Copyright	Copyright (c) 2007--2021 wren gayle romano
License	BSD3
Maintainer	wren@cpan.org
Stability	stable
Portability	semi-portable (OverlappingInstances,...)
Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.Number.PartialOrd

Contents

Description

The Prelude's Ord class for dealing with ordered types is often onerous to use because it requires Eq as well as a total ordering. While such total orderings are common, partial orderings are more so. This module presents a class for partially ordered types.

Synopsis

class PartialOrd a where
- cmp :: a -> a -> Maybe Ordering
- gt :: a -> a -> Maybe Bool
- ge :: a -> a -> Maybe Bool
- eq :: a -> a -> Maybe Bool
- ne :: a -> a -> Maybe Bool
- le :: a -> a -> Maybe Bool
- lt :: a -> a -> Maybe Bool
- maxPO :: a -> a -> Maybe a
- minPO :: a -> a -> Maybe a
comparingPO :: PartialOrd b => (a -> b) -> a -> a -> Maybe Ordering

Partial Ordering

class PartialOrd a where Source #

This class defines a partially ordered type. The method names were chosen so as not to conflict with Ord and Eq. We use Maybe instead of defining new types PartialOrdering and FuzzyBool because this way should make the class easier to use.

Minimum complete definition: cmp

Minimal complete definition

cmp

Methods

cmp :: a -> a -> Maybe Ordering Source #

like compare

gt :: a -> a -> Maybe Bool infix 4 Source #

like (>)

ge :: a -> a -> Maybe Bool infix 4 Source #

like (>=)

eq :: a -> a -> Maybe Bool infix 4 Source #

like (==)

ne :: a -> a -> Maybe Bool infix 4 Source #

like (/=)

le :: a -> a -> Maybe Bool infix 4 Source #

like (<=)

lt :: a -> a -> Maybe Bool infix 4 Source #

like (<)

maxPO :: a -> a -> Maybe a infix 4 Source #

like max. The default instance returns the left argument when they're equal.

minPO :: a -> a -> Maybe a infix 4 Source #

like min. The default instance returns the left argument when they're equal.

Instances

Instances details

PartialOrd LogFloat Source #
Instance details Defined in Data.Number.LogFloat Methods cmp :: LogFloat -> LogFloat -> Maybe Ordering Source # gt :: LogFloat -> LogFloat -> Maybe Bool Source # ge :: LogFloat -> LogFloat -> Maybe Bool Source # eq :: LogFloat -> LogFloat -> Maybe Bool Source # ne :: LogFloat -> LogFloat -> Maybe Bool Source # le :: LogFloat -> LogFloat -> Maybe Bool Source # lt :: LogFloat -> LogFloat -> Maybe Bool Source # maxPO :: LogFloat -> LogFloat -> Maybe LogFloat Source # minPO :: LogFloat -> LogFloat -> Maybe LogFloat Source #
PartialOrd Double Source #
Instance details Defined in Data.Number.PartialOrd Methods cmp :: Double -> Double -> Maybe Ordering Source # gt :: Double -> Double -> Maybe Bool Source # ge :: Double -> Double -> Maybe Bool Source # eq :: Double -> Double -> Maybe Bool Source # ne :: Double -> Double -> Maybe Bool Source # le :: Double -> Double -> Maybe Bool Source # lt :: Double -> Double -> Maybe Bool Source # maxPO :: Double -> Double -> Maybe Double Source # minPO :: Double -> Double -> Maybe Double Source #
PartialOrd Float Source #
Instance details Defined in Data.Number.PartialOrd Methods cmp :: Float -> Float -> Maybe Ordering Source # gt :: Float -> Float -> Maybe Bool Source # ge :: Float -> Float -> Maybe Bool Source # eq :: Float -> Float -> Maybe Bool Source # ne :: Float -> Float -> Maybe Bool Source # le :: Float -> Float -> Maybe Bool Source # lt :: Float -> Float -> Maybe Bool Source # maxPO :: Float -> Float -> Maybe Float Source # minPO :: Float -> Float -> Maybe Float Source #
Ord a => PartialOrd a Source #
Instance details Defined in Data.Number.PartialOrd Methods cmp :: a -> a -> Maybe Ordering Source # gt :: a -> a -> Maybe Bool Source # ge :: a -> a -> Maybe Bool Source # eq :: a -> a -> Maybe Bool Source # ne :: a -> a -> Maybe Bool Source # le :: a -> a -> Maybe Bool Source # lt :: a -> a -> Maybe Bool Source # maxPO :: a -> a -> Maybe a Source # minPO :: a -> a -> Maybe a Source #

Functions

comparingPO :: PartialOrd b => (a -> b) -> a -> a -> Maybe Ordering Source #

Like Data.Ord.comparing. Helpful in conjunction with the xxxBy family of functions from Data.List