Supported Fields

  • type: simple instance of a native type or a struct.
  • struct: complex organization of types, structs, and lists. The "root" value of any binary block definition is a struct.
  • list: single dimension series of one kind of type or struct.
  • enum: enumerated list of values.

Native Types

  • byte: 8 bit unsigned integer value.
  • char: UTF-8 encoded character value.
  • sint: 32 bit signed integrer value.
  • uint: 32 bit unsigned integer value.
  • slong: 64 bit signed integer value.
  • ulong: 64 bit unsigned integer value.
  • single: 32 bit floating point value
  • double: 64 bit floating point value.
  • string: UTF-8 encoded array of character values.
  • timestamp: 64 bit signed integer which represents the number of milliseconds before or after 01-01-01 00:00:00Z. Effective range is roughly 500 million years ranging from 250,000,000 BCE to 250,000,000 CE.
  • timespan: 64 bit unsigned integer which represents a number of elapsed Ticks Effective range is roughly 584,542 years.
  • blob: efficient storage of an array of bytes up to 2GB (2^31 bytes) in size.
  • guid: 16 byte blob value.

Tag Structure

    byte0 = Type Identifier
    byte1 = MemberOrdinal
    byte2 = MemberOrdinal
    byte3 = Annotation

!! NOTE: namespace, struct, and type names can only contain letters, numbers, and underscores and cannot begin with a number. !!



Namespace declariations scope all struct definitions with in a given definition file. Only a single namespace can be defined per definition file; more than one definition file can share a single namespace.

NOTE: A definition file without a namespace declaration will assume the empty namespace.


Struct declcarations are in the format of the "struct" keyword followed by the name of the struct, followed by the definition of the struct bookended in a pair of braces "{ }".

struct <struct name>

Structs should contain a number of members, each suffixed with a ordinal. The ordinal is the unqiue identifier for the member within this struct definition.

Generally ordinals begin with 1, but can be any integer 1 to 65536. This limits the number of members a struct can contain to 65,536.

NOTE: A struct without any member types will be ignored by the compiler.


Enum delcarations are in the format of the "enum" keyword followed by the name of the enumeration and a bracketed list of the enumeration's values. Enumeration values are comma seperated and must be assigned literal values as needed.

Enumerations use a 32 bit signed storage type which allows for literal values ranging from -2,147,483,648 to 2,147,483,647.

enum <enumeration name>
    <value name> = <literal value>,


Type declarations are in the format of the "type" or "list" keyword followed by either a native type or the name of a customed defined struct, followed by the the name of the member.

Each member must be suffixed with an unique ordinal. Each member definition must be terminated with a semi-colon.

<type or list keyword> <native, struct, or enum name> <member name> = <ordinal> [<annotation>];

Annotations have no runtime impact on binary block serialization or deserialization, but are useful for offline contract analysis and improving testability.

Visualization of Serialized Data

Serialized String

Serialized 64-bit Integer

Serialized List of 32-bit Integers

Last edited Apr 2, 2014 at 5:47 AM by focuspark, version 20


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