show some more code in the workspace

[rust-101.git] / workspace / src / part12.rs

diff --git a/workspace/src/part12.rs b/workspace/src/part12.rs
index a3519957ca7dbfcf0d207f6004c3fa3df909ff1e..86fb4bb14b350f192acb7cb9c2a9ff997c109e59 100644 (file)
--- a/workspace/src/part12.rs
+++ b/workspace/src/part12.rs
@@ -13,7 +13,7 @@ struct Callbacks {
 
 impl Callbacks {
     pub fn new() -> Self {
-        unimplemented!()
+        Callbacks { callbacks: Vec::new() }
     }
 
     // Registration works just like last time, except that we are creating an `Rc` now.
@@ -69,11 +69,10 @@ struct CallbacksMut {
 
 impl CallbacksMut {
     pub fn new() -> Self {
-        unimplemented!()
+        CallbacksMut { callbacks: Vec::new() }
     }
 
     pub fn register<F: FnMut(i32)+'static>(&mut self, callback: F) {
-        let cell = Rc::new(RefCell::new(callback));
         unimplemented!()
     }
 
@@ -104,7 +103,6 @@ fn demo_mut(c: &mut CallbacksMut) {
     c.call(1); c.clone().call(2);
 }
 
-// **Exercise 12.1**: Change the type of `call` to ask only for a shared borrow. Then write some piece of code using only the available, public
-// interface of `CallbacksMut` such that a reentrant call to `call` is happening, and the program aborts because the `RefCell` refuses to hand
-// out a second mutable borrow to its content.
+// **Exercise 12.1**: Write some piece of code using only the available, public interface of `CallbacksMut` such that a reentrant call to a closure
+// is happening, and the program aborts because the `RefCell` refuses to hand out a second mutable borrow of the closure's environment.