Properties can now be satisfied differently on different operating systems.

1 files changed, 8 insertions, 0 deletions

diff --git a/Propellor/Property.hs b/Propellor/Property.hs
index 3e41fbcb..95d17c05 100644
--- a/Propellor/Property.hs
+++ b/Propellor/Property.hs
@@ -10,6 +10,7 @@ import "mtl" Control.Monad.Reader
 
 import Propellor.Types
 import Propellor.Types.Attr
+import Propellor.Attr
 import Propellor.Engine
 import Utility.Monad
 import System.FilePath
@@ -91,6 +92,13 @@ check c property = Property (propertyDesc property) $ ifM (liftIO c)
 	, return NoChange
 	)
 
+-- | Makes a property that is satisfied differently depending on the host's
+-- operating system. 
+--
+-- Note that the operating system may not be declared for some hosts.
+withOS :: Desc -> (Maybe System -> Propellor Result) -> Property
+withOS desc a = Property desc $ a =<< getOS
+
 boolProperty :: Desc -> IO Bool -> Property
 boolProperty desc a = Property desc $ ifM (liftIO a)
 	( return MadeChange