| Safe Haskell | Safe |
|---|---|
| Language | Haskell2010 |
Data.Tuple.Extra
Description
Extra functions for working with pairs and triples. Some of these functions are available in the Control.Arrow module, but here are available specialised to pairs. Some operations work on triples.
- module Data.Tuple
- first :: (a -> a') -> (a, b) -> (a', b)
- second :: (b -> b') -> (a, b) -> (a, b')
- (***) :: (a -> a') -> (b -> b') -> (a, b) -> (a', b')
- (&&&) :: (a -> b) -> (a -> c) -> a -> (b, c)
- dupe :: a -> (a, a)
- both :: (a -> b) -> (a, a) -> (b, b)
- fst3 :: (a, b, c) -> a
- snd3 :: (a, b, c) -> b
- thd3 :: (a, b, c) -> c
Documentation
module Data.Tuple
Specialised Arrow functions
first :: (a -> a') -> (a, b) -> (a', b) Source
Update the first component of a pair.
first succ (1,"test") == (2,"test")
second :: (b -> b') -> (a, b) -> (a, b') Source
Update the second component of a pair.
second reverse (1,"test") == (1,"tset")
(***) :: (a -> a') -> (b -> b') -> (a, b) -> (a', b') infixr 3 Source
Given two functions, apply one to the first component and one to the second.
A specialised version of ***.
(succ *** reverse) (1,"test") == (2,"tset")
(&&&) :: (a -> b) -> (a -> c) -> a -> (b, c) infixr 3 Source
Given two functions, apply both to a single argument to form a pair.
A specialised version of &&&.
(succ &&& pred) 1 == (2,0)
More pair operations
both :: (a -> b) -> (a, a) -> (b, b) Source
Apply a single function to both components of a pair.
both succ (1,2) == (2,3)