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Relations

A relation defines the possible connections between an object and other objects in the Previous Network.

If an object ( x ) is connected to an object ( y ) in relation ( R ), we say ( x ) is ( R )-related to ( y ). ( x ) is called the departure object, and ( y ) is called the destination object.

Operations​

Relate​

Users can call relate(uint256 dest, uint256 dep, uint64 rel) to connect a departure (dep) object to a destination (dest) object.

Unrelate​

Conversely, unrelate(uint256 dest, uint256 dep, uint64 rel) can be called to disconnect them.

Creation​

Relations are registered at the Relation Registry. A relation itself is also an object and consists of two to nine elements, with the first element being possession and the remaining elements being adj_spec0, adj_spec1, ..., adj_spec7.

Possession​

The possession element defines the processing of the ownership of the departure objects when they are connected or disconnected from destination objects.

Adjacency Specs​

Each adj_spec_n element is composed of two tuples: (dep_kind, min, max), (dep_kind, min, max).

  • dep_kind: The kind ID of the departure object, a uint64 integer.
  • min: The minimum number of objects that the destination object can accept, a uint32 integer.
  • max: The maximum number of objects that the destination object can accept, a uint32 integer.

The last tuple (dep_kind, min, max) of the last adj_spec_n can be all zeros, indicating the end of the adjacency spec array.

Normal dep_kinds must be an integer in the range of [1, (2^64 - 2)].

A wildcard dep_kind has a value of 2^{32} - 1, meaning any kind.

The (dep_kind, min, max) tuples must be in increasing order. If a wildcard adjacency spec exists, it must be the last valid one.

min and max can be any uint32 integer in the range [0, (2^32 - 1)], as long as max >= min.

If max equals (2^32 - 1), it means unlimited.