【高级技巧】中间件模式：请求处理的洋葱模型封装

local function compose(middlewares)
    return function(ctx)
        local function dispatch(i)
            local mw = middlewares[i]
            if not mw then
                return true
            end
            return mw(ctx, function()
                return dispatch(i + 1)
            end)
        end
        return dispatch(1)
    end
end

local chain = compose({
    function(ctx, next)
        if ctx.muted then
            return false
        end
        return next()
    end,
    function(ctx, next)
        ctx.text = string.upper(ctx.text)
        return next()
    end,
    function(ctx, next)
        sendmsg(ctx.actor, 1, ctx.text)
        return true
    end
})
print(chain({ actor = actor, text = "沙巴克集结", muted = false }))