【策划架构】Lua loadstring公式：裁决之杖动态调价的架构封装

local function priceBy(expr)
    local f = loadstring(expr)   -- 裸执行运营字符串
    return f()                   -- 全局环境裸奔
end

local function priceBy(expr)
    local sand = {math = math, tonumber = tonumber,
        tostring = tostring}
    sand._G = sand
    local f = loadstring("return " .. expr)
    if not f then return 15001 end
    setfenv(f, sand)                 -- 5.1 沙箱环境
    local ok, price = pcall(f)
    if ok and price then return math.floor(price) end
    return 15001                     -- 兜底标价
end