create iterator structure

src/circle.rs

@@ -0,0 +1,18 @@
+use crate::shapes::Shape;
+
+/// An iterator containing the shapes to display
+pub struct CircleShapes;
+
+impl CircleShapes {
+    pub fn new() -> CircleShapes {
+        CircleShapes {}
+    }
+}
+
+impl Iterator for CircleShapes {
+    type Item = Shape;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        None
+    }
+}

src/drawing.rs

@@ -2,14 +2,22 @@ use std::f64;
 use crate::shapes::*;
 
 pub fn draw_circle(circle: Circle, context: &web_sys::CanvasRenderingContext2d) {
-  context.move_to(circle.center.x+circle.radius, circle.center.y);
-  context
-    .arc(circle.center.x, circle.center.y, circle.radius, 0.0, f64::consts::PI * 2.0)
-    .unwrap();
+    context.move_to(circle.center.x+circle.radius, circle.center.y);
+    context
+        .arc(circle.center.x, circle.center.y, circle.radius, 0.0, f64::consts::PI * 2.0)
+        .unwrap();
 }
 
 pub fn draw_line(line: Line, context: &web_sys::CanvasRenderingContext2d) {
-  context.move_to(line.p1.x, line.p1.y);
-  context
-    .line_to(line.p2.x, line.p2.y);
+    context.move_to(line.p1.x, line.p1.y);
+    context
+        .line_to(line.p2.x, line.p2.y);
+}
+
+pub fn draw_shape(shape: Shape, context: &web_sys::CanvasRenderingContext2d) {
+    match shape {
+        Shape::Circle(circle) => draw_circle(circle, context),
+        Shape::Line(line) => draw_line(line, context),
+        Shape::Point(_) => (),
+    }
 }

src/lib.rs

@@ -3,33 +3,40 @@ use wasm_bindgen::JsCast;
 
 mod drawing;
 mod shapes;
+mod circle;
 
 use shapes::*;
+use circle::CircleShapes;
 
 #[wasm_bindgen(start)]
 pub fn start() {
-  let document = web_sys::window().unwrap().document().unwrap();
-  let canvas = document.get_element_by_id("canvas").unwrap();
-  let canvas: web_sys::HtmlCanvasElement = canvas
-      .dyn_into::<web_sys::HtmlCanvasElement>()
-      .map_err(|_| ())
-      .unwrap();
+    let document = web_sys::window().unwrap().document().unwrap();
+    let canvas = document.get_element_by_id("canvas").unwrap();
+    let canvas: web_sys::HtmlCanvasElement = canvas
+        .dyn_into::<web_sys::HtmlCanvasElement>()
+        .map_err(|_| ())
+        .unwrap();
   
-  let context = canvas
-    .get_context("2d")
-    .unwrap()
-    .unwrap()
-    .dyn_into::<web_sys::CanvasRenderingContext2d>()
-    .unwrap();
+    let context = canvas
+        .get_context("2d")
+        .unwrap()
+        .unwrap()
+        .dyn_into::<web_sys::CanvasRenderingContext2d>()
+        .unwrap();
 
-  context.begin_path();
+    context.begin_path();
   
-  drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 70.0}, &context);
-  drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 35.0}, &context);
-  drawing::draw_circle(Circle {center: Point {x: 60.0, y: 65.0}, radius: 5.0}, &context);
+    let iter = CircleShapes::new();
+    for shape in iter {
+        drawing::draw_shape(shape, &context);
+    }
   
-  drawing::draw_line(Line {p1: Point {x: 0.0, y: 0.0}, p2: Point {x: 150.0, y: 150.0}}, &context);
-  drawing::draw_line(Line {p1: Point {x: 0.0, y: 150.0}, p2: Point {x: 150.0, y: 0.0}}, &context);
+    drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 70.0}, &context);
+    drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 35.0}, &context);
+    drawing::draw_circle(Circle {center: Point {x: 60.0, y: 65.0}, radius: 5.0}, &context);
   
-  context.stroke();
+    drawing::draw_line(Line {p1: Point {x: 0.0, y: 0.0}, p2: Point {x: 150.0, y: 150.0}}, &context);
+    drawing::draw_line(Line {p1: Point {x: 0.0, y: 150.0}, p2: Point {x: 150.0, y: 0.0}}, &context);
+  
+    context.stroke();
 }

src/shapes.rs

@@ -12,3 +12,9 @@ pub struct Line {
   pub p1: Point,
   pub p2: Point,
 }
+
+pub enum Shape {
+    Point(Point),
+    Circle(Circle),
+    Line(Line),
+}