local function serialize(t, knownTables)
    assert(type(t) == "table", "Table expected got: " .. type(t))

    local knownTables = knownTables or {}
    local serialized = ""
    local value

    for k, v in pairs(t) do
        local varType, value = type(v)
        if varType == "string" then
            value = string.format("%q", v)
        elseif varType == "number" or varType == "boolean" or varType == "nil" then
            value = tostring(v)
        elseif varType == "table" then
            local t = v
            for k, v in pairs(knownTables) do
                if v == t then
                    error("Recursive table")
                end
            end
            table.insert(knownTables, v)
            value = serialize(v, knownTables)
        end
        if value then
            local prefix = serialized == "" and "" or ", "
            local key = ""
            if not (type(k) == "number" and k <= #t) then
                key = (type(k) == "number" and "[" .. k .. "]" or k) .. " = "
            end
            serialized = serialized .. prefix .. key .. value
        end
    end
    return  "{" .. serialized .. "}"
end