Some quick mediocre map-ish experiments

Cargo.toml

@@ -14,4 +14,8 @@ path = "src/circles.rs"
 
 [[bin]]
 name = "hexes"
-path = "src/hexes.rs"
+path = "src/hexes.rs"
+
+[[bin]]
+name = "grid"
+path = "src/grid.rs"

src/grid.rs

@@ -14,7 +14,7 @@ const MAP: &'static [u8] =
 fn main() {
     let (w, h) = (11.0, 14.0);
     let mut drawing = gt::svg(w, h);
-    drawing.add(gt::rect((0.0, 0.0), (11.0, 14.0)));
+    // drawing.add(gt::rect((0.0, 0.0), (11.0, 14.0)));
     const N: f64 = 0.5;
     let rows: usize = ((w - 1.0) / N).floor() as usize;
     let cols: usize = ((h - 1.0) / N).floor() as usize;
@@ -23,7 +23,11 @@ fn main() {
 
     let get_cell = |x: usize, y: usize| {
         let idx = x + y * rows;
-        MAP.get(idx)
+        if idx < MAP.len() {
+            Some(MAP[idx] as char)
+        } else {
+            None
+        }
     };
 
     for (x, y) in iproduct!(0..rows-1, 0..cols-1) {
@@ -33,10 +37,10 @@ fn main() {
         let cs = N / 10.0;
         if get_cell(x, y)
             .and_then(|l| get_cell(x + 1, y)
-                      .and_then(|r| l != r)).unwrap_or(false) {
+                      .map(|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 {
+            let xt = if get_cell(x, y) == Some('0') {
                 xc + N - 0.1
             } else {
                 xc + N + 0.1
@@ -46,16 +50,18 @@ fn main() {
                 drawing.add(gt::line(xc+N, yt).to(xt, yt));
             }
 
-        } else if get_cell(x, y).unwrap() == '1' as u8 {
+        } else if get_cell(x, y) == Some('1') {
             for n in 1..5 {
                 drawing.add(gt::line(xc+N, yc + d * n as f64));
             }
         }
 
-        if get_cell(x, y) != get_cell(x, y+1) {
+        if get_cell(x, y)
+            .and_then(|l| get_cell(x, y+1)
+                      .map(|r| l != r)).unwrap_or(false) {
             drawing.add(gt::line(xc, yc+N).to(xc+N, yc+N));
 
-            let yt = if get_cell(x, y) == '0' as u8 {
+            let yt = if get_cell(x, y) == Some('0') {
                 yc + N - 0.1
             } else {
                 yc + N + 0.1
@@ -65,7 +71,7 @@ fn main() {
                 drawing.add(gt::line(xt, yc+N).to(xt, yt));
             }
 
-        } else if get_cell(x, y).unwrap() == '1' as u8 {
+        } else if get_cell(x, y) == Some('1') {
             for n in 1..5 {
                 drawing.add(gt::line(xc + d * n as f64, yc+N));
             }