Rename everything from suffix 2 to 2d for clarity.

src/vec2d.rs

@@ -0,0 +1,64 @@
+use std::ops::Add;
+
+#[macro_export]
+macro_rules! v2 {
+    ( $x:expr, $y:expr ) => {
+        Vec2d::new($x, $y)
+    };
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct Vec2d {
+    pub x: i32,
+    pub y: i32,
+}
+
+impl Vec2d {
+    pub fn new(x: i32, y: i32) -> Vec2d {
+        Vec2d { x, y }
+    }
+
+    pub fn directions() -> Vec<Vec2d> {
+        vec![v2!(1, 0), v2!(0, 1), v2!(-1, 0), v2!(0, -1)]
+    }
+}
+
+impl Add for Vec2d {
+    type Output = Vec2d;
+
+    fn add(self, other: Vec2d) -> Vec2d {
+        let x = self.x + other.x;
+        let y = self.y + other.y;
+        Vec2d { x, y }
+    }
+}
+
+impl<'a> Add<&'a Vec2d> for Vec2d {
+    type Output = Vec2d;
+
+    fn add(self, other: &'a Vec2d) -> Vec2d {
+        let x = self.x + other.x;
+        let y = self.y + other.y;
+        Vec2d { x, y }
+    }
+}
+
+impl<'a> Add<Vec2d> for &'a Vec2d {
+    type Output = Vec2d;
+
+    fn add(self, other: Vec2d) -> Vec2d {
+        let x = self.x + other.x;
+        let y = self.y + other.y;
+        Vec2d { x, y }
+    }
+}
+
+impl<'a> Add<&'a Vec2d> for &'a Vec2d {
+    type Output = Vec2d;
+
+    fn add(self, other: &'a Vec2d) -> Vec2d {
+        let x = self.x + other.x;
+        let y = self.y + other.y;
+        Vec2d { x, y }
+    }
+}