some basic map-drawing

src/grid.rs

@@ -23,7 +23,7 @@ fn main() {
 
     let get_cell = |x: usize, y: usize| {
         let idx = x + y * rows;
-        MAP[idx]
+        MAP.get(idx)
     };
 
     for (x, y) in iproduct!(0..rows-1, 0..cols-1) {
@@ -31,7 +31,9 @@ fn main() {
         let yc = y_offset + y as f64 * N;
         let d = N / 5.0;
         let cs = N / 10.0;
-        if get_cell(x, y) != get_cell(x + 1, y) {
+        if get_cell(x, y)
+            .and_then(|l| get_cell(x + 1, y)
+                      .and_then(|r| l != r)).unwrap_or(false) {
             drawing.add(gt::line(xc+N, yc).to(xc+N, yc+N));
 
             let xt = if get_cell(x, y) == '0' as u8 {
@@ -44,7 +46,7 @@ fn main() {
                 drawing.add(gt::line(xc+N, yt).to(xt, yt));
             }
 
-        } else if get_cell(x, y) == '1' as u8 {
+        } else if get_cell(x, y).unwrap() == '1' as u8 {
             for n in 1..5 {
                 drawing.add(gt::line(xc+N, yc + d * n as f64));
             }
@@ -63,7 +65,7 @@ fn main() {
                 drawing.add(gt::line(xt, yc+N).to(xt, yt));
             }
 
-        } else if get_cell(x, y) == '1' as u8 {
+        } else if get_cell(x, y).unwrap() == '1' as u8 {
             for n in 1..5 {
                 drawing.add(gt::line(xc + d * n as f64, yc+N));
             }