Elixir looks nice

gistfile1.ex

@doc """
Pop the next mode from the stack and return new Status record with the
mode or nil if there were no modes to pop.
"""
def pop(status) do
    [head | tail] = status.mode_stack
    status = status.mode_stack tail

    case head do
        [] -> nil
        _ -> status.current_mode head
    end
end