Refactor and reformat

app/Main.hs

@@ -7,24 +7,34 @@ import Linear.V3
 
 import Graphics.Gloss hiding (Point)
 
+
+--------------------------------------------------------------------------------
+-- CSV export
+--------------------------------------------------------------------------------
+
 csvFromPoint :: Point V3 Double -> String
 csvFromPoint (P (V3 x y z)) =
   show x ++ "," ++ show y ++ "," ++ show z
 
 csvFromBodies :: [Body] -> [String]
-csvFromBodies [] = []
-csvFromBodies (x:xs) =
-  (bodyName x ++ ","
-    ++ (show $ bodyMass x) ++ ","
-    ++ (csvFromPoint $ bodyPosition x) ++ "\n")
-  :(csvFromBodies xs)
+csvFromBodies =
+  map (\ x ->
+         bodyName x ++
+        "," ++
+        show (bodyMass x) ++
+        "," ++ csvFromPoint (bodyPosition x) ++ "\n")
   
 steps :: Int -> Double -> [Body] -> IO ()
 steps 0 _ _ = return ()
 steps n dt bodies = do
-  putStr . concat $ map ((++) (show n ++ ",")) $ csvFromBodies bodies
+  putStr . concat $ map ((show n ++ ",") ++) $ csvFromBodies bodies
   steps (n-1) dt (updateAll dt bodies)
 
+
+--------------------------------------------------------------------------------
+-- Gloss
+--------------------------------------------------------------------------------
+
 width, height, offset :: Int
 width = 1000
 height = 750
@@ -38,7 +48,7 @@ displayBody b = translate (realToFrac x/1e9) (realToFrac y/1e9) $ circle (realTo
   where P (V3 x y _) = bodyPosition b
 
 displayBodies :: [Body] -> Picture
-displayBodies = (color white) . Pictures . (map displayBody)
+displayBodies = color white . Pictures . map displayBody
 
 drawing :: Picture
 drawing = color white $ circle 80

src/Lib.hs

@@ -1,11 +1,6 @@
 module Lib (
   gravity,
-  Body,
-  bodyName,
-  bodyRadius,
-  bodyMass,
-  bodyPosition,
-  bodySpeed,
+  Body(..),
   bodyDistance,
   field,
   acceleration,
@@ -55,14 +50,14 @@ bodyDistance body1 body2 =
 -- Field created by a body on a certain position
 field :: Body -> Point V3 Double -> V3 Double
 field body pos =
-  unP $ (gravity * m / r**2) *^ (normalize vec)
+  unP $ (gravity * m / r**2) *^ normalize vec
   where m = bodyMass body
-        vec = (bodyPosition body) - pos
+        vec = bodyPosition body - pos
         r = norm vec
 
 -- Acceleration given to a body by its neighbours
 acceleration :: Body -> [Body] -> V3 Double
-acceleration body = foldr f (fromInteger 0)
+acceleration body = foldr f 0
   where f neighbour acc =
           acc + field neighbour (bodyPosition body)
 
@@ -81,7 +76,7 @@ update dt (Body name r m pos speed) neighbours =
 
 -- Update all bodies with a timestep dt
 updateAll :: Double -> [Body] -> [Body]
-updateAll dt bodies = aux [] [] bodies
+updateAll dt = aux [] []
   where
     -- Cycles through all bodies, updates each one and stores it in
     -- res. Each body already updated is moved to prev.