Modulerelude-1.2.2.2Haskell2010

Relude.Extra.Enum

SPDX-License-Identifier : MIT Maintainer : Kowainik xrom.xkov@gmail.com Stability : Stable Portability : Portable

Mini bounded-enum framework inside relude.

valuenext :: (Eq a, Bounded a, Enum a) => a -> a

Like succ, but doesn't fail on maxBound. Instead it returns minBound.

Example3 expressions

>>> next FalseTrue>>> next TrueFalse>>> succ True*** Exception: Prelude.Enum.Bool.succ: bad argument

valueprev :: (Eq a, Bounded a, Enum a) => a -> a

Like pred, but doesn't fail on minBound. Instead it returns maxBound.

Example3 expressions

>>> prev TrueFalse>>> prev FalseTrue>>> pred False*** Exception: Prelude.Enum.Bool.pred: bad argument

valuesafeToEnum :: (Bounded a, Enum a) => Int -> Maybe a

Returns Nothing if given Int outside range.

Example4 expressions

>>> safeToEnum @Bool 0Just False>>> safeToEnum @Bool 1Just True>>> safeToEnum @Bool 2Nothing>>> safeToEnum @Bool (-1)Nothing