Applying remarks from blog post comments

Implementation of a strict readFile (from Mike Tolly).
Using the nicer notation from Erik Hesselink.

Puppet/Interpreter/Functions.hs

@@ -12,20 +12,20 @@ module Puppet.Interpreter.Functions
     ,pdbresourcequery
     ) where
 
-import Prelude hiding (catch)
-import Control.Exception
 import PuppetDB.Rest
 import Puppet.Printers
 import Puppet.Interpreter.Types
+import Puppet.Utils
 
+import Prelude hiding (catch)
+import Control.Exception
 import Data.Hash.MD5
 import qualified Crypto.Hash.SHA1 as SHA1
 import qualified Data.ByteString.Char8 as BS
 import Data.String.Utils (join,replace)
 import Text.RegexPR
 import Text.Regex.PCRE.String
 import Control.Monad.Error
-import System.IO
 import qualified Data.ByteString.Base16 as B16
 import SafeProcess
 import Data.Either (lefts, rights)
@@ -88,7 +88,9 @@ versioncmp a b | a > b = 1
 file :: [String] -> IO (Maybe String)
 file [] = return Nothing
 -- this is bad, is should be rewritten as a ByteString
-file (x:xs) = catch (fmap Just (withFile x ReadMode (\fh -> do { y <- hGetContents fh; evaluate (length y); return y }))) ((\_ -> file xs) :: SomeException -> IO (Maybe String))
+file (x:xs) = catch
+    (fmap Just (readFile' x))
+    (\SomeException{} -> file xs)
 
 puppetSplit :: String -> String -> IO (Either String [String])
 puppetSplit str reg = do

Puppet/Utils.hs

@@ -1,12 +1,15 @@
 {-# LANGUAGE CPP, ForeignFunctionInterface #-}
 
-module Puppet.Utils (mGetExecutablePath) where
+module Puppet.Utils (mGetExecutablePath, readFile', readSymbolicLink) where
 
 -- copy pasted from base 4.6.0.0
-
+import Prelude hiding (catch)
 import Foreign.C
 import Foreign.Marshal.Array
 import System.Posix.Internals
+import System.IO
+import Control.Exception
+
 
 foreign import ccall unsafe "readlink" c_readlink :: CString -> CString -> CSize -> IO CInt
 
@@ -26,3 +29,10 @@ readSymbolicLink file =
 mGetExecutablePath :: IO FilePath
 mGetExecutablePath = readSymbolicLink $ "/proc/self/exe"
 
+-- | Strict readFile
+readFile' f = do
+    h <- openFile f ReadMode
+    s <- hGetContents h
+    evaluate (length s)
+    return s
+