initial commit

src/Bool.hs

@@ -0,0 +1,27 @@
+module Bool (
+    whenM
+  , unlessM
+  , ifM
+  , guardM
+  , bool
+  ) where
+
+import Prelude
+import Control.Monad (MonadPlus, when, unless, guard)
+
+bool :: a -> a -> Bool -> a
+bool f t p = if p then t else f
+
+whenM :: Monad m => m Bool -> m () -> m ()
+whenM p m =
+  p >>= flip when m
+
+unlessM :: Monad m => m Bool -> m () -> m ()
+unlessM p m =
+  p >>= flip unless m
+
+ifM :: Monad m => m Bool -> m a -> m a -> m a
+ifM p x y = p >>= \b -> if b then x else y
+
+guardM :: MonadPlus m => m Bool -> m ()
+guardM f = guard =<< f