okasaki

commit 0c3f691b03ab6c1b2cbeb40b2ba69d5b78e04ae4
parent 33e86fc085de0b27b3847b07e909e99115ea0fa5
Author: Jared Tobin <jared@jtobin.io>
Date:   Sat,  4 Mar 2023 23:14:01 +0400

Cosmetic tweaks.

Diffstat:
M
lib/Okasaki/Stack.hs
 | 
13
+++++++------
M
lib/Okasaki/Tree.hs
 | 
1
-
M
lib/Okasaki/Tree/CPS.hs
 | 
4
++--

3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/lib/Okasaki/Stack.hs b/lib/Okasaki/Stack.hs
@@ -23,6 +23,7 @@ module Okasaki.Stack (
   ) where
 
 import Prelude hiding (map)
+import Data.Eq.Deriving (deriveEq1)
 import Data.Fix (Fix(..))
 import Data.Functor.Foldable as RS
 import Text.Show.Deriving
@@ -33,6 +34,7 @@ data StackF a r =
   deriving (Eq, Functor, Foldable, Traversable, Show)
 
 $(deriveShow1 ''StackF)
+$(deriveEq1 ''StackF)
 
 type Stack a = Fix (StackF a)
 
@@ -86,7 +88,7 @@ non s = case project s of
 cat :: Stack a -> Stack a -> Stack a
 cat l r = apo lag (project l) where
   lag = \case
-    NilF      -> fmap Left (project r)
+    NilF -> fmap Left (project r)
     ConsF h t -> case project t of
       NilF -> ConsF h (Left r)
       rest -> ConsF h (Right rest)
@@ -95,11 +97,10 @@ cat l r = apo lag (project l) where
 jab :: Int -> a -> Stack a -> Stack a
 jab n x s = apo lag (n, s) where
   lag (j, tac) = case project tac of
-    NilF      -> NilF
-    ConsF h t ->
-      if   j <= 0
-      then ConsF x (Left t)
-      else ConsF h (Right (pred j, t))
+    NilF -> NilF
+    ConsF h t
+      | j <= 0    -> ConsF x (Left t)
+      | otherwise -> ConsF h (Right (pred j, t))
 
 -- exercise 2.1
 
diff --git a/lib/Okasaki/Tree.hs b/lib/Okasaki/Tree.hs
@@ -20,7 +20,6 @@ module Okasaki.Tree (
 import Data.Eq.Deriving (deriveEq1)
 import Data.Fix hiding (cata, ana, hylo)
 import Data.Functor.Foldable
-import Data.Maybe (fromMaybe)
 import Data.Monoid
 import Okasaki.Orphans ()
 import qualified Okasaki.Tree.CPS as CPS
diff --git a/lib/Okasaki/Tree/CPS.hs b/lib/Okasaki/Tree/CPS.hs
@@ -54,8 +54,8 @@ nod x l r = Fix (nodF x l r)
 sin :: a -> Tree a
 sin x = nod x lef lef
 
-empty :: Tree a -> Bool
-empty (project -> TreeF c) = c True b where
+non :: Tree a -> Bool
+non (project -> TreeF c) = c True b where
   b _ _ _ = False
 
 -- exercise 2.3 (no unnecessary copying) (?)