Safe Haskell | None |
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The module implements *directed acyclic word graphs* (DAWGs) internaly
represented as *minimal acyclic deterministic finite-state automata*.

In comparison to Data.DAWG module the automaton implemented here:

- Keeps all nodes in one array and therefore uses much less memory,
- When
`weigh`

ed, it can be used to perform static hashing with`hash`

and`unHash`

functions, - Doesn't provide insert/delete family of operations.

Transition backend has to be specified by a type signature. You can import the desired transition type and define your own dictionary construction function.

import Data.DAWG.Static import Data.DAWG.Trans.Map (Trans) mkDict :: (Enum a, Ord b) => [([a], b)] -> DAWG Trans a Weight b mkDict = weigh . fromList

- data DAWG t a b c
- lookup :: (Enum a, Trans t, Unbox b) => [a] -> DAWG t a b c -> Maybe c
- numStates :: DAWG t a b c -> Int
- index :: (Enum a, Trans t) => [a] -> DAWG t a Weight c -> Maybe Int
- byIndex :: (Enum a, Trans t) => Int -> DAWG t a Weight c -> Maybe [a]
- hash :: (Enum a, Trans t) => [a] -> DAWG t a Weight c -> Maybe Int
- unHash :: (Enum a, Trans t) => Int -> DAWG t a Weight c -> Maybe [a]
- empty :: (Trans t, Unbox b) => DAWG t a b c
- fromList :: (Enum a, MkNode t b) => [([a], b)] -> DAWG t a () b
- fromListWith :: (Enum a, MkNode t b) => (b -> b -> b) -> [([a], b)] -> DAWG t a () b
- fromLang :: (Enum a, MkNode t ()) => [[a]] -> DAWG t a () ()
- freeze :: Trans t => DAWG t a b -> DAWG t a () b
- type Weight = Int
- weigh :: Trans t => DAWG t a b c -> DAWG t a Weight c
- assocs :: (Enum a, Trans t, Unbox b) => DAWG t a b c -> [([a], c)]
- keys :: (Enum a, Trans t, Unbox b) => DAWG t a b c -> [[a]]
- elems :: (Trans t, Unbox b) => DAWG t a b c -> [c]

# DAWG type

# Query

lookup :: (Enum a, Trans t, Unbox b) => [a] -> DAWG t a b c -> Maybe cSource

Find value associated with the key.

# Index

index :: (Enum a, Trans t) => [a] -> DAWG t a Weight c -> Maybe IntSource

Position in a set of all dictionary entries with respect to the lexicographic order.

byIndex :: (Enum a, Trans t) => Int -> DAWG t a Weight c -> Maybe [a]Source

Find dictionary entry given its index with respect to the lexicographic order.

# Hash

hash :: (Enum a, Trans t) => [a] -> DAWG t a Weight c -> Maybe IntSource

Perfect hashing function for dictionary entries.
A synonym for the `index`

function.

# Construction

fromListWith :: (Enum a, MkNode t b) => (b -> b -> b) -> [([a], b)] -> DAWG t a () bSource

# Weight

Weight of a node corresponds to the number of final states reachable from the node. Weight of an edge is a sum of weights of preceding nodes outgoing from the same parent node.

weigh :: Trans t => DAWG t a b c -> DAWG t a Weight cSource

Compute node weights and store corresponding values in transition labels.

# Conversion

assocs :: (Enum a, Trans t, Unbox b) => DAWG t a b c -> [([a], c)]Source

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