Data.Equivalence.Monad

This is an alternative interface to the union-find implementation in ''Data.Equivalence.STT''. It is wrapped into the monad transformer EquivT.

Documentation

class (Monad m, Ord v) => MonadEquiv c v m | m -> v, m -> c where

This class specifies the interface for a monadic computation that maintains an equivalence relation.

Methods

equivalent :: v -> v -> m Bool

This function decides whether the two given elements are equivalent in the current equivalence relation

classDesc :: v -> m c

This function obtains the descriptor of the given element's equivalence class.

equate :: v -> v -> m ()

This function equates the given two elements. That is it unions the equivalence classes of the two elements.

Instances

MonadEquiv c v m => MonadEquiv c v (ReaderT r m)

MonadEquiv c v m => MonadEquiv c v (StateT s m)

(MonadEquiv c v m, Error e) => MonadEquiv c v (ErrorT e m)

(MonadEquiv c v m, Monoid w) => MonadEquiv c v (WriterT w m)

(Monad m, Ord v) => MonadEquiv c v (EquivT s c v m)

newtype EquivT s c v m a

This monad transformer encapsulates computations maintaining an equivalence relation. A monadic computation of type EquivT s c v m a maintains a state space indexed by type s, maintains an equivalence relation over elements of type v with equivalence class descriptors of type c and contains an internal monadic computation of type m a.

Constructors

EquivT

Fields

unEquivT :: ReaderT (Equiv s c v) (STT s m) a

Instances

(Monad m, Ord v) => MonadEquiv c v (EquivT s c v m)

MonadReader r m => MonadReader r (EquivT s c v m)

MonadState st m => MonadState st (EquivT s c v m)

MonadError e m => MonadError e (EquivT s c v m)

(Monoid w, MonadWriter w m) => MonadWriter w (EquivT s c v m)

MonadTrans (EquivT s c v)

Monad m => Monad (EquivT s c v m)

type EquivM s c v = EquivT s c v Identity

This monad encapsulates computations maintaining an equivalence relation. A monadic computation of type EquivM s c v a maintains a state space indexed by type s, maintains an equivalence relation over elements of type v with equivalence class descriptors of type c and returns a value of type a.

runEquivT

Arguments

:: Monad m

=> (v -> c)

used to construct an equivalence class descriptor for a singleton class

-> (c -> c -> c)

used to combine the equivalence class descriptor of two classes which are meant to be combined.

-> (forall s. EquivT s c v m a)

-> m a

This function runs a monadic computation that maintains an equivalence relation. The first tow arguments specify how to construct an equivalence class descriptor for a singleton class and how to combine two equivalence class descriptors.

runEquivM

Arguments

:: (v -> c)

used to construct an equivalence class descriptor for a singleton class

-> (c -> c -> c)

used to combine the equivalence class descriptor of two classes which are meant to be combined.

-> (forall s. EquivM s c v a)

-> a

This function runs a monadic computation that maintains an equivalence relation. The first tow arguments specify how to construct an equivalence class descriptor for a singleton class and how to combine two equivalence class descriptors.