【Lua实战】load 与字符串脚本：动态规则引擎

---规则的动态装载：字符串编译为函数
RuleEngine.rules = {}

function RuleEngine.load(name, src)
    local fn, err = load(src, "rule_" .. name)
    if not fn then
        Ops.alert("规则编译失败: " .. name .. " " .. tostring(err))
        return false
    end
    local ok, result = pcall(fn)
    if not ok or type(result) ~= "function" then
        Ops.alert("规则执行失败: " .. name)
        return false
    end
    RuleEngine.rules[name] = result
    return true
end

---规则的执行：经验加成的动态公式
function RuleEngine.apply(name, ...)
    local fn = RuleEngine.rules[name]
    if not fn then return ... end
    return fn(...)
end

---规则的沙箱：禁用危险的全局
local SAFE_ENV = {
    math = math, string = string, os = { time = os.time },
    table = table, ipairs = ipairs, pairs = pairs,
}
local function loadSandboxed(name, src)
    local fn, err = load(src, "rule_" .. name, "t", SAFE_ENV)
    if not fn then return false end
    return pcall(fn)
end

---规则的审计：每次装载留痕
function RuleEngine.audit(name, src, operator)
    Ops.log(("规则[%s]由[%s]更新，长度%d")
        :format(name, operator, #src))
    RuleEngine.history[name] = src
end