Add commandline arguments splitting. (#76)

System/Win32/Console.hsc

@@ -25,13 +25,22 @@ module System.Win32.Console (
         setConsoleOutputCP,
         -- * Ctrl events
         CtrlEvent, cTRL_C_EVENT, cTRL_BREAK_EVENT,
-        generateConsoleCtrlEvent
+        generateConsoleCtrlEvent,
+        -- * Command line
+        commandLineToArgv
   ) where
 
 ##include "windows_cconv.h"
 
 import System.Win32.Types
 
+import Foreign.C.Types (CInt(..))
+import Foreign.C.String (withCWString, CWString)
+import Foreign.Ptr (Ptr)
+import Foreign.Storable (peek)
+import Foreign.Marshal.Array (peekArray)
+import Foreign.Marshal.Alloc (alloca)
+
 foreign import WINDOWS_CCONV unsafe "windows.h GetConsoleCP"
         getConsoleCP :: IO UINT
 
@@ -59,4 +68,18 @@ generateConsoleCtrlEvent e p
 foreign import WINDOWS_CCONV safe "windows.h GenerateConsoleCtrlEvent"
     c_GenerateConsoleCtrlEvent :: CtrlEvent -> DWORD -> IO BOOL
 
--- ToDo: lots more
+foreign import WINDOWS_CCONV unsafe "Shellapi.h CommandLineToArgvW"
+     c_CommandLineToArgvW :: CWString -> Ptr CInt -> IO (Ptr CWString)
+
+-- | This function can be used to parse commandline arguments and return
+--   the split up arguments as elements in a list.
+commandLineToArgv :: String -> IO [String]
+commandLineToArgv []  = return []
+commandLineToArgv arg =
+  do withCWString arg $ \c_arg -> do
+       alloca $ \c_size -> do
+         res <- c_CommandLineToArgvW c_arg c_size
+         size <- peek c_size
+         args <- peekArray (fromIntegral size) res
+         _ <- localFree res
+         mapM peekTString args

changelog.md

@@ -1,5 +1,9 @@
 # Changelog for [`Win32` package](http://hackage.haskell.org/package/Win32)
 
+## Unreleased GIT version
+
+* Add `commandLineToArgv`
+
 ## 2.5.1.0 *Feb 2017*
 
 * Add `withHandleToHANDLE` (originally found in the `ansi-terminal` library)