Data.Ord

base-4.3.1.0: Basic libraries

Portability | portable
Stability | stable
Maintainer | libraries@haskell.org

Data.Ord

Description

Orderings

Synopsis

- class Eq a => Ord a where
  - compare :: a -> a -> Ordering
  - (<) :: a -> a -> Bool
  - (>=) :: a -> a -> Bool
  - (>) :: a -> a -> Bool
  - (<=) :: a -> a -> Bool
  - max :: a -> a -> a
  - min :: a -> a -> a
- data Ordering
  - = LT
  - | EQ
  - | GT
- comparing :: Ord a => (b -> a) -> b -> b -> Ordering

# Documentation

class Eq a => Ord a where

The `Ord` class is used for totally ordered datatypes.

Instances of `Ord` can be derived for any user-defined datatype whose constituent types are in `Ord`. The declared order of the constructors in the data declaration determines the ordering in derived `Ord` instances. The `Ordering` datatype allows a single comparison to determine the precise ordering of two objects.

Minimal complete definition: either `compare` or `<=`. Using `compare` can be more efficient for complex types.

Methods

compare :: a -> a -> Ordering

(<) :: a -> a -> Bool

(>=) :: a -> a -> Bool

(>) :: a -> a -> Bool

(<=) :: a -> a -> Bool

max :: a -> a -> a

min :: a -> a -> a

Instances

Ord Bool |
Ord Char |
Ord Double |
Ord Float |
Ord Int |
Ord Int8 |
Ord Int16 |
Ord Int32 |
Ord Int64 |
Ord Integer |
Ord Ordering |
Ord Word |
Ord Word8 |
Ord Word16 |
Ord Word32 |
Ord Word64 |
Ord () |
Ord ArithException |
Ord IOMode |
Ord SeekMode |
Ord CUIntMax |
Ord CIntMax |
Ord CUIntPtr |
Ord CIntPtr |
Ord CTime |
Ord CClock |
Ord CSigAtomic |
Ord CWchar |
Ord CSize |
Ord CPtrdiff |
Ord CDouble |
Ord CFloat |
Ord CULLong |
Ord CLLong |
Ord CULong |
Ord CLong |
Ord CUInt |
Ord CInt |
Ord CUShort |
Ord CShort |
Ord CUChar |
Ord CSChar |
Ord CChar |
Ord Any |
Ord All |
Ord GeneralCategory |
Ord IntPtr |
Ord WordPtr |
Ord NewlineMode |
Ord Newline |
Ord BufferMode |
Ord ExitCode |
Ord ArrayException |
Ord AsyncException |
Ord ThreadStatus |
Ord BlockReason |
Ord ThreadId |
Ord Fd |
Ord CRLim |
Ord CTcflag |
Ord CSpeed |
Ord CCc |
Ord CUid |
Ord CNlink |
Ord CGid |
Ord CSsize |
Ord CPid |
Ord COff |
Ord CMode |
Ord CIno |
Ord CDev |
Ord Unique |
Ord Unique |
Ord Version |
Ord a => Ord [a] |
Integral a => Ord (Ratio a) |
Ord (Ptr a) |
Ord (FunPtr a) |
Ord a => Ord ([::] a) |
Ord a => Ord (Maybe a) |
Ord a => Ord (Last a) |
Ord a => Ord (First a) |
Ord a => Ord (Product a) |
Ord a => Ord (Sum a) |
Ord a => Ord (Dual a) |
Ord (ForeignPtr a) |
Ord a => Ord (Down a) |
Ord (Fixed a) |
(Ord a, Ord b) => Ord (Either a b) |
(Ord a, Ord b) => Ord (a, b) |
(Ix i, Ord e) => Ord (Array i e) |
(Ord a, Ord b, Ord c) => Ord (a, b, c) |
(Ord a, Ord b, Ord c, Ord d) => Ord (a, b, c, d) |
(Ord a, Ord b, Ord c, Ord d, Ord e) => Ord (a, b, c, d, e) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f) => Ord (a, b, c, d, e, f) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g) => Ord (a, b, c, d, e, f, g) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h) => Ord (a, b, c, d, e, f, g, h) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i) => Ord (a, b, c, d, e, f, g, h, i) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j) => Ord (a, b, c, d, e, f, g, h, i, j) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k) => Ord (a, b, c, d, e, f, g, h, i, j, k) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l) => Ord (a, b, c, d, e, f, g, h, i, j, k, l) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n) |
(Ord a, Ord b, Ord c, Ord d, Ord e, Ord f, Ord g, Ord h, Ord i, Ord j, Ord k, Ord l, Ord m, Ord n, Ord o) => Ord (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) |

data Ordering Source

Constructors

LT |
EQ |
GT |

Instances

Bounded Ordering |
Enum Ordering |
Eq Ordering |
Data Ordering |
Ord Ordering |
Read Ordering |
Show Ordering |
Ix Ordering |
Typeable Ordering |
Monoid Ordering |

comparing :: Ord a => (b -> a) -> b -> b -> Ordering

     comparing p x y = compare (p x) (p y)

Useful combinator for use in conjunction with the `xxxBy` family of functions from Data.List, for example:

       ... sortBy (comparing fst) ...