Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
2 Level 4 monsters When this card is Xyz Summoned: You can discard any number of cards; increase this card's Rank by the number of discarded cards. Once per turn, while this card has Xyz Material: You can target 1 monster in your GY; detach all materials from this card, and if you do, attach that target to this card as material. When a monster is attached by this effect, this card's Type and Attribute become the same as that monster's original Type and Attribute.
--外神ナイアルラ
--Outer Entity Nyarla
local s,id=GetID()
function s.initial_effect(c)
	--xyz summon
	Xyz.AddProcedure(c,nil,4,2)
	c:EnableReviveLimit()
	--rankup
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_SPSUMMON_SUCCESS)
	e1:SetCondition(s.rkcon)
	e1:SetCost(s.rkcost)
	e1:SetOperation(s.rkop)
	c:RegisterEffect(e1)
	--attach
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetType(EFFECT_TYPE_IGNITION)
	e2:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e2:SetCountLimit(1)
	e2:SetRange(LOCATION_MZONE)
	e2:SetCondition(s.condition)
	e2:SetTarget(s.target)
	e2:SetOperation(s.operation)
	c:RegisterEffect(e2)
end
function s.rkcon(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsXyzSummoned()
end
function s.rkcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsDiscardable,tp,LOCATION_HAND,0,1,nil) end
	local ct=Duel.DiscardHand(tp,Card.IsDiscardable,1,60,REASON_COST|REASON_DISCARD)
	e:SetLabel(ct)
end
function s.rkop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if c:IsFaceup() and c:IsRelateToEffect(e) then
		local e2=Effect.CreateEffect(c)
		e2:SetType(EFFECT_TYPE_SINGLE)
		e2:SetCode(EFFECT_UPDATE_RANK)
		e2:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE)
		e2:SetValue(e:GetLabel())
		c:RegisterEffect(e2)
	end
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return e:GetHandler():IsType(TYPE_XYZ) and e:GetHandler():GetOverlayCount()>0
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_GRAVE) and chkc:IsControler(tp) and chkc:IsMonster() end
	if chk==0 then return Duel.IsExistingTarget(Card.IsMonster,tp,LOCATION_GRAVE,0,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TARGET)
	local g=Duel.SelectTarget(tp,Card.IsMonster,tp,LOCATION_GRAVE,0,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_LEAVE_GRAVE,g,1,0,0)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	local tc=Duel.GetFirstTarget()
	if c:IsRelateToEffect(e) and tc:IsRelateToEffect(e) then
		local og=c:GetOverlayGroup()
		if #og==0 then return end
		Duel.SendtoGrave(og,REASON_EFFECT)
		Duel.Overlay(c,tc)
		if c:IsFacedown() then return end
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetProperty(EFFECT_FLAG_COPY_INHERIT)
		e1:SetCode(EFFECT_CHANGE_ATTRIBUTE)
		e1:SetValue(tc:GetOriginalAttribute())
		e1:SetReset(RESET_EVENT|RESETS_STANDARD_DISABLE)
		c:RegisterEffect(e1)
		local e2=e1:Clone()
		e2:SetCode(EFFECT_CHANGE_RACE)
		e2:SetValue(tc:GetOriginalRace())
		c:RegisterEffect(e2)
	end
end