Warcarft 3 jass group

local group g = CreateGroup()
local unit f
call GroupEnumUnitsInRange(g,x,y,400.,null)
loop
   set f = FirstOfGroup(g)
   exitwhen f == null
if IsUnitEnemy(f,GetOwningPlayer(u)) and GetWidgetLife(f)>0 and IsUnitType(f, UNIT_TYPE_STRUCTURE) == false and  IsUnitType(f , UNIT_TYPE_MAGIC_IMMUNE) == false   then
    call UnitDamageTarget(u,f,dmg,true,false,ATTACK_TYPE_NORMAL, DAMAGE_TYPE_NORMAL,null)
    call DestroyEffect(AddSpecialEffectTarget("Objects\\Spawnmodels\\Human\\HumanBlood\\HumanBloodFootman.mdl", f, "chest"))
    call DestroyEffect(AddSpecialEffect("Chain Impale.mdx",GetUnitX(f),GetUnitY(f)))
    endif
    call GroupRemoveUnit(g,f)
endloop
    call DestroyGroup(g)
set g =null