| Safe Haskell | Safe |
|---|---|
| Language | Haskell2010 |
Safe
Contents
Description
A module wrapping Prelude/Data.List functions that can throw exceptions, such as head and !!.
Each unsafe function has up to four variants, e.g. with tail:
tail:: [a] -> [a]tail [].tailMay:: [a] -> Maybe [a]Nothing.tailDef:: [a] -> [a] -> [a]tailNote::Partial=> String -> [a] -> [a]tailSafe:: [a] -> [a][]in the case oftail.
All functions marked with the Partial
This module also introduces some new functions, documented at the top of the module.
- abort :: Partial => String -> a
- at :: Partial => [a] -> Int -> a
- lookupJust :: Eq a => a -> [(a, b)] -> b
- findJust :: (a -> Bool) -> [a] -> a
- elemIndexJust :: Eq a => a -> [a] -> Int
- findIndexJust :: (a -> Bool) -> [a] -> Int
- tailMay :: [a] -> Maybe [a]
- tailDef :: [a] -> [a] -> [a]
- tailNote :: Partial => String -> [a] -> [a]
- tailSafe :: [a] -> [a]
- initMay :: [a] -> Maybe [a]
- initDef :: [a] -> [a] -> [a]
- initNote :: Partial => String -> [a] -> [a]
- initSafe :: [a] -> [a]
- headMay :: [a] -> Maybe a
- headDef :: a -> [a] -> a
- headNote :: String -> [a] -> a
- lastMay :: [a] -> Maybe a
- lastDef :: a -> [a] -> a
- lastNote :: String -> [a] -> a
- minimumMay :: Ord a => [a] -> Maybe a
- minimumDef :: Ord a => a -> [a] -> a
- minimumNote :: (Partial, Ord a) => String -> [a] -> a
- maximumMay :: Ord a => [a] -> Maybe a
- maximumDef :: Ord a => a -> [a] -> a
- maximumNote :: (Partial, Ord a) => String -> [a] -> a
- minimumByMay :: (a -> a -> Ordering) -> [a] -> Maybe a
- minimumByDef :: a -> (a -> a -> Ordering) -> [a] -> a
- minimumByNote :: Partial => String -> (a -> a -> Ordering) -> [a] -> a
- maximumByMay :: (a -> a -> Ordering) -> [a] -> Maybe a
- maximumByDef :: a -> (a -> a -> Ordering) -> [a] -> a
- maximumByNote :: Partial => String -> (a -> a -> Ordering) -> [a] -> a
- foldr1May :: (a -> a -> a) -> [a] -> Maybe a
- foldr1Def :: a -> (a -> a -> a) -> [a] -> a
- foldr1Note :: Partial => String -> (a -> a -> a) -> [a] -> a
- foldl1May :: (a -> a -> a) -> [a] -> Maybe a
- foldl1Def :: a -> (a -> a -> a) -> [a] -> a
- foldl1Note :: Partial => String -> (a -> a -> a) -> [a] -> a
- foldl1May' :: (a -> a -> a) -> [a] -> Maybe a
- foldl1Def' :: a -> (a -> a -> a) -> [a] -> a
- foldl1Note' :: Partial => String -> (a -> a -> a) -> [a] -> a
- scanl1May :: (a -> a -> a) -> [a] -> Maybe [a]
- scanl1Def :: [a] -> (a -> a -> a) -> [a] -> [a]
- scanl1Note :: Partial => String -> (a -> a -> a) -> [a] -> [a]
- scanr1May :: (a -> a -> a) -> [a] -> Maybe [a]
- scanr1Def :: [a] -> (a -> a -> a) -> [a] -> [a]
- scanr1Note :: Partial => String -> (a -> a -> a) -> [a] -> [a]
- cycleMay :: [a] -> Maybe [a]
- cycleDef :: [a] -> [a] -> [a]
- cycleNote :: Partial => String -> [a] -> [a]
- fromJustDef :: a -> Maybe a -> a
- fromJustNote :: Partial => String -> Maybe a -> a
- assertNote :: Partial => String -> Bool -> a -> a
- atMay :: [a] -> Int -> Maybe a
- atDef :: a -> [a] -> Int -> a
- atNote :: Partial => String -> [a] -> Int -> a
- readMay :: Read a => String -> Maybe a
- readDef :: Read a => a -> String -> a
