Small, small, refactoring + added comments

src/main.rs

@@ -30,7 +30,7 @@ enum ActorPosn {
         x: u8,
         y: u8,
     },
-    Floating {
+    Floating { //This probably needs some `previous position on board' fields
         x: f32,
         y: f32,
         held_x: f32,
@@ -47,6 +47,7 @@ struct Actor {
     behaviour: u8, //index into the behaviours array
 }
 
+
 fn make_grid(ctx: &mut Context, r: i32, c: i32, board: &[Vec<u8>]) -> GameResult<Mesh> {
     let mut builder = MeshBuilder::new();
 
@@ -60,16 +61,17 @@ fn make_grid(ctx: &mut Context, r: i32, c: i32, board: &[Vec<u8>]) -> GameResult
                     w: BOARD_SQUARE_SIZE,
                     h: BOARD_SQUARE_SIZE,
                 },
-                match board[row as usize][col as usize] {
+                match board[row as usize][col as usize] % 2 {
                     0 => Color::WHITE,
                     1 => Color::BLACK,
-                    2 => Color::RED,
+                    _ => Color::BLACK //impossible
+/*                    2 => Color::RED,
                     3 => Color::CYAN,
                     4 => Color::YELLOW,
                     5 => Color::GREEN,
                     6 => Color::BLUE,
                     7 => Color::MAGENTA,
-                    _ => Color::BLACK,
+                    _ => Color::BLACK,*/
                 },
             )?;
         }
@@ -88,6 +90,13 @@ fn make_board(r: i32, c: i32) -> Vec<Vec<u8>> {
     init
 }
 
+//I have moved this function out of the impl block for borrow checking reasons.
+//This should really only borrow self.col and self.row, but as a method it borrows everything.
+//As a result, I couldn't use this while iterating through actors.
+//Possible solution: Wrap `col' and `row' up as some kind of Dimensions struct, then make this a method on that struct.
+//Would then only borrow the dimensions.
+//http://smallcultfollowing.com/babysteps/blog/2018/11/01/after-nll-interprocedural-conflicts/
+
 fn closest_square_coords(x: f32, y: f32, col: i32, row: i32) -> (u8, u8) {
     //First, normalise to within the grid.
     let mut x = x;
@@ -131,10 +140,9 @@ impl Apr {
         })
     }
 
-    fn set_colour(&mut self, r: usize, c: usize, col: u8) -> GameResult<()> {
-        self.board[r][c] = col;
-        self.should_update_grid = true;
-        Ok(())
+    fn set_colour(&mut self, r: usize, c: usize, col: u8) { //You should only modify self.board through this method.
+        self.board[r][c] = col;                             //Making a getter for self.board would sadly break borrowing in the same way that closest_square_coords does.
+        self.should_update_grid = true;                     //Similar solutions apply.
     }
 }
 impl EventHandler for Apr {
@@ -193,12 +201,7 @@ impl EventHandler for Apr {
         graphics::draw(ctx, &self.grid, drawparams)?;
         for actor in &self.actors {
             match actor.posn {
-                Floating {
-                    x,
-                    y,
-                    held_x: _,
-                    held_y: _,
-                } => graphics::draw(ctx, &actor.image, drawparams.dest([x, y]))?,
+                Floating { x, y, .. } => graphics::draw(ctx, &actor.image, drawparams.dest([x, y]))?,
                 Board { x, y } => graphics::draw(
                     ctx,
                     &actor.image,