Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn: You can discard 1 card, then target 1 Attack Position monster your opponent controls; destroy that target.
--サイバー・ジムナティクス
--Cyber Gymnast
local s,id=GetID()
function s.initial_effect(c)
	--destroy
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_DESTROY)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1)
	e1:SetCost(s.descost)
	e1:SetTarget(s.destg)
	e1:SetOperation(s.desop)
	c:RegisterEffect(e1)
end
function s.descost(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
	Duel.DiscardHand(tp,Card.IsDiscardable,1,1,REASON_COST|REASON_DISCARD)
end
function s.filter(c)
	return c:IsPosition(POS_FACEUP_ATTACK)
end
function s.destg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsControler(1-tp) and chkc:IsLocation(LOCATION_MZONE) and s.filter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,0,LOCATION_MZONE,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_DESTROY)
	local g=Duel.SelectTarget(tp,s.filter,tp,0,LOCATION_MZONE,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_DESTROY,g,1,0,0)
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsPosition(POS_FACEUP_ATTACK) and tc:IsRelateToEffect(e) then
		Duel.Destroy(tc,REASON_EFFECT)
	end
end