Submission #1519969

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Source Code Expand

main = interact $ show . subtract . map read . lines

Submission Info

Compile Error

Main.hs:1:19:
    No instance for (Show ([b0] -> [b0]))
      (maybe you haven't applied enough arguments to a function?)
      arising from a use of ‘show’
    In the first argument of ‘(.)’, namely ‘show’
    In the second argument of ‘($)’, namely
      ‘show . subtract . map read . lines’
    In the expression: interact $ show . subtract . map read . lines

Main.hs:1:26:
    No instance for (Num [b0]) arising from a use of ‘subtract’
    In the first argument of ‘(.)’, namely ‘subtract’
    In the second argument of ‘(.)’, namely
      ‘subtract . map read . lines’
    In the second argument of ‘($)’, namely
      ‘show . subtract . map read . lines’

Main.hs:1:41:
    No instance for (Read b0) arising from a use of ‘read’
    The type variable ‘b0’ is ambiguous
    Note: there are several potential instances:
      instance (GHC.Arr.Ix a, Read a, Read b) => Read (GHC.Arr.Array a b)
        -- Defined in ‘GHC.Read’
      instance Read a => Read (Maybe a) -- Defined in ‘GHC.Read’
      instance (Integral ...