1 files changed, 10 insertions, 6 deletions

diff --git a/src/Sequence/Contact/Types.hs b/src/Sequence/Contact/Types.hs
index c69a698..80d35d2 100644
--- a/src/Sequence/Contact/Types.hs
+++ b/src/Sequence/Contact/Types.hs
@@ -31,6 +31,7 @@ import Data.Dynamic.Lens
 
 import Control.Monad.Reader (ask, local)
 import Control.Monad.State
+import Control.Monad.Trans.Maybe
 
 import Sequence.Contact.Types.Internal
 
@@ -77,17 +78,17 @@ instance Show Effect where
   show = show . view effectName
 
 instance Default Effect where
-  def = Effect "" $ preview ctx
+  def = Effect "" mzero
 
 instance Monoid Effect where
   mempty = def
-  (Effect aName aEff) `mappend` (Effect bName bEff) = Effect name $ do
-    new <- aEff
+  (Effect aName aEff) `mappend` (Effect bName bEff) = Effect name . MaybeT $ do
+    new <- runMaybeT aEff
     maybe
       (id :: FormulaM Stats (Maybe Stats) -> FormulaM Stats (Maybe Stats))
       (local :: (Context Stats -> Context Stats) -> FormulaM Stats (Maybe Stats) -> FormulaM Stats (Maybe Stats))
       (set ctx <$> new :: Maybe (Context Stats -> Context Stats))
-      $ bEff
+      $ runMaybeT bEff
     where
       name
         | aName /= ""
@@ -97,6 +98,9 @@ instance Monoid Effect where
 effect :: String -> Effect
 effect str = def & set effectName str
 
+instance IsString Effect where
+  fromString = effect
+
 makeLenses ''Test
 
 instance Default Test where
@@ -106,7 +110,7 @@ instance Default Test where
         , _tCritFailureMod = 0
         , _tBaseDifficulty = 50
         , _tMod = 0
-        , _tEffect = const $ pure (def :: Effect)
+        , _tEffect = const mzero
         }
 
 deriving instance Eq TestResult
@@ -174,7 +178,7 @@ instance Default Stats where
         }
 
 applyModifier :: String -> (Test -> FormulaM Stats Test) -> Effect
-applyModifier effectName modifier = Effect (CI.mk effectName) $ previews ctx apply
+applyModifier effectName modifier = Effect (CI.mk effectName) . MaybeT $ previews ctx apply
   where
     apply = sModifiers <>~ [Modifier (CI.mk $ effectName ++ " (modifier)") modifier]