- readNote :: (Partial, Read a) => String -> String -> a
- readEitherSafe :: Read a => String -> Either String a
- lookupJustDef :: Eq a => b -> a -> [(a, b)] -> b
- lookupJustNote :: (Partial, Eq a) => String -> a -> [(a, b)] -> b
- findJustDef :: a -> (a -> Bool) -> [a] -> a
- findJustNote :: Partial => String -> (a -> Bool) -> [a] -> a
- elemIndexJustDef :: Eq a => Int -> a -> [a] -> Int
- elemIndexJustNote :: (Partial, Eq a) => String -> a -> [a] -> Int
- findIndexJustDef :: Int -> (a -> Bool) -> [a] -> Int
- findIndexJustNote :: Partial => String -> (a -> Bool) -> [a] -> Int
- toEnumMay :: (Enum a, Bounded a) => Int -> Maybe a
- toEnumDef :: (Enum a, Bounded a) => a -> Int -> a
- toEnumNote :: (Partial, Enum a, Bounded a) => String -> Int -> a
- toEnumSafe :: (Enum a, Bounded a) => Int -> a
- succMay :: (Enum a, Eq a, Bounded a) => a -> Maybe a
- succDef :: (Enum a, Eq a, Bounded a) => a -> a -> a
- succNote :: (Partial, Enum a, Eq a, Bounded a) => String -> a -> a
- succSafe :: (Enum a, Eq a, Bounded a) => a -> a
- predMay :: (Enum a, Eq a, Bounded a) => a -> Maybe a
- predDef :: (Enum a, Eq a, Bounded a) => a -> a -> a
- predNote :: (Partial, Enum a, Eq a, Bounded a) => String -> a -> a
- predSafe :: (Enum a, Eq a, Bounded a) => a -> a
New functions
at :: Partial => [a] -> Int -> a Source #
Synonym for !!, but includes more information in the error message.
lookupJust :: Eq a => a -> [(a, b)] -> b Source #
lookupJust key = fromJust . lookup key
elemIndexJust :: Eq a => a -> [a] -> Int Source #
elemIndexJust op = fromJust . elemIndex op
findIndexJust :: (a -> Bool) -> [a] -> Int Source #
findIndexJust op = fromJust . findIndex op
Safe wrappers
tailNote :: Partial => String -> [a] -> [a] Source #
tailNote "help me" [] = error "Safe.tailNote [], help me" tailNote "help me" [1,3,4] = [3,4]
minimumMay :: Ord a => [a] -> Maybe a Source #
minimumDef :: Ord a => a -> [a] -> a Source #
maximumMay :: Ord a => [a] -> Maybe a Source #
maximumDef :: Ord a => a -> [a] -> a Source #
minimumByMay :: (a -> a -> Ordering) -> [a] -> Maybe a Source #
minimumByDef :: a -> (a -> a -> Ordering) -> [a] -> a Source #
maximumByMay :: (a -> a -> Ordering) -> [a] -> Maybe a Source #
maximumByDef :: a -> (a -> a -> Ordering) -> [a] -> a Source #
foldr1Note :: Partial => String -> (a -> a -> a) -> [a] -> a Source #
foldl1Note :: Partial => String -> (a -> a -> a) -> [a] -> a Source #
foldl1May' :: (a -> a -> a) -> [a] -> Maybe a Source #
foldl1Def' :: a -> (a -> a -> a) -> [a] -> a Source #
foldl1Note' :: Partial => String -> (a -> a -> a) -> [a] -> a Source #
scanl1Note :: Partial => String -> (a -> a -> a) -> [a] -> [a] Source #
scanr1Note :: Partial => String -> (a -> a -> a) -> [a] -> [a] Source #
fromJustDef :: a -> Maybe a -> a Source #
readNote :: (Partial, Read a) => String -> String -> a Source #
readNote uses readEitherSafe for the error message.
readEitherSafe :: Read a => String -> Either String a Source #
This function provides a more precise error message than readEither from base.
lookupJustDef :: Eq a => b -> a -> [(a, b)] -> b Source #
findJustDef :: a -> (a -> Bool) -> [a] -> a Source #