Data.DAWG.Int

The module implements directed acyclic word graphs (DAWGs) internaly represented as minimal acyclic deterministic finite-state automata. The implementation provides fast insert and delete operations which can be used to build the DAWG structure incrementaly.

See the Data.DAWG.Ord module if you look for a more generic solution (which, for the moment, lacks some of the functionality provided here, e.g. the delete function).

DAWG type

data DAWG

A directed acyclic word graph (DAWG), which can be seen as a map from keys (sequences of Sym's) to values Val. See Data.DAWG.Ord for a more generic version of DAWGs.

Instances

Eq DAWG

Ord DAWG

Show DAWG

type ID = Int

Identifier of a DAWG node (automaton state).

type Sym = Int

A transition symbol.

type Val = Int

A type of DAWG values, stored in accept states.

root :: DAWG -> ID

The root (start state) of the DAWG.

Query

lookup :: [Sym] -> DAWG -> Maybe Val

Find value associated with the key.

numStates :: DAWG -> Int

Number of states in the automaton.

numEdges :: DAWG -> Int

Number of transitions in the automaton.

Traversal

value :: ID -> DAWG -> Maybe Val

Value stored in the given automaton state.

edges :: ID -> DAWG -> [(Sym, ID)]

A list of outgoing edges (automaton transitions).

follow :: ID -> Sym -> DAWG -> Maybe ID

Follow a transition with the given symbol from the given state.

Construction

empty :: DAWG

Empty DAWG.

fromList :: [([Sym], Val)] -> DAWG

Construct DAWG from the list of (key, value) pairs.

fromListWith :: (Val -> Val -> Val) -> [([Sym], Val)] -> DAWG

Construct DAWG from the list of (key, value) pairs with a combining function. The combining function is applied strictly.

fromLang :: [[Sym]] -> DAWG

Make DAWG from the list of words (by annotating each word with a dummy value).

Insertion

insert :: [Sym] -> Val -> DAWG -> DAWG

Insert the (key, value) pair into the DAWG.

insertWith :: (Val -> Val -> Val) -> [Sym] -> Val -> DAWG -> DAWG

Insert with a function, combining new value and old value. insertWith f key value d will insert the pair (key, value) into d if key does not exist in the DAWG. If the key does exist, the function will insert the pair (key, f new_value old_value).

Deletion

delete :: [Sym] -> DAWG -> DAWG

Delete the key from the DAWG.

Conversion

assocs :: DAWG -> [([Sym], Val)]

Return all key/value pairs in the DAWG in ascending key order.

keys :: DAWG -> [[Sym]]

Return all keys of the DAWG in ascending order.

elems :: DAWG -> [Val]

Return all elements of the DAWG in the ascending order of their keys.