Calendar view

1 files changed, 20 insertions, 0 deletions

diff --git a/src/Util.hs b/src/Util.hs
index 1e10eec..95cc4ce 100644
--- a/src/Util.hs
+++ b/src/Util.hs
@@ -2,6 +2,8 @@
 module Util (module Util, toList) where
 
 import Data.Foldable (toList)
+import Data.Maybe (fromMaybe)
+import Data.Time (Day, toGregorian)
 import Data.Word (Word8)
 
 
@@ -32,3 +34,21 @@ pad c w val =
 
 uncurry3 :: (a -> b -> c -> d) -> (a, b, c) -> d
 uncurry3 f (x, y, z) = f x y z
+
+dropWhileEnd :: (a -> Bool) -> [a] -> [a]
+dropWhileEnd p = fromMaybe [] . go
+  where
+    go [] = Nothing
+    go (x:xs) =
+      case go xs of
+        Nothing | p x -> Nothing
+                | otherwise -> Just [x]
+        Just xs' -> Just (x : xs')
+
+ymdToString :: YMD -> String
+ymdToString (YMD y m d) = pad '0' 4 y ++ '-' : pad '0' 2 m ++ '-' : pad '0' 2 d
+
+dayToYMD :: Day -> YMD
+dayToYMD day =
+  let (y, m, d) = toGregorian day
+  in YMD (fromIntegral y) (fromIntegral m) (fromIntegral d)