Safe Haskell	Trustworthy
Language	Haskell2010

Data.Monoid.Null

Description

This module defines the MonoidNull class and some of its instances.

Synopsis

class Monoid m => MonoidNull m where
class MonoidNull m => PositiveMonoid m

Documentation

class Monoid m => MonoidNull m where #

Extension of Monoid that allows testing a value for equality with mempty. The following law must hold:

null x == (x == mempty)

Furthermore, the performance of this method should be constant, i.e., independent of the length of its argument.

Minimal complete definition

null

Methods

null :: m -> Bool #

Instances

MonoidNull Ordering #
Instance details Defined in Data.Monoid.Null Methods null :: Ordering -> Bool #
MonoidNull () #
Instance details Defined in Data.Monoid.Null Methods null :: () -> Bool #
MonoidNull All #
Instance details Defined in Data.Monoid.Null Methods null :: All -> Bool #
MonoidNull Any #
Instance details Defined in Data.Monoid.Null Methods null :: Any -> Bool #
MonoidNull ByteString #
Instance details Defined in Data.Monoid.Null Methods null :: ByteString -> Bool #
MonoidNull ByteString #
Instance details Defined in Data.Monoid.Null Methods null :: ByteString -> Bool #
MonoidNull IntSet #
Instance details Defined in Data.Monoid.Null Methods null :: IntSet -> Bool #
MonoidNull Text #
Instance details Defined in Data.Monoid.Null Methods null :: Text -> Bool #
MonoidNull Text #
Instance details Defined in Data.Monoid.Null Methods null :: Text -> Bool #
MonoidNull ByteStringUTF8 #
Instance details Defined in Data.Monoid.Instances.ByteString.UTF8 Methods null :: ByteStringUTF8 -> Bool #
MonoidNull [x] #
Instance details Defined in Data.Monoid.Null Methods null :: [x] -> Bool #
Monoid a => MonoidNull (Maybe a) #
Instance details Defined in Data.Monoid.Null Methods null :: Maybe a -> Bool #
MonoidNull (First a) #
Instance details Defined in Data.Monoid.Null Methods null :: First a -> Bool #
MonoidNull (Last a) #
Instance details Defined in Data.Monoid.Null Methods null :: Last a -> Bool #
MonoidNull a => MonoidNull (Dual a) #
Instance details Defined in Data.Monoid.Null Methods null :: Dual a -> Bool #
(Num a, Eq a) => MonoidNull (Sum a) #
Instance details Defined in Data.Monoid.Null Methods null :: Sum a -> Bool #
(Num a, Eq a) => MonoidNull (Product a) #
Instance details Defined in Data.Monoid.Null Methods null :: Product a -> Bool #
MonoidNull (IntMap v) #
Instance details Defined in Data.Monoid.Null Methods null :: IntMap v -> Bool #
MonoidNull (Seq a) #
Instance details Defined in Data.Monoid.Null Methods null :: Seq a -> Bool #
Ord a => MonoidNull (Set a) #
Instance details Defined in Data.Monoid.Null Methods null :: Set a -> Bool #
MonoidNull (Vector a) #
Instance details Defined in Data.Monoid.Null Methods null :: Vector a -> Bool #
(StableFactorialMonoid m, TextualMonoid m, MonoidNull m) => MonoidNull (LinePositioned m) #
Instance details Defined in Data.Monoid.Instances.Positioned Methods null :: LinePositioned m -> Bool #
(StableFactorialMonoid m, MonoidNull m) => MonoidNull (OffsetPositioned m) #
Instance details Defined in Data.Monoid.Instances.Positioned Methods null :: OffsetPositioned m -> Bool #
StableFactorialMonoid a => MonoidNull (Measured a) #
Instance details Defined in Data.Monoid.Instances.Measured Methods null :: Measured a -> Bool #
PositiveMonoid a => MonoidNull (Concat a) #
Instance details Defined in Data.Monoid.Instances.Concat Methods null :: Concat a -> Bool #
(MonoidNull a, MonoidNull b) => MonoidNull (a, b) #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b) -> Bool #
Ord k => MonoidNull (Map k v) #
Instance details Defined in Data.Monoid.Null Methods null :: Map k v -> Bool #
(MonoidNull a, MonoidNull b) => MonoidNull (Stateful a b) #
Instance details Defined in Data.Monoid.Instances.Stateful Methods null :: Stateful a b -> Bool #
(MonoidNull a, MonoidNull b, MonoidNull c) => MonoidNull (a, b, c) #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b, c) -> Bool #
(MonoidNull a, MonoidNull b, MonoidNull c, MonoidNull d) => MonoidNull (a, b, c, d) #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b, c, d) -> Bool #

class MonoidNull m => PositiveMonoid m #

Subclass of Monoid for types whose values have no inverse, with the exception of mempty. More formally, the class instances must satisfy the following law:

null (x <> y) == (null x && null y)

Instances

PositiveMonoid Ordering #
Instance details Defined in Data.Monoid.Null
PositiveMonoid () #
Instance details Defined in Data.Monoid.Null
PositiveMonoid All #
Instance details Defined in Data.Monoid.Null
PositiveMonoid Any #
Instance details Defined in Data.Monoid.Null
PositiveMonoid ByteString #
Instance details Defined in Data.Monoid.Null
PositiveMonoid ByteString #
Instance details Defined in Data.Monoid.Null
PositiveMonoid IntSet #
Instance details Defined in Data.Monoid.Null
PositiveMonoid Text #
Instance details Defined in Data.Monoid.Null
PositiveMonoid Text #
Instance details Defined in Data.Monoid.Null
PositiveMonoid ByteStringUTF8 #
Instance details Defined in Data.Monoid.Instances.ByteString.UTF8
PositiveMonoid [x] #
Instance details Defined in Data.Monoid.Null
Monoid a => PositiveMonoid (Maybe a) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid (First a) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid (Last a) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid a => PositiveMonoid (Dual a) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid (IntMap v) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid (Seq a) #
Instance details Defined in Data.Monoid.Null
Ord a => PositiveMonoid (Set a) #
Instance details Defined in Data.Monoid.Null
PositiveMonoid (Vector a) #
Instance details Defined in Data.Monoid.Null
(StableFactorialMonoid m, TextualMonoid m) => PositiveMonoid (LinePositioned m) #
Instance details Defined in Data.Monoid.Instances.Positioned
StableFactorialMonoid m => PositiveMonoid (OffsetPositioned m) #
Instance details Defined in Data.Monoid.Instances.Positioned
StableFactorialMonoid a => PositiveMonoid (Measured a) #
Instance details Defined in Data.Monoid.Instances.Measured
PositiveMonoid a => PositiveMonoid (Concat a) #
Instance details Defined in Data.Monoid.Instances.Concat
Ord k => PositiveMonoid (Map k v) #
Instance details Defined in Data.Monoid.Null
(PositiveMonoid a, PositiveMonoid b) => PositiveMonoid (Stateful a b) #
Instance details Defined in Data.Monoid.Instances.Stateful