@namespace ("example")
protocol ExampleProtocol {

    // An opaque type is in fact a byte array of a fixed length.
    fixed LongLongInteger (8);

    // Enum types are integers and can have default value.
    enum SomeEnum { ONE, TWO, THREE } = THREE;

    record SomeRecord {

        // This is really only useful in unions.
        null aNullField;

        // The usual primitive types.
        boolean aBoolean;
        int aSigned32BitInteger;
        long aSigned64BitInteger;
        float aFloat = 0.0;
        double aDouble;
        bytes someBytes;

        /** This is in fact a doc string. */
        string
        @aliases (["anOriginalString", "anEvenMoreOriginalString"])
        aString = "This used to have some other names but not now.";

        // Logical types are supported on top of some standard types.
        @logicalType ("unsignedLong")
        long anUnsigned64BitInteger;

        @logicalType ("decimal")
        @precision (8)
        @scale (2)
        bytes aFixedDecimalPointNumber;

        @logicalType ("UUID")
        string anUUID;

        // Nested records with optional presence.
        SomeRecord? nextRecord;

        // The usual complex types.
        array<string> aStringList = [];
        map<int> aStringToIntMap = { "key" : 0xBAAD };
        union { null, int } anotherOptionalDeclaration = null;

        @deprecated (true)
        int aDeprecatedInteger = 0;

        LongLongInteger aLongLongInteger;
        SomeEnum anEnumValue;
    }

    // Guess how this would get serialized :-)
    record TestRecord { TostRecord r; }
    record TostRecord { TestRecord r; }
}