Module battle 

Battle system trait definitions for a JRPG engine framework.

This module defines the core abstractions for turn-based battle systems: battle state, battler state, type charts, AI decision-making, and move effect handling. All types are generic over a BattleProvider implementation — the engine is game-agnostic.

Architecture

• BattleProvider — Central trait supplying battle data, damage formula, and factory methods. All methods take &self (read-only provider).
• TypeChart — N×N type effectiveness matrix, parameterized by game types.
• BattleAI — Move selection, switching, and item-use decisions.
• EffectHandler — Dispatches move effects (damage, healing, status, stat changes) on battler state.

Design Principles

• Generic over game data — No concrete game-specific, monster, or move types. All identifiers are associated types on BattleProvider.
• Provider pattern — Battle systems query the provider, which delegates to type charts, AI, and effect handlers internally.
• No I/O, no platform — Pure data and trait definitions only.

Re-exports

pub use ai::BattleAi;

pub use ai::BattleAiProvider;

pub use driver::BattleDriver;

pub use driver::BattleEnd;

pub use driver::TurnEvent;

pub use driver::TurnOutcome;

pub use rng::BattleRng;

Modules

ai

Generic, game-agnostic battle AI driver (P0c).

driver

Generic, game-agnostic battle turn-execution driver (P0b).

rng

Injected randomness for the battle turn-execution driver (P0b).

stack

Showdown-style effect-stack battle engine (Pattern C) — vertical-slice POC (design doc 06-battle-engine-effect-stack-design.md, §8).

Structs

BattleState

The complete state of an ongoing battle.

BattlerRef

A reference to one battler position on the battlefield.

BattlerState

The battle state of a single monster/character.

DamageResult

Result of a damage calculation.

EnumMap

A map from enum-like keys to values, backed by a Vec of (K, V) pairs.

OrderKey

A turn-ordering sort key produced by BattleProvider::turn_order_key.

ResourcePool

A per-battler pool of generic, game-defined consumable resources (MP / SP / TP / mana / charge — the engine assigns the concept no name; doc 13 §4, the highest-value STATE-SEAM).

Enums

BattleAction

The action a battler has chosen to take this turn.

EffectResult

Outcome of applying a move effect.

MoveEffect

Categories of additional effects a move can have.

MoveGate

Result of BattleProvider::before_move: the pre-move status gate.

Terrain

Field terrain condition.

Weather

Field weather condition.

Traits

BattleAI

AI decision-making for battle actions.

BattleProvider

Central trait for battle system data and formula implementations.

EffectHandler

Handles move effects on battler state.

TypeChart

N×N type effectiveness matrix.