NULL_ENTITY = entity(0)

function deepcopy(orig)
    local orig_type = type(orig)
    local copy
    if orig_type == 'table' then
        copy = {}
        for orig_key, orig_value in next, orig, nil do
            copy[deepcopy(orig_key)] = deepcopy(orig_value)
        end
        setmetatable(copy, deepcopy(getmetatable(orig)))
    else -- number, string, boolean, etc
        copy = orig
    end
    return copy
end

function table:merge(table1, table2)
    local newTable = deepcopy(table1)

    for k, v in pairs(table2) do
        newTable[k] = v
    end

    return newTable
end