interface ILispReader
{
    ITextReader Input { get; set; }
    LispObject Read();
}

interface ITextReader
{
    IBinaryReader Input { get; set; }
    Encoding Encoding { get; set; }
    char Read();
}

interface IBinaryReader
{
    IInputDevice Input { get; set; }
    byte Read();
}

interface IInputDevice
{
    void Read(byte[] buffer, int start, int count);
}