24 lines
748 B
Haskell
24 lines
748 B
Haskell
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import Data.List
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-- Return the common prefix of two lists.
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commonPrefix2 (x:xs) (y:ys) | x == y = x : commonPrefix2 xs ys
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commonPrefix2 _ _ = []
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-- Return the common prefix of zero or more lists.
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commonPrefix (xs:xss) = foldr commonPrefix2 xs xss
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commonPrefix _ = []
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-- Split a string into path components.
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splitPath = groupBy (\_ c -> c /= '/')
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-- Return the common prefix of zero or more paths.
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-- Note that '/' by itself is not considered a path component,
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-- so "/" and "/foo" are treated as having nothing in common.
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commonDirPath = concat . commonPrefix . map splitPath
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main = putStrLn $ commonDirPath [
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"/home/user1/tmp/coverage/test",
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"/home/user1/tmp/covert/operator",
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"/home/user1/tmp/coven/members"
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]
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