Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn, if a monster you control would be destroyed by battle, you can send 1 Rock-Type monster from your Deck to the Graveyard instead.
--岩投げエリア
--Catapult Zone
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	c:RegisterEffect(e1)
	--destroy replace
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_CONTINUOUS+EFFECT_TYPE_FIELD)
	e2:SetCode(EFFECT_DESTROY_REPLACE)
	e2:SetRange(LOCATION_FZONE)
	e2:SetCountLimit(1)
	e2:SetTarget(s.destg)
	e2:SetValue(s.value)
	e2:SetOperation(s.desop)
	c:RegisterEffect(e2)
end
function s.dfilter(c,tp)
	return c:IsControler(tp) and c:IsReason(REASON_BATTLE)
end
function s.repfilter(c)
	return c:IsRace(RACE_ROCK) and c:IsAbleToGrave()
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return eg:IsExists(s.dfilter,1,nil,tp)
		and Duel.IsExistingMatchingCard(s.repfilter,tp,LOCATION_DECK,0,1,nil) end
	return Duel.SelectEffectYesNo(tp,e:GetHandler(),96)
end
function s.value(e,c)
	return c:IsControler(e:GetHandlerPlayer()) and c:IsReason(REASON_BATTLE)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TOGRAVE)
	local g=Duel.SelectMatchingCard(tp,s.repfilter,tp,LOCATION_DECK,0,1,1,nil)
	Duel.SendtoGrave(g,REASON_EFFECT)
end