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Within LTS Haskell 24.66 (ghc-9.10.3)

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  1. listToMaybe :: [a] -> Maybe a

    base Data.Maybe

    The listToMaybe function returns Nothing on an empty list or Just a where a is the first element of the list.

    Examples

    Basic usage:
    >>> listToMaybe []
    Nothing
    
    >>> listToMaybe [9]
    Just 9
    
    >>> listToMaybe [1,2,3]
    Just 1
    
    Composing maybeToList with listToMaybe should be the identity on singleton/empty lists:
    >>> maybeToList $ listToMaybe [5]
    [5]
    
    >>> maybeToList $ listToMaybe []
    []
    
    But not on lists with more than one element:
    >>> maybeToList $ listToMaybe [1,2,3]
    [1]
    

  2. listToMaybeLast :: [a] -> Maybe a

    test-framework Test.Framework.Providers.API

    No documentation available.

  3. headMay :: [a] -> Maybe a

    safe Safe

    No documentation available.

  4. lastMay :: [a] -> Maybe a

    safe Safe

    No documentation available.

  5. safeHead :: [a] -> Maybe a

    Cabal Distribution.Simple.Utils

    A total variant of head.

  6. safeLast :: [a] -> Maybe a

    Cabal Distribution.Simple.Utils

    A total variant of last.

  7. lastMaybe :: [a] -> Maybe a

    ghc GHC.Utils.Misc

    No documentation available.

  8. listToMaybe :: [a] -> Maybe a

    strict Data.Strict.Maybe

    Analogous to listToMaybe in Data.Maybe.

  9. headMaybe :: [a] -> Maybe a

    rio RIO.List

    No documentation available.

  10. lastMaybe :: [a] -> Maybe a

    rio RIO.List

    No documentation available.

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