Unbound.Generics.LocallyNameless.LFresh

Local freshness monad.

The LFresh class

class Monad m => LFresh m where

This is the class of monads that support freshness in an (implicit) local scope. Generated names are fresh for the current local scope, not necessarily globally fresh.

Methods

lfresh :: Typeable a => Name a -> m (Name a)

Pick a new name that is fresh for the current (implicit) scope.

avoid :: [AnyName] -> m a -> m a

Avoid the given names when freshening in the subcomputation, that is, add the given names to the in-scope set.

getAvoids :: m (Set AnyName)

Get the set of names currently being avoided.

Instances

LFresh m => LFresh (IdentityT m)

LFresh m => LFresh (ListT m)

LFresh m => LFresh (MaybeT m)

Monad m => LFresh (LFreshMT m)

LFresh m => LFresh (ContT r m)

LFresh m => LFresh (ReaderT r m)

LFresh m => LFresh (StateT s m)

LFresh m => LFresh (StateT s m)

LFresh m => LFresh (ExceptT e m)

(Error e, LFresh m) => LFresh (ErrorT e m)

(Monoid w, LFresh m) => LFresh (WriterT w m)

(Monoid w, LFresh m) => LFresh (WriterT w m)

type LFreshM = LFreshMT Identity

A convenient monad which is an instance of LFresh. It keeps track of a set of names to avoid, and when asked for a fresh one will choose the first unused numerical name.

runLFreshM :: LFreshM a -> a

Run a LFreshM computation in an empty context.

contLFreshM :: LFreshM a -> Set AnyName -> a

Run a LFreshM computation given a set of names to avoid.

newtype LFreshMT m a

The LFresh monad transformer. Keeps track of a set of names to avoid, and when asked for a fresh one will choose the first numeric prefix of the given name which is currently unused.

Constructors

LFreshMT

Fields

unLFreshMT :: ReaderT (Set AnyName) m a

Instances

MonadTrans LFreshMT

MonadError e m => MonadError e (LFreshMT m)

MonadReader r m => MonadReader r (LFreshMT m)

MonadState s m => MonadState s (LFreshMT m)

MonadWriter w m => MonadWriter w (LFreshMT m)

Alternative m => Alternative (LFreshMT m)

Monad m => Monad (LFreshMT m)

Functor m => Functor (LFreshMT m)

MonadFix m => MonadFix (LFreshMT m)

MonadPlus m => MonadPlus (LFreshMT m)

Applicative m => Applicative (LFreshMT m)

MonadIO m => MonadIO (LFreshMT m)

MonadCont m => MonadCont (LFreshMT m)

Monad m => LFresh (LFreshMT m)

runLFreshMT :: LFreshMT m a -> m a

Run an LFreshMT computation in an empty context.

contLFreshMT :: LFreshMT m a -> Set AnyName -> m a

Run an LFreshMT computation given a set of names to avoid.