Am I missing something? It seems I don’t have the list difference operator defined…
$ ghci
GHCi, version 8.6.5: http://www.haskell.org/ghc/ :? for help
Prelude> "Hello World!" \\ "ell W"
<interactive>:1:16: error:
Variable not in scope: (\\) :: [Char] -> [Char] -> t
Prelude> :t (\\)
<interactive>:1:1: error: Variable not in scope: \\
Prelude> :type (\\)
<interactive>:1:1: error: Variable not in scope: \\
Prelude> :type (++)
(++) :: [a] -> [a] -> [a]
Did it get removed? (And if so, where do I look to see that?)
>Solution :
It’s in Data.List:
% ghci
GHCi, version 8.4.4: http://www.haskell.org/ghc/ :? for help
Prelude> :t (\\)
<interactive>:1:1: error: Variable not in scope: \\
Prelude> import Data.List
Prelude Data.List> :t (\\)
(\\) :: Eq a => [a] -> [a] -> [a]