| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
RIO.Partial
Description
Partial functions. Import as:
import qualified RIO.Partial as RIO'
Documentation
fromJust :: HasCallStack => Maybe a -> a #
The fromJust function extracts the element out of a Just and
throws an error if its argument is Nothing.
Examples
Basic usage:
>>>fromJust (Just 1)1
>>>2 * (fromJust (Just 10))20
>>>2 * (fromJust Nothing)*** Exception: Maybe.fromJust: Nothing ...
WARNING: This function is partial. You can use case-matching instead.
read :: Read a => String -> a #
The read function reads input from a string, which must be
completely consumed by the input process. read fails with an error if the
parse is unsuccessful, and it is therefore discouraged from being used in
real applications. Use readMaybe or readEither for safe alternatives.
>>>read "123" :: Int123
>>>read "hello" :: Int*** Exception: Prelude.read: no parse