Copyright	(c) 2016 Stephen Diehl (c) 2016-2018 Serokell (c) 2018-2022 Kowainik
License	MIT
Maintainer	Kowainik <xrom.xkov@gmail.com>
Stability	Stable
Portability	Portable
Safe Haskell	Unsafe
Language	Haskell2010

Relude.Unsafe

Contents

Description

⚠️ Warning ⚠️

This module contains unsafe partial functions. They are unavoidable sometimes, but we encourage you to use safer analogues:

Partial	Total
`head :: [a] -> a`	`head :: NonEmpty a -> a`
`tail :: [a] -> [a]`	`tail :: NonEmpty a -> [a]`
`read :: Read a => String -> a`	`readMaybe :: Read a => String -> Maybe a`
`fromJust :: Maybe a -> a`	`fromMaybe :: a -> Maybe a -> a`

This module is intended to be imported qualified and it is not included in default prelude exports.

import qualified Relude.Unsafe as Unsafe

foo :: [a] -> a
foo = Unsafe.head

Synopsis

Unsafe list functions

head :: [a] -> a #

tail :: [a] -> [a] #

last :: [a] -> a #

init :: [a] -> [a] #

(!!) :: [a] -> Int -> a #

at :: Int -> [a] -> a Source #

Similar to !! but with flipped arguments. get element from list using index value starting from `0`.

>>> at 2 ["a", "b", "c"]
"c"

it is also useful when used in a partially applied position like:

>>> map (at 1) [["a","b","c"], ["a","b","c"], ["a","b","c"]]
["b","b","b"]

Unsafe `Maybe` functions

read :: Read a => String -> a #