Update examples

testsuite/objc/expression_parser/PluginEvalAux.hs

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+{-# OPTIONS -fglasgow-exts -fffi #-}
+
+module PluginEvalAux where
+
+import System.Plugins.Make
+import System.Plugins.Load
+import System.Plugins.Utils
+
+import Foreign.C
+import Control.Exception        ( evaluate )
+import System.IO
+import System.Directory         ( renameFile, removeFile )
+
+symbol = "resource"
+
+evalWithStringResult :: FilePath -> String -> IO String
+evalWithStringResult srcFile s = do
+  status <- make srcFile ["-Onot"]
+  case status of
+      MakeFailure err   -> putStrLn "error occured" >> return (show err)
+      MakeSuccess _ obj -> load' obj
+  where
+    load' obj = do
+      loadResult <- load obj [] [] symbol
+      case loadResult of
+        LoadFailure errs -> putStrLn "load error" >> return (show errs)
+	LoadSuccess m (rsrc :: String -> IO String) -> do
+	  v' <- rsrc s
+	  unload m
+	  mapM_ removeFile [ obj, replaceSuffix obj ".hi" ]
+	  return v'
+
+foreign export ccall evalhaskell_CString :: CString -> CString -> IO CString
+
+evalhaskell_CString :: CString -> CString -> IO CString
+evalhaskell_CString filePathCS sCS = do
+  s <- peekCString sCS
+  filePath <- peekCString filePathCS
+  retval <- evalWithStringResult filePath s
+  newCString retval
+
+-- vi:sw=2 sts=2
+