Unity Composition Pattern

Unity Composition Pattern

A fundamental design skill to prevent "Inheritance Hell." This pattern replaces 10 specific classes (e.g., RedStone, GoldStone) with one generic class that composes behaviors from ScriptableObject assets.

Core Features

1. Has-A Logic: Objects define their properties through members (Configs) rather than their base class type.
2. SO-to-Runtime Bridge: Uses ScriptableObjects as static data templates that generate dynamic runtime instances.
3. Tuple Deconstruction: Uses C# ValueTuples to return multi-part data from composite objects without extra boilerplate.
4. Hierarchy Flattening: Drastically reduces the number of C# files needed by offloading variations to Project Assets.

Core Files (Max 3)

• EntityConfigSO.cs.txt: Base class for creating interchangeable data packets.
• ModularEntity.cs.txt: The generic container that holds one or more configurations.
• CompositionExample.cs.txt: Demonstrates resource harvesting with Tuple destructuring.

Usage

1. Identify "Is-A" vs "Has-A"

• Bad: ElectricCar : Car : Vehicle (Inheritance)
• Good: Vehicle has an EngineConfig (Composition)

2. Multi-Value Returns (Tuples)

Instead of internal state-tracking:

public (int gold, int weight) Gather() => (10, 5);
// Client destructures instantly:
var (g, w) = node.Gather();

3. Strategy via SO

Attach different EntityConfigSO assets to the same ModularEntity to change its identity in the Inspector.