diff --git a/hfiar.cabal b/hfiar.cabal
--- a/hfiar.cabal
+++ b/hfiar.cabal
@@ -1,5 +1,5 @@
 name: hfiar
-version: 2.0.1
+version: 2.0.2
 cabal-version: >=1.6
 build-type: Custom
 license: BSD3
@@ -40,4 +40,4 @@
     buildable: True
     hs-source-dirs: src
     other-modules: HFiaR.GUI, HFiaR.Server
-    ghc-options: -fwarn-unused-imports -fwarn-missing-fields -fwarn-incomplete-patterns
+    ghc-options: -Wall
diff --git a/src/HFiaR.hs b/src/HFiaR.hs
--- a/src/HFiaR.hs
+++ b/src/HFiaR.hs
@@ -7,7 +7,7 @@
 -- * Types
     Game, Player(..), Tile(..), HFiaRError(..), HFiaRResult(..),
 -- * Actions
-    dropIn, player, board, result
+    dropIn, tryDropIn, player, board, result
     ) where
 
 import Control.Monad.State
@@ -75,26 +75,30 @@
 -- | Drop a tile in a column
 dropIn :: Monad m => Int -- ^ Column number
        -> HFiaRT m (Either HFiaRError ())
-dropIn c | c < 0 = return $ Left InvalidColumn
-         | 6 < c = return $ Left InvalidColumn
-         | otherwise =
-            do
-                game <- get
-                case game of
-                    Ended{} -> return $ Left GameEnded
-                    OnCourse{gameBoard = theBoard,
-                             gamePlayer= thePlayer} ->
-                        if length (theBoard !! c) == 7
-                            then return $ Left FullColumn
-                            else
-                                let newBoard = insertAt c (tiles thePlayer) theBoard
-                                    newResult= if (isWinner c thePlayer newBoard) then WonBy thePlayer else Tie
-                                    newGame  = if (full newBoard || (newResult == WonBy thePlayer))
-                                                   then Ended{gameResult = newResult,
-                                                              gameBoard  = newBoard}
-                                                   else OnCourse{gameBoard = newBoard,
-                                                                 gamePlayer= otherPlayer thePlayer}
-                                 in put newGame >>= return . Right
+dropIn c = do
+                res <- get >>= return . doDropIn c 
+                case res of
+                    Left err -> return $ Left err
+                    Right newGame -> put newGame >>= return . Right
+
+-- | Try (i.e. without actually doing it, returns the result of) dropping a tile in a column
+tryDropIn :: Monad m => Int -> HFiaRT m (Either HFiaRError Game)
+tryDropIn c = get >>= return . doDropIn c
+
+doDropIn :: Int -> Game -> Either HFiaRError Game
+doDropIn _ Ended{} = Left GameEnded
+doDropIn c OnCourse{gameBoard = theBoard,
+                    gamePlayer= thePlayer} | c < 0 = Left InvalidColumn
+                                           | 6 < c = Left InvalidColumn
+                                           | length (theBoard !! c) == 7 = Left FullColumn
+                                           | otherwise =
+                                                let newBoard = insertAt c (tiles thePlayer) theBoard
+                                                    newResult= if (isWinner c thePlayer newBoard) then WonBy thePlayer else Tie
+                                                 in if (full newBoard || (newResult == WonBy thePlayer))
+                                                       then Right Ended{gameResult = newResult,
+                                                                        gameBoard  = newBoard}
+                                                       else Right OnCourse{gameBoard = newBoard,
+                                                                           gamePlayer= otherPlayer thePlayer}
     where insertAt :: Int -> a -> [[a]] -> [[a]]
           insertAt i x xss = (take i xss) ++ ( (x : (xss !! i)) : drop (i+1) xss)