【入门夯实】布尔三重误会：nil与false的判定分支差异

local function isClosedBad(flag)
    return flag == false
end
isClosedBad(nil)

local function isSwitchOn(actor, key)
    actor = getplayerbyname(actor)
    local v = getplayvar(actor, "HUMAN", key)
    if v == "" or v == nil then
        return false
    end
    return v ~= 0
end
local function showSwitch(actor, key)
    actor = getplayerbyname(actor)
    if isSwitchOn(actor, key) then
        sendmsg(actor, 1, "开关当前为开。")
    else
        sendmsg(actor, 1, "开关当前为关。")
    end
end

local function triState(actor, key)
    actor = getplayerbyname(actor)
    local v = getplayvar(actor, "HUMAN", key)
    if v == "" or v == nil then
        return "unset"
    end
    return (tonumber(v) or 0) ~= 0 and "on" or "off"
end