Simple examples.

examples/Simple.hs

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+import Control.Monad
+import qualified Data.ByteString.Char8 as S
+import System.FilePath
+import System.FilePath.Find
+import System.FilePath.Manip
+import Text.Regex.Posix ((=~))
+
+
+
+-- Get a list of all symlinks.
+
+getDanglingLinks :: FilePath -> IO [FilePath]
+
+getDanglingLinks = find always (fileType ==? SymbolicLink &&?
+                                followStatus ==? Nothing)
+
+
+
+-- Rename all ".cpp" files to ".C".
+
+renameCppToC :: FilePath -> IO ()
+
+renameCppToC path = find always (extension ==? ".cpp") path >>=
+    mapM_ (renameWith (replaceExtension ".C"))
+
+
+
+-- A recursion control predicate that will avoid recursing into
+-- directories commonly used by revision control tools.
+
+noRCS :: RecursionPredicate
+
+noRCS = (`elem` ["_darcs","SCCS","CVS",".svn",".hg",".git"]) `liftM` fileName
+
+cSources :: FilePath -> IO [FilePath]
+
+cSources = find noRCS (extension ==? ".c" ||? extension ==? ".h")
+
+
+
+-- Replace all uses of "monkey" with "simian", saving the original copy
+-- of the file with a ".bak" extension:
+
+monkeyAround :: FilePath -> IO ()
+
+monkeyAround = modifyWithBackup (<.> "bak") (unwords . map reMonkey . words)
+    where reMonkey x = if x == "monkey" then "simian" else x
+
+
+
+-- Given a simple grep, it's easy to construct a recursive grep.
+
+grep :: (Int -> S.ByteString -> a) -> String -> S.ByteString -> [a]
+
+grep f pat s = consider 0 (S.lines s)
+    where consider _ [] = []
+          consider n (l:ls) | S.null l = consider (n+1) ls
+          consider n (l:ls) | l =~ pat = (f n l):ls'
+                            | otherwise = ls'
+              where ls' = consider (n+1) ls
+
+grepFile :: (Int -> S.ByteString -> a) -> String -> FilePath -> IO [a]
+
+grepFile f pat name = grep f pat `liftM` S.readFile name
+
+recGrep :: String -> FilePath -> IO [(FilePath, Int, S.ByteString)]
+
+recGrep pat top = find always (fileType ==? RegularFile) top >>=
+                  mapM ((,,) >>= flip grepFile pat) >>=
+                  return . concat