Safe Haskell	None
Language	Haskell2010

Data.HashCons.Internal

Synopsis

data HashCons a = HashConsC {
- _hashCons_hash :: !Int
- _hashCons_ref :: !(IORef a)
}
pattern HashCons :: Hashable a => a -> HashCons a
hashCons :: Hashable a => a -> HashCons a
unHashCons :: HashCons a -> a
compareAndSubstitute :: Eq r => (a -> a -> r) -> r -> IORef a -> IORef a -> r

Documentation

data HashCons a Source #

HashCons with a precomputed hash and an IORef to the value.

WARNING: Do not use this type to wrap types whose Eq or Ord instances allow distinguishable values to compare as equal; this will result in nondeterminism or even visible mutation of semantically-immutable values at runtime.

Constructors

HashConsC
Fields _hashCons_hash :: !Int Precomputed hash _hashCons_ref :: !(IORef a) Reference to the value

Instances

Instances details

(Read a, Hashable a) => Read (HashCons a) Source #	Read instance that parses `HashCons` from the format "hashCons x"
Instance details Defined in Data.HashCons.Internal Methods readsPrec :: Int -> ReadS (HashCons a) # readList :: ReadS [HashCons a] # readPrec :: ReadPrec (HashCons a) # readListPrec :: ReadPrec [HashCons a] #
Show a => Show (HashCons a) Source #	Show instance that displays `HashCons` in the format "hashCons x"
Instance details Defined in Data.HashCons.Internal Methods showsPrec :: Int -> HashCons a -> ShowS # show :: HashCons a -> String # showList :: [HashCons a] -> ShowS #
Eq a => Eq (HashCons a) Source #
Instance details Defined in Data.HashCons.Internal Methods (==) :: HashCons a -> HashCons a -> Bool # (/=) :: HashCons a -> HashCons a -> Bool #
Ord a => Ord (HashCons a) Source #	NOTE: This instance orders by hash first, and only secondarily by the `Ord` instance of `a`, to improve performance.
Instance details Defined in Data.HashCons.Internal Methods compare :: HashCons a -> HashCons a -> Ordering # (<) :: HashCons a -> HashCons a -> Bool # (<=) :: HashCons a -> HashCons a -> Bool # (>) :: HashCons a -> HashCons a -> Bool # (>=) :: HashCons a -> HashCons a -> Bool # max :: HashCons a -> HashCons a -> HashCons a # min :: HashCons a -> HashCons a -> HashCons a #
Eq a => Hashable (HashCons a) Source #
Instance details Defined in Data.HashCons.Internal Methods hashWithSalt :: Int -> HashCons a -> Int # hash :: HashCons a -> Int #

pattern HashCons :: Hashable a => a -> HashCons a Source #

hashCons :: Hashable a => a -> HashCons a Source #

Create a new HashCons.

unHashCons :: HashCons a -> a Source #

Extract the value from a HashCons.

compareAndSubstitute :: Eq r => (a -> a -> r) -> r -> IORef a -> IORef a -> r Source #