package UnitIndexer

import OnUnitEnterLeave

public function unit.getIndex() returns integer
	return this.getUserData()

public function unit.toUnitIndex() returns UnitIndex
	UnitIndex instance = this.getUserData() castTo UnitIndex

	if (instance == null)
		instance = new UnitIndex(this)

	return instance

public function unit.getUnitIndexInstance() returns UnitIndex
	return this.toUnitIndex()

public class UnitIndex
	protected unit _unit

	function getUnit() returns unit
		return this._unit

	function getIndex() returns int
		return this castTo int

	construct(unit whichUnit)
		this._unit = whichUnit
		this._unit.setUserData(this castTo int)

	ondestroy
		this._unit.setUserData(0)


// Auto instanciation/destruction
init
	onEnter(() -> new UnitIndex(getEnterLeaveUnit()))
	onLeave(() -> destroy getEnterLeaveUnit().toUnitIndex())