Lua状态机：字段表驱动的界面流转

-- 错误：条件嵌套越叠越厚，新状态无从下手
if opened and not fighting then
    showFull()
elseif opened and fighting then
    showMini()
end

local TRANS = {
    closed = {open = "shown"},
    shown  = {hide = "closed", fight = "mini"},
    mini   = {hide = "closed"},
}
local state = "closed"
local function fireEvent(ev)
    local row = TRANS[state]
    local nxt = row and row[ev]
    if nxt == nil then
        return false
    end
    state = nxt
    refreshPanel(state)
    return true
end