材料替换：合成材料的等价替换表

local function check(mats)
    for k, v in pairs(RECIPES) do
        -- 只认固定材料名，缺货即卡死
    end
end

-- 替换表：左边缺货材料，右边替代品与换算比
local SUB = {秘银 = {name = "精金", rate = 2}}
local function hasOrSub(name, need, bag)
    if bag[name] and bag[name] >= need then return true end
    local sub = SUB[name]
    return sub and (bag[sub.name] or 0) >= need * sub.rate
end
sendmsg(actor, 1, "替代校验："
    .. tostring(hasOrSub("秘银", 4, {精金 = 8})))