library DamageSystem initializer Init {

#include "cj_types.j"
#include "cj_typesEX.j"

     private constant trigger AddEventTrig = new trigger
     private int iTrig = 0
     private trigger array Take_Trig

     private bool AddEvent_Conditions () {
         return GetUnitAbilityLevel(GetTriggerUnit(),'Aloc') == 0  
     }

    private void AddEvent () {
         int i = 0
             whilenot i == iTrig  {
                 TriggerRegisterUnitEvent ( Take_Trig[++i],GetTriggerUnit(), EVENT_UNIT_DAMAGED)
             }  
     }

     public void RemoveTriggerFromSystem ( trigger t ) {
         int i = 0
         whilenot t == Take_Trig[++i] {}
         --iTrig
         whilenot i == iTrig { Take_Trig[i] = Take_Trig[i++] }
          
     }
      
     public void TriggerRegisterAllUnitDamaged (trigger trg) {
         group g = new group
         unit u
         int i = 0
         GroupEnumUnitsInRect (g,bj_mapInitialPlayableArea,null)
             do {
                 u = FirstOfGroup(g)
                 exitwhen u == null
                 TriggerRegisterUnitEvent ( trg, u, EVENT_UNIT_DAMAGED)
                 GroupRemoveUnit( g, u)
             }
         Take_Trig[++iTrig] = trg
         DestroyGroup(g)
         g = null
     }    

     private void Init () {
         region r = new region
         RegionAddRect( r, bj_mapInitialPlayableArea)
         TriggerRegisterEnterRegion( AddEventTrig, r, null)
         TriggerAddCondition( AddEventTrig, Condition(function AddEvent_Conditions))
         TriggerAddAction(AddEventTrig,function AddEvent)
         r = null
     }
}

call TriggerRegisterEnterRegion(CreateTrigger(), r, Filter(function Trig_Test_Actions))