finished exercises on Course.Comonad

miladz68 · Dec 27, 2016 · 19a8e58 · 19a8e58
1 parent 1dfba10
commit 19a8e58
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/src/Course/Comonad.hs b/src/Course/Comonad.hs
@@ -32,8 +32,7 @@ instance Comonad Id where
   copure ::
     Id a
     -> a
-  copure =
-    error "todo: Course.Comonad copure#instance Id"
+  copure (Id a) = a
 
 -- | Witness that all things with (<<=) and copure also have (<$>).
 --
@@ -44,5 +43,4 @@ instance Comonad Id where
   (a -> b)
   -> f a
   -> f b
-(<$>) =
-  error "todo: Course.Comonad#(<$>)"
+(<$>) f = (<<=) (f.copure)