replace case expressions with listToMaybe

lib/Track.hs

@@ -17,6 +17,7 @@ import Control.Exception
 import Data.List as List
 import Data.List qualified
 import Data.Map as Map
+import Data.Maybe
 import Data.Text qualified
 import Data.Text.Lazy as T
 import Data.Time
@@ -87,32 +88,20 @@ elToPoint c =
               >>= content
        in Point
             (Pos lat lon)
-            ( case ele of
-                [e] -> Just $ asFloat e
-                _ -> Nothing
-            )
+            ( (listToMaybe ele) >>= return . asFloat )
             ( case ts of
                 [e] -> case Data.Time.ISO8601.parseISO8601 (Data.Text.unpack e) of
                   Just utime -> utime
                   _ -> UTCTime (toEnum 0) 0
                 _ -> UTCTime (toEnum 0) 0
             )
-            ( case cadence of
-                [e] -> Just (asInt e)
-                _ -> Nothing
-            )
-            ( case power of
-                [e] -> Just (asInt e)
-                _ -> Nothing
-            )
+            ( (listToMaybe cadence) >>= return . asInt)
+            ( (listToMaybe power) >>= return . asInt)
             Nothing
       where
         asFloat v = (read (Data.Text.unpack v) :: Float)
         asInt v = (read (Data.Text.unpack v) :: Int)
-        getAttr name =
-          case Map.lookup name attrs of
-            Just v -> asFloat v
-            _ -> 0
+        getAttr name = maybe 0 asFloat (Map.lookup name attrs)
     _ -> mkPoint (Pos 0 0)
 
 getPoints :: Cursor -> [Point]