Implement most basic tuple

rtchallenge/src/lib.rs

@@ -0,0 +1 @@
+mod tuples;

rtchallenge/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

rtchallenge/src/tuples.rs

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+struct Tuple {
+    x: f32,
+    y: f32,
+    z: f32,
+    w: f32,
+}
+
+impl Tuple {
+    fn is_point(&self) -> bool {
+        self.w == 1.0
+    }
+
+    fn is_vector(&self) -> bool {
+        self.w == 0.0
+    }
+}
+
+fn tuple(x: f32, y: f32, z: f32, w: f32) -> Tuple {
+    Tuple { x, y, z, w }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::tuple;
+    #[test]
+    fn point() {
+        // A tuple with w = 1 is a point
+        let a = tuple(4.3, -4.2, 3.1, 1.0);
+        assert_eq!(a.x, 4.3);
+        assert_eq!(a.y, -4.2);
+        assert_eq!(a.z, 3.1);
+        assert_eq!(a.w, 1.0);
+        assert!(a.is_point());
+        assert!(!a.is_vector());
+    }
+    #[test]
+    fn vector() {
+        // A tuple with w = 0 is a point
+        let a = tuple(4.3, -4.2, 3.1, 0.0);
+        assert_eq!(a.x, 4.3);
+        assert_eq!(a.y, -4.2);
+        assert_eq!(a.z, 3.1);
+        assert_eq!(a.w, 0.0);
+        assert!(!a.is_point());
+        assert!(a.is_vector());
+    }
+}