【框架设计】状态机可视化：状态流转追踪与调试输出设计

local SM = { state = "idle", trans = { idle = { "ready" }, ready = { "run", "idle" }, run = { "done" } } }
local function setState(sm, next)
    local allowed = sm.trans[sm.state]
    if allowed == nil then
        setsysvar("SM_BAD", sm.state .. "->" .. next)
        return false
    end
    for _, s in ipairs(allowed) do
        if s == next then
            sm.state = next
            return true
        end
    end
    setsysvar("SM_BAD", sm.state .. "->" .. next)
    return false
end

local function traceOn(sm)
    sm.trace = sm.trace or {}
    local old = sm.state
    return function(next)
        local ok = setState(sm, next)
        if ok then
            sm.trace[#sm.trace + 1] = old .. "=>" .. sm.state .. "@" .. os.date("%H:%M:%S")
        end
        return ok
    end
end