装备打孔：递进金锭费用的开孔上限

local function punch(actor)
    local holes = getplayvar(actor, "holes") or 0
    if holes >= 4 then
        sendmsg(actor, 1, "孔位已满 4 个")
        return
    end
    local cost = ({10, 20, 40, 80})[holes + 1]
    setplayvar(actor, "holes", holes + 1)
    sendmsg(actor, 1, "已开第 " .. (holes + 1) ..
        " 孔，花费 " .. cost .. " 金锭")
end

local function queryHoles(actor)
    local holes = getplayvar(actor, "holes") or 0
    sendmsg(actor, 1, "当前 " .. holes .. "/4 孔，下孔费用 "
        .. ({10, 20, 40, 80})[holes + 1] .. " 金锭")
end