Add documentation

Graphics/Command.hs

@@ -1,10 +1,15 @@
 module Graphics.Command where
 
-import FRP.Yampa (Time, Event)
+import FRP.Yampa (Event, Time)
 
+-- | A datatype representing all possible commands the user
+-- can give through UI.
 data Command
-  = Resize (Int, Int)
+  = -- | A command to resize the window to the given dimensions.
-  | ChangeSpeed (Time -> Time)
+    Resize (Int, Int)
+  | -- | A command to change the tick speed of the simulation,
+    -- given by a function on the period between ticks.
+    ChangeSpeed (Time -> Time)
 
 getResize :: Command -> Maybe (Int, Int)
 getResize (Resize size) = Just size
@@ -14,4 +19,5 @@ getChangeSpeed :: Command -> Maybe (Time -> Time)
 getChangeSpeed (ChangeSpeed f) = Just f
 getChangeSpeed _ = Nothing
 
+-- | An event signalling that a command has been given by the user.
 type CommandEvent = Event Command

Graphics/Display.hs

@@ -10,6 +10,7 @@ import Graphics.Gloss
 
 -- * Drawing the display grid
 
+-- | Draw a square with the given size and position.
 square :: Float -> Point -> Picture
 square size (x, y) = translate (x + size / 2) y (rectangleUpperSolid size size)
 
@@ -27,6 +28,7 @@ drawCells xs size =
   let poss = (,) <$> [0 .. sizex @f -1] <*> [0 .. sizey @f -1]
    in mapMaybe (\pos -> drawCell xs pos size) poss
 
+-- | Draw a grid of a displayable space given the window size and cell color.
 drawGrid :: forall f. DisplayableSpace f => (Int, Int) -> Color -> f Bool -> Picture
 drawGrid (w, h) c xs =
   let size = fromIntegral $ if w > h then h `div` sizey @f else w `div` sizex @f