5 files changed, 37 insertions, 14 deletions
diff --git a/src/Propellor/Property.hs b/src/Propellor/Property.hs
index 1a40bb75..706e684b 100644
--- a/src/Propellor/Property.hs
+++ b/src/Propellor/Property.hs
@@ -16,7 +16,6 @@ module Propellor.Property (
 	, check
 	, fallback
 	, revert
-	, applyToList
 	-- * Property descriptions
 	, describe
 	, (==>)
@@ -54,7 +53,6 @@ import System.Posix.Files
 import qualified Data.Hash.MD5 as MD5
 import Data.List
 import Control.Applicative
-import Data.Foldable hiding (and, elem)
 import Prelude
 
 import Propellor.Types
@@ -353,14 +351,6 @@ unsupportedOS' = go =<< getOS
 revert :: RevertableProperty setup undo -> RevertableProperty undo setup
 revert (RevertableProperty p1 p2) = RevertableProperty p2 p1
 
--- | Apply a property to each element of a list.
-applyToList
-	:: (Foldable t, Functor t, Combines p p, p ~ CombinedType p p)
-	=> (b -> p)
-	-> t b
-	-> p
-prop `applyToList` xs = Data.Foldable.foldr1 before $ prop <$> xs
-
 makeChange :: IO () -> Propellor Result
 makeChange a = liftIO a >> return MadeChange
 
@@ -368,7 +358,7 @@ noChange :: Propellor Result
 noChange = return NoChange
 
 doNothing :: SingI t => Property (MetaTypes t)
-doNothing = property'' "noop property" Nothing
+doNothing = mempty
 
 -- | Registers an action that should be run at the very end, after
 -- propellor has checks all the properties of a host.
diff --git a/src/Propellor/Property/Apt.hs b/src/Propellor/Property/Apt.hs
index 4490aa95..c681eee6 100644
--- a/src/Propellor/Property/Apt.hs
+++ b/src/Propellor/Property/Apt.hs
@@ -265,7 +265,7 @@ pinnedTo
 	:: [AptPackagePref]
 	-> [(DebianSuite, PinPriority)]
 	-> RevertableProperty Debian Debian
-pinnedTo ps pins = (\p -> pinnedTo' p pins) `applyToList` ps
+pinnedTo ps pins = mconcat (map (\p -> pinnedTo' p pins) ps)
 	`describe` unwords (("pinned to " ++ showSuites):ps)
   where
 	showSuites = intercalate "," $ showSuite . fst <$> pins
diff --git a/src/Propellor/Property/Firejail.hs b/src/Propellor/Property/Firejail.hs
index b7841e07..6e877683 100644
--- a/src/Propellor/Property/Firejail.hs
+++ b/src/Propellor/Property/Firejail.hs
@@ -22,7 +22,7 @@ installed = Apt.installed ["firejail"]
 --
 -- See "DESKTOP INTEGRATION" in firejail(1).
 jailed :: [String] -> Property DebianLike
-jailed ps = (jailed' `applyToList` ps)
+jailed ps = mconcat (map jailed' ps)
 	`requires` installed
 	`describe` unwords ("firejail jailed":ps)
 
diff --git a/src/Propellor/Types.hs b/src/Propellor/Types.hs
index 6554abd2..690c153a 100644
--- a/src/Propellor/Types.hs
+++ b/src/Propellor/Types.hs
@@ -205,3 +205,35 @@ class TightenTargets p where
 
 instance TightenTargets Property where
 	tightenTargets (Property _ d a i c) = Property sing d a i c
+
+-- | Any type of Property is a monoid. When properties x and y are
+-- appended together, the resulting property has a description like
+-- "x and y". Note that when x fails to be ensured, it will not
+-- try to ensure y.
+instance SingI metatypes => Monoid (Property (MetaTypes metatypes))
+  where
+	mempty = Property sing "noop property" Nothing mempty mempty
+	mappend (Property _ d1 a1 i1 c1) (Property _ d2 a2 i2 c2) =
+	  	Property sing d (a1 <> a2) (i1 <> i2) (c1 <> c2)
+	  where
+		-- Avoid including "noop property" in description
+		-- when using eg mconcat.
+		d = case (a1, a2) of
+			(Just _, Just _) -> d1 <> " and " <> d2
+			(Just _, Nothing) -> d1
+			(Nothing, Just _) -> d2
+			(Nothing, Nothing) -> d1
+
+-- | Any type of RevertableProperty is a monoid. When revertable 
+-- properties x and y are appended together, the resulting revertable
+-- property has a description like "x and y".
+-- Note that when x fails to be ensured, it will not try to ensure y.
+instance
+	( Monoid (Property setupmetatypes)
+	, Monoid (Property undometatypes)
+	)
+	=> Monoid (RevertableProperty setupmetatypes undometatypes)
+  where
+	mempty = RevertableProperty mempty mempty
+	mappend (RevertableProperty s1 u1) (RevertableProperty s2 u2) =
+		RevertableProperty (s1 <> s2) (u2 <> u1)
diff --git a/src/Propellor/Types/Core.hs b/src/Propellor/Types/Core.hs
index dcd206eb..a805f561 100644
--- a/src/Propellor/Types/Core.hs
+++ b/src/Propellor/Types/Core.hs
@@ -48,9 +48,10 @@ instance LiftPropellor Propellor where
 instance LiftPropellor IO where
 	liftPropellor = liftIO
 
+-- | When two actions are appended together, the second action
+-- is only run if the first action does not fail.
 instance Monoid (Propellor Result) where
 	mempty = return NoChange
-	-- | The second action is only run if the first action does not fail.
 	mappend x y = do
 		rx <- x
 		case rx of