq, Hash, and Debug implementations avoid imposing trait bounds on the zero-sized marker.

Operations and constraints

Operation	Behavior
`register`	Intern name, insert/replace definition, append ID to `all`
`make`	Index definition and invoke factory; invalid ID panics
`display_name` / `priority`	Index definition; invalid ID panics
`id_of`	Resolve stable name, returning `Option`
`all`	Return IDs in registration order

Registering the same name twice reuses the ID and replaces the definition but appends a duplicate ID to all. There is no duplicate guard, removal, versioning, serialization, mod loading, or registry-wide sort.

Content families

Registry	Factory input	Factory output	Seeded definitions
Weapon	tier `u32`	boxed `ProjectileBehavior`	`impact`, `poison_coating`
Enemy	tier `u32`	`Enemy`	`blob`
Damage	potency `u32`	boxed `DamageBehavior`	`physical`, `poison`
Status	tier `u32`	boxed `StatusBehavior`	`poison`

Weapons

WeaponRegistry::new first resolves physical and poison IDs from the already-built damage registry, then captures those typed IDs in factories:

Stable name	Display	Factory	Behavior priority
`impact`	Impact	`TowerBaseWeapon::create(tier, physical)`	IMPACT (100)
`poison_coating`	Poison Coating	`PoisonCoating::create(tier, poison)`	DEFAULT (0)

The registry definition priority is currently set to DEFAULT for both entries and is not used when assembling a shot. Actual behavior objects report their own priorities and are sorted in src/systems.rs.

Enemies

EnemyRegistry registers only blob. make_kind invokes the factory and stamps the actual EnemyID over EnemyID::PLACEHOLDER. A blob factory computes:

HP = round(1.0 × 1.6^tier)
XP = round(1.0 × 1.3^tier)

It attaches SplitOnDeath::create(3) and SeekCenter::create(0). See src/enemies/blob.rs.

Damage

The damage registry seeds physical and poison behavior factories. The Acid damage behavior exists in src/behavior/damage.rs but is not registered; old integer constants Damage::PHYSICAL and Damage::ACID are also unused. More importantly, registered DamageBehavior::compute objects are never constructed or invoked by live combat. Current damage semantics come from DamageMap plus the enemy resistance map.

Statuses

The status registry seeds a poison factory producing fixed PeriodDamage: amount = 3, one-second interval, five-second lifetime, and Source::None. Its tick formula is (amount / interval) × dt, so this definition deals about 3 damage per second and about 15 over five seconds before resistance (with a possible final-frame overshoot because expiry tests duration > lifetime). Live Poison Coating bypasses this registry and constructs a tier-scaled status directly with the projectile source. Thus StatusRegistry is initialized and stored but not used on the current gameplay path.

Construction order

World::new enforces dependencies manually:

DamageRegistry::new
  -> WeaponRegistry::new(&damage)
  -> EnemyRegistry::new
  -> StatusRegistry::new(&damage)
  -> Tower::new(&weapons)

Missing required stable names panic through expect or unwrap. There is no explicit validation phase.

Crate integration

Weapon offers use weapon_registry.all() and deterministic modulo selection. Three independent rolls allow repeats. An empty registry would panic; the built-in registry is non-empty. A selected ID is passed to Tower::equip, which adds tier 1 or increments the existing tier. Display names come from the registry.

Live, partial, unwired

Live: typed IDs, name lookup, weapon factories at fire time, enemy factory at wave spawn/replication, crate display and selection.

Partial: priority is duplicated between definitions and behavior objects; repeated registration can duplicate catalog entries; constructors assume built-ins exist.

Unwired: damage behavior factories, status factory use in gameplay, dynamic content from Lua/Serde/JSON, external registration, hot reload.

See World and Entities for how IDs are stored and Behavior System for the objects factories produce.