CRDT ADT.

get operations return value of this type

CRDT Counter hold a integer Count

>>> Counter 42

Counters can be incremented/decremented

>>> CounterInc 1

CRDT Set is a Data.Set

>>> Set (Data.Set.fromList ["foo","bar"])

CRDT Set operations

CRDT Map is a Data.Map indexed by MapField and holding MapEntry.

Maps are specials in a way that they can additionally hold Flags, Registers, and most importantly, other Maps.

CRDT Map is indexed by MapField, which is a name tagged by a type (there may be different entries with the same name, but different types)

CRDT Map holds values of type MapEntry

Lookup a value of a given MapEntryTag type on a given MapPath inside a map

>>> lookup ("a" -/ "b") MapFlagTag $ { "a"/Map: { "b"/Flag: Flag False } } -- pseudo
Just (MapFlag (Flag False))

map operations It's easier to use mapUpdate:

>>> "x" -/ "y" -/ "z" `mapUpdate` SetAdd "elem"
MapUpdate (MapPath ("x" :| ["y","z"])) (MapCounterOp (CounterInc 1))

Selector (“xpath”) inside Map

Operations on map values

Registers can only be held as a Map element.

Register holds a ByteString.

Registers can be set to a value

>>> RegisterSet "foo"

Flags can only be held as a Map element.

Flag can be set or unset

>>> Flag False

Flags can be enabled / disabled

>>> FlagSet True