finalize part 11

[rust-101.git] / workspace / src / part11.rs

diff --git a/workspace/src/part11.rs b/workspace/src/part11.rs
index f868a3c05394548317b4f36e3bb71e863539efa0..01f170b40ce7b34d41a2c39c11e6d32ca40e6f07 100644 (file)
--- a/workspace/src/part11.rs
+++ b/workspace/src/part11.rs
@@ -1,9 +1,8 @@
-// Rust-101, Part 11: Trait Objects, Box (WIP)
-// ===========================================
-
+// Rust-101, Part 11: Trait Objects, Box, Rc
+// =========================================
 
 mod callbacks {
-    // For now, we just decide that the callbakcs have an argument of type `i32`.
+    // For now, we just decide that the callbacks have an argument of type `i32`.
     struct CallbacksV1<F: FnMut(i32)> {
         callbacks: Vec<F>,
     }
@@ -12,23 +11,23 @@ mod callbacks {
         callbacks: Vec<FnMut(i32)>,
     } */
 
-    struct Callbacks {
+    pub struct Callbacks {
         callbacks: Vec<Box<FnMut(i32)>>,
     }
 
     impl Callbacks {
         // Now we can provide some functions. The constructor should be straight-forward.
-        fn new() -> Self {
+        pub fn new() -> Self {
             unimplemented!()
         }
 
         // Registration simply stores the callback.
-        fn register(&mut self, callback: Box<FnMut(i32)>) {
+        pub fn register(&mut self, callback: Box<FnMut(i32)>) {
             unimplemented!()
         }
 
         // And here we call all the stored callbacks.
-        fn call(&mut self, val: i32) {
+        pub fn call(&mut self, val: i32) {
             // Since they are of type `FnMut`, we need to mutably iterate. Notice that boxes dereference implicitly.
             for callback in self.callbacks.iter_mut() {
                 unimplemented!()
@@ -36,47 +35,45 @@ mod callbacks {
         }
     }
 
-    // Now we are read for the demo.
-    pub fn demo() {
-        let mut c = Callbacks::new();
+    // Now we are ready for the demo.
+    pub fn demo(c: &mut Callbacks) {
         c.register(Box::new(|val| println!("Callback 1: {}", val)));
-
         c.call(0);
 
         let mut count: usize = 0;
         c.register(Box::new(move |val| { count = count+1; println!("Callback 2, {}. time: {}", count, val); } ));
-        c.call(1);
-        c.call(2);
+        c.call(1); c.call(2);
     }
-
 }
 
 // Remember to edit `main.rs` to run the demo.
 pub fn main() {
-    callbacks::demo();
+    let mut c = callbacks::Callbacks::new();
+    callbacks::demo(&mut c);
 }
 
 mod callbacks_clone {
 
-    use std::rc;
+    use std::rc::Rc;
 
     #[derive(Clone)]
-    struct Callbacks {
-        callbacks: Vec<rc::Rc<Fn(i32)>>,
+    pub struct Callbacks {
+        callbacks: Vec<Rc<Fn(i32)>>,
     }
 
-    // The methods on these clonable callbacks are just like the ones above.
     impl Callbacks {
-        fn new() -> Self {
+        pub fn new() -> Self {
             unimplemented!()
         }
 
-        fn register(&mut self, callback: rc::Rc<Fn(i32)>) {
+        // For the `register` function, we don't actually have to use trait objects in the argument.
+        
+        pub fn register<F: Fn(i32)+'static>(&mut self, callback: F) {
             unimplemented!()
         }
 
-        fn call(&mut self, val: i32) {
-            // We only need a shared iterator here. `Rc` also implicitly dereferences, so we can just call the callback.
+        pub fn call(&mut self, val: i32) {
+            // We only need a shared iterator here. `Rc` also implicitly dereferences, so we can simply call the callback.
             for callback in self.callbacks.iter() {
                 unimplemented!()
             }
@@ -84,12 +81,9 @@ mod callbacks_clone {
     }
 
     // The demo works just as above. Our counting callback doesn't work anymore though, because we are using `Fn` now.
-    fn demo() {
-        let mut c = Callbacks::new();
-        c.register(rc::Rc::new(|val| println!("Callback 1: {}", val)));
-
-        c.call(0);
-        c.call(1);
+    fn demo(c: &mut Callbacks) {
+        c.register(|val| println!("Callback 1: {}", val));
+        c.call(0); c.call(1);
     }
 }
 
@@ -97,3 +91,4 @@ mod callbacks_clone {
 // to work with an arbitrary type `T` that's passed to the callbacks. Since you need to call multiple callbacks with the
 // same `t: T`, you will either have to restrict `T` to `Copy` types, or pass a borrow.
 
+