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
- null :: m -> Bool
class MonoidNull m => PositiveMonoid m

Documentation

class Monoid m => MonoidNull m where Source #

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.

Methods

null :: m -> Bool Source #

Instances

MonoidNull Ordering Source #
Instance details Defined in Data.Monoid.Null Methods null :: Ordering -> Bool Source #
MonoidNull () Source #
Instance details Defined in Data.Monoid.Null Methods null :: () -> Bool Source #
MonoidNull All Source #
Instance details Defined in Data.Monoid.Null Methods null :: All -> Bool Source #
MonoidNull Any Source #
Instance details Defined in Data.Monoid.Null Methods null :: Any -> Bool Source #
MonoidNull ByteString Source #
Instance details Defined in Data.Monoid.Null Methods null :: ByteString -> Bool Source #
MonoidNull ByteString Source #
Instance details Defined in Data.Monoid.Null Methods null :: ByteString -> Bool Source #
MonoidNull IntSet Source #
Instance details Defined in Data.Monoid.Null Methods null :: IntSet -> Bool Source #
MonoidNull Text Source #
Instance details Defined in Data.Monoid.Null Methods null :: Text -> Bool Source #
MonoidNull Text Source #
Instance details Defined in Data.Monoid.Null Methods null :: Text -> Bool Source #
MonoidNull ByteStringUTF8 Source #	O(1)
Instance details Defined in Data.Monoid.Instances.ByteString.UTF8 Methods null :: ByteStringUTF8 -> Bool Source #
MonoidNull [x] Source #
Instance details Defined in Data.Monoid.Null Methods null :: [x] -> Bool Source #
Monoid a => MonoidNull (Maybe a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Maybe a -> Bool Source #
MonoidNull (First a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: First a -> Bool Source #
MonoidNull (Last a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Last a -> Bool Source #
MonoidNull a => MonoidNull (Dual a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Dual a -> Bool Source #
(Num a, Eq a) => MonoidNull (Sum a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Sum a -> Bool Source #
(Num a, Eq a) => MonoidNull (Product a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Product a -> Bool Source #
MonoidNull (IntMap v) Source #
Instance details Defined in Data.Monoid.Null Methods null :: IntMap v -> Bool Source #
MonoidNull (Seq a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Seq a -> Bool Source #
Ord a => MonoidNull (Set a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Set a -> Bool Source #
MonoidNull (Vector a) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Vector a -> Bool Source #
(StableFactorial m, TextualMonoid m, MonoidNull m) => MonoidNull (LinePositioned m) Source #
Instance details Defined in Data.Monoid.Instances.Positioned Methods null :: LinePositioned m -> Bool Source #
(StableFactorial m, FactorialMonoid m) => MonoidNull (OffsetPositioned m) Source #
Instance details Defined in Data.Monoid.Instances.Positioned Methods null :: OffsetPositioned m -> Bool Source #
(StableFactorial a, Monoid a) => MonoidNull (Measured a) Source #
Instance details Defined in Data.Monoid.Instances.Measured Methods null :: Measured a -> Bool Source #
PositiveMonoid a => MonoidNull (Concat a) Source #
Instance details Defined in Data.Monoid.Instances.Concat Methods null :: Concat a -> Bool Source #
(MonoidNull a, MonoidNull b) => MonoidNull (a, b) Source #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b) -> Bool Source #
Ord k => MonoidNull (Map k v) Source #
Instance details Defined in Data.Monoid.Null Methods null :: Map k v -> Bool Source #
(MonoidNull a, MonoidNull b) => MonoidNull (Stateful a b) Source #
Instance details Defined in Data.Monoid.Instances.Stateful Methods null :: Stateful a b -> Bool Source #
(MonoidNull a, MonoidNull b, MonoidNull c) => MonoidNull (a, b, c) Source #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b, c) -> Bool Source #
(MonoidNull a, MonoidNull b, MonoidNull c, MonoidNull d) => MonoidNull (a, b, c, d) Source #
Instance details Defined in Data.Monoid.Null Methods null :: (a, b, c, d) -> Bool Source #

class MonoidNull m => PositiveMonoid m Source #

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