code cleanup

1 files changed, 12 insertions, 2 deletions

diff --git a/events/src/Events/Eval.hs b/events/src/Events/Eval.hs
index c5bc134..280c577 100644
--- a/events/src/Events/Eval.hs
+++ b/events/src/Events/Eval.hs
@@ -1,5 +1,9 @@
+{-# LANGUAGE ViewPatterns #-}
+
 module Events.Eval
   ( evaluate
+  , ordPredicate
+  , module Data.Ord
   ) where
 
 import Control.Monad.Fix (MonadFix(mfix))
@@ -10,7 +14,13 @@ import Data.Maybe (catMaybes)
 
 import Control.Lens
 
-evaluate :: MonadFix m => (Maybe Object -> StateT EvalCtx m Bool) -> Eval m () -> m [Object]
+import Data.Ord (Ordering(..))
+
+evaluate :: MonadFix m => (Maybe Object -> ReaderT EvalCtx m Bool) -> Eval m () -> m [Object]
 evaluate predicate x = catMaybes <$> mfix x'
   where
-    x' = evalStateT (foldNDT predicate (preview objCtx <$> execStateT x def)) . flip (set ctxEvents) def . catMaybes
+    x' = runReaderT (foldNDT predicate (preview objCtx <$> execStateT x def)) . flip (set ctxEvents) def . catMaybes
+
+ordPredicate :: Applicative m => (Object -> Ordering) -> (Maybe Object -> m Bool)
+ordPredicate _  Nothing        = pure True
+ordPredicate f (Just (f -> o)) = pure $ o <= EQ