【高级技巧】循环引用序列化：自引用表的字符串输出

local function serialize(tbl, indent, seen)
    indent = indent or 0
    seen = seen or {}
    if seen[tbl] then
        return "[circular]"
    end
    seen[tbl] = true
    local pad = string.rep("  ", indent)
    local parts = { "{\n" }
    for k, v in pairs(tbl) do
        if type(v) == "table" then
            parts[#parts + 1] = pad .. "  " .. tostring(k) .. " = " ..
                serialize(v, indent + 1, seen) .. ",\n"
        else
            parts[#parts + 1] = pad .. "  " .. tostring(k) ..
                " = " .. tostring(v) .. ",\n"
        end
    end
    parts[#parts + 1] = pad .. "}"
    return table.concat(parts)
end

local function dumpGear(actor, gearTree)
    actor = getplayerbyname(actor)
    sendmsg(actor, 1, serialize(gearTree, 0))
end