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Within LTS Haskell 24.2 (ghc-9.10.2)

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Exact lookup

1. head :: HasCallStack => ShortByteString -> Word8

   bytestring	Data.ByteString.Short.Internal

   O(1) Extract the first element of a ShortByteString, which must be non-empty. An exception will be thrown in the case of an empty ShortByteString. This is a partial function, consider using uncons instead.

2. head :: HasCallStack => Text -> Char

   text	Data.Text

   O(1) Returns the first character of a Text, which must be non-empty. This is a partial function, consider using uncons instead.

3. head :: HasCallStack => Stream Char -> Char

   text	Data.Text.Internal.Fusion.Common

   O(1) Returns the first character of a Stream Char, which must be non-empty. This is a partial function, consider using uncons. Properties

   head . stream = head
   

4. head :: HasCallStack => Text -> Char

   text	Data.Text.Lazy

   O(1) Returns the first character of a Text, which must be non-empty. This is a partial function, consider using uncons instead.

5. head :: [a] -> a

   lens	Control.Lens.Internal.Doctest

   No documentation available.

6. head :: forall (m :: Type -> Type) a o . Monad m => ConduitT a o m (Maybe a)

   conduit	Data.Conduit.Combinators

   Take a single value from the stream, if available.

7. head :: forall (m :: Type -> Type) a o . Monad m => ConduitT a o m (Maybe a)

   conduit	Data.Conduit.List

   Take a single value from the stream, if available. Subject to fusion Since 0.3.0

8. head :: HasCallStack => [a] -> a

   hedgehog	Hedgehog.Internal.Prelude

   Extract the first element of a list, which must be non-empty. To disable the warning about partiality put {-# OPTIONS_GHC -Wno-x-partial -Wno-unrecognised-warning-flags #-} at the top of the file. To disable it throughout a package put the same options into ghc-options section of Cabal file. To disable it in GHCi put :set -Wno-x-partial -Wno-unrecognised-warning-flags into ~/.ghci config file. See also the migration guide.

   Examples

   >>> head [1, 2, 3]
   1
   

   >>> head [1..]
   1
   

   >>> head []
   *** Exception: Prelude.head: empty list
   

9. head :: NonEmpty a -> a

   base-compat	Data.List.NonEmpty.Compat

   Extract the first element of the stream.

10. head :: DList a -> a

    dlist	Data.DList

    head xs is the first element of xs. If xs is empty, an error is raised. <math>(1). head obeys the law:

    head xs = head (toList xs)
    

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