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diff --git a/Propellor/Property.hs b/Propellor/Property.hs
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+{-# LANGUAGE PackageImports #-}
+
+module Propellor.Property where
+
+import System.Directory
+import Control.Monad
+import Data.Monoid
+import Control.Monad.IfElse
+import "mtl" Control.Monad.Reader
+
+import Propellor.Types
+import Propellor.Types.Attr
+import Propellor.Engine
+import Utility.Monad
+
+makeChange :: IO () -> Propellor Result
+makeChange a = liftIO a >> return MadeChange
+
+noChange :: Propellor Result
+noChange = return NoChange
+
+-- | Combines a list of properties, resulting in a single property
+-- that when run will run each property in the list in turn,
+-- and print out the description of each as it's run. Does not stop
+-- on failure; does propigate overall success/failure.
+propertyList :: Desc -> [Property] -> Property
+propertyList desc ps = Property desc $ ensureProperties ps
+
+-- | Combines a list of properties, resulting in one property that
+-- ensures each in turn, stopping on failure.
+combineProperties :: Desc -> [Property] -> Property
+combineProperties desc ps = Property desc $ go ps NoChange
+  where
+  	go [] rs = return rs
+	go (l:ls) rs = do
+		r <- ensureProperty l
+		case r of
+			FailedChange -> return FailedChange
+			_ -> go ls (r <> rs)
+
+-- | Combines together two properties, resulting in one property
+-- that ensures the first, and if the first succeeds, ensures the second.
+-- The property uses the description of the first property.
+before :: Property -> Property -> Property
+p1 `before` p2 = Property (propertyDesc p1) $ do
+	r <- ensureProperty p1
+	case r of
+		FailedChange -> return FailedChange
+		_ -> ensureProperty p2
+
+-- | Makes a perhaps non-idempotent Property be idempotent by using a flag
+-- file to indicate whether it has run before.
+-- Use with caution.
+flagFile :: Property -> FilePath -> Property
+flagFile property flagfile = Property (propertyDesc property) $
+	go =<< liftIO (doesFileExist flagfile)
+  where
+	go True = return NoChange
+	go False = do
+		r <- ensureProperty property
+		when (r == MadeChange) $ liftIO $ 
+			unlessM (doesFileExist flagfile) $
+				writeFile flagfile ""
+		return r
+
+--- | Whenever a change has to be made for a Property, causes a hook
+-- Property to also be run, but not otherwise.
+onChange :: Property -> Property -> Property
+property `onChange` hook = Property (propertyDesc property) $ do
+	r <- ensureProperty property
+	case r of
+		MadeChange -> do
+			r' <- ensureProperty hook
+			return $ r <> r'
+		_ -> return r
+
+(==>) :: Desc -> Property -> Property
+(==>) = flip describe
+infixl 1 ==>
+
+-- | Makes a Property only be performed when a test succeeds.
+check :: IO Bool -> Property -> Property
+check c property = Property (propertyDesc property) $ ifM (liftIO c)
+	( ensureProperty property
+	, return NoChange
+	)
+
+boolProperty :: Desc -> IO Bool -> Property
+boolProperty desc a = Property desc $ ifM (liftIO a)
+	( return MadeChange
+	, return FailedChange
+	)
+
+-- | Undoes the effect of a property.
+revert :: RevertableProperty -> RevertableProperty
+revert (RevertableProperty p1 p2) = RevertableProperty p2 p1
+
+-- | Starts accumulating the properties of a Host.
+--
+-- > host "example.com"
+-- > 	& someproperty
+-- > 	! oldproperty
+-- > 	& otherproperty
+host :: HostName -> Host
+host hn = Host [] (\_ -> newAttr hn)
+
+-- | Adds a property to a Host
+-- Can add Properties, RevertableProperties, and AttrProperties
+(&) :: IsProp p => Host -> p -> Host
+(Host ps as) & p = Host (ps ++ [toProp p]) (getAttr p . as)
+
+infixl 1 &
+
+-- | Adds a property to the Host in reverted form.
+(!) :: Host -> RevertableProperty -> Host
+(Host ps as) ! p = Host (ps ++ [toProp q]) (getAttr q . as)
+  where
+	q = revert p
+
+infixl 1 !