Branch is a strong data type

src/BranchParse.hs

@@ -1,11 +1,12 @@
 module BranchParse where
 
-import Control.Applicative ((<$>), (<*>), (<*), (*>), (<$))
+import Control.Applicative ((<$>), (<*>), (<*), (*>), (<$), pure)
 import Text.Parsec (digit, string, char, eof, anyChar, 
 				   many, many1, manyTill, noneOf, between,
 				   parse, ParseError, (<|>), try)
 import Text.Parsec.String (Parser)
-import Test.QuickCheck (Arbitrary(arbitrary), oneof, getPositive)
+import Test.QuickCheck (Arbitrary(arbitrary), oneof, getPositive, suchThat)
+import Data.List (isPrefixOf, isSuffixOf, isInfixOf)
 
 {-
  The idea is to parse the first line of the git status command.
@@ -32,15 +33,30 @@ instance Arbitrary Distance where
 		where
 			pos = getPositive <$> arbitrary
 
-type Branch = String
+{- Branch type -}
+
+newtype Branch = MkBranch String deriving (Show, Eq)
+
+isValidBranch :: String -> Bool
+isValidBranch b = not . or $ [null,
+							 (' ' `elem`),
+							 (".." `isInfixOf`),
+							 ("." `isPrefixOf`),
+							 ("." `isSuffixOf`)]
+							 <*> pure b
+
+instance Arbitrary Branch where
+	arbitrary = MkBranch <$> arbitrary `suchThat` isValidBranch
+
+
 type BranchInfo = ((Maybe Branch, Maybe Branch), Maybe Distance)
 
 noBranchInfo :: BranchInfo
 noBranchInfo = ((Nothing, Nothing), Nothing)
 
 newRepo :: Parser BranchInfo
 newRepo = 
-	fmap (\ branch -> ((Just branch, Nothing), Nothing))
+	fmap (\ branch -> ((Just $ MkBranch branch, Nothing), Nothing))
 		$ string "Initial commit on " *> many anyChar <* eof
 
 noBranch :: Parser BranchInfo
@@ -49,24 +65,24 @@ noBranch =
 		<$ manyTill anyChar (try $ string " (no branch)") <* eof
 
 trackedBranch :: Parser Branch
-trackedBranch = manyTill anyChar (try $ string "...")
+trackedBranch = MkBranch <$> manyTill anyChar (try $ string "...")
 
 branchRemoteTracking :: Parser BranchInfo
 branchRemoteTracking = 
-	(\ branch tracking behead -> ((Just branch, Just tracking), Just behead))
+	(\ branch tracking behead -> ((Just branch, Just $ MkBranch tracking), Just behead))
 		<$> trackedBranch
 		<*> many (noneOf " ") <* char ' '
 		<*> inBrackets
 
 branchRemote :: Parser BranchInfo
 branchRemote = 
-	(\ branch tracking -> ((Just branch, Just tracking), Nothing))
+	(\ branch tracking -> ((Just branch, Just $ MkBranch tracking), Nothing))
 		<$> trackedBranch
 		<*> many (noneOf " ") <* eof
 
 branchOnly :: Parser BranchInfo
 branchOnly = 
-	(\ branch -> ((Just branch, Nothing), Nothing))
+	(\ branch -> ((Just $ MkBranch branch, Nothing), Nothing))
 		<$> many (noneOf " ") <* eof
 
 branchParser :: Parser BranchInfo

src/Main.hs

@@ -2,7 +2,7 @@ import System.Process (readProcessWithExitCode)
 import System.Exit (ExitCode(ExitSuccess))
 import Data.Maybe (fromMaybe)
 import Control.Applicative ((<$>), (<*>))
-import BranchParse (Branch, BranchInfo, branchInfo, Distance, pairFromDistance)
+import BranchParse (Branch(MkBranch), BranchInfo, branchInfo, Distance, pairFromDistance)
 import StatusParse (Status(MakeStatus), processStatus)
 import Data.List (intercalate)
 
@@ -60,7 +60,7 @@ branchOrHash :: Maybe Branch -> IO String
 branchOrHash branch =
 	case branch of
 		Nothing -> makeHashWith ':' <$> gitrevparse
-		Just bn -> return bn
+		Just (MkBranch bn) -> return bn
 
 allInfo :: (BranchInfo, Status Int) -> (IO String, Numbers)
 allInfo (((branch, _), behead), stat) = (branchOrHash branch, showBranchNumbers behead ++ showStatusNumbers stat)

src/TestBranchParse.hs

@@ -1,22 +1,5 @@
-import BranchParse (BranchInfo, branchInfo, Distance)
-import Test.QuickCheck (Arbitrary(arbitrary), property, stdArgs, maxSuccess, quickCheckWith, suchThat)
-import Data.List (isPrefixOf, isSuffixOf, isInfixOf)
-import Control.Applicative ((<$>), (<*>), pure)
-
-{- ValidBranch type -}
-
-newtype ValidBranch = MkBranch String deriving (Show, Eq)
-
-isValidBranch :: String -> Bool
-isValidBranch b = not . or $ [null,
-							 (' ' `elem`),
-							 (".." `isInfixOf`),
-							 ("." `isPrefixOf`),
-							 ("." `isSuffixOf`)]
-							 <*> pure b
-
-instance Arbitrary ValidBranch where
-	arbitrary = MkBranch <$> arbitrary `suchThat` isValidBranch
+import BranchParse (BranchInfo, branchInfo, Distance, Branch(MkBranch))
+import Test.QuickCheck (property, stdArgs, maxSuccess, quickCheckWith)
 
 
 {- Helper to tackle the Either type -}
@@ -30,34 +13,34 @@ checkRight b s = expectRight b $ branchInfo s
 
 {- Test -}
 
-propNoBranch :: ValidBranch -> Bool
+propNoBranch :: Branch -> Bool
 propNoBranch (MkBranch s) =
 		checkRight
 			((Nothing, Nothing), Nothing)
 			$ s ++ " (no branch)"
 
-propNewRepo :: ValidBranch -> Bool
-propNewRepo (MkBranch s) =
+propNewRepo :: Branch -> Bool
+propNewRepo b@(MkBranch s) =
 		checkRight 
-			((Just s, Nothing), Nothing)
+			((Just b, Nothing), Nothing)
 			$ "Initial commit on " ++ s
 
-propBranchOnly :: ValidBranch -> Bool
-propBranchOnly (MkBranch s) = 
+propBranchOnly :: Branch -> Bool
+propBranchOnly b@(MkBranch s) = 
 		checkRight 
-			((Just s, Nothing), Nothing)
+			((Just b, Nothing), Nothing)
 			s
 
-propBranchRemote :: ValidBranch -> ValidBranch -> Bool
-propBranchRemote (MkBranch b) (MkBranch t) =
+propBranchRemote :: Branch -> Branch -> Bool
+propBranchRemote b'@(MkBranch b) t'@(MkBranch t) =
 		checkRight
-			((Just b, Just t), Nothing)
+			((Just b', Just t'), Nothing)
 			$ b ++"..." ++ t 
 
-propBranchRemoteTracking :: ValidBranch -> ValidBranch -> Distance -> Bool
-propBranchRemoteTracking (MkBranch b) (MkBranch t) distance = 
+propBranchRemoteTracking :: Branch -> Branch -> Distance -> Bool
+propBranchRemoteTracking b'@(MkBranch b) t'@(MkBranch t) distance = 
 		checkRight 
-			((Just b, Just t), Just distance)
+			((Just b', Just t'), Just distance)
 		 	$ b ++ "..." ++ t ++ " " ++ show distance
 
 main :: IO()