Changed minimum required rustc version from 1.2 to 1.3.

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

diff --git a/workspace/src/part12.rs b/workspace/src/part12.rs
index 23db4f60e586faa8eca2eb1951b93ef1a30bef69..390b5dfa9530880a48a3feac7997154dcf774184 100644 (file)
--- a/workspace/src/part12.rs
+++ b/workspace/src/part12.rs
@@ -48,7 +48,7 @@ fn demo_cell(c: &mut Callbacks) {
         let count = Cell::new(0);
         // Again, we have to move ownership if the `count` into the environment closure.
         c.register(move |val| {
         let count = Cell::new(0);
         // Again, we have to move ownership if the `count` into the environment closure.
         c.register(move |val| {

-            // In here, all we have is a shared borrow of our environment. But that's good enough for the `get` and `set` of the cell!
+            // In here, all we have is a shared reference of our environment. But that's good enough for the `get` and `set` of the cell!

             let new_count = count.get()+1;
             count.set(new_count);
             println!("Callback 2: {} ({}. time)", val, new_count);
             let new_count = count.get()+1;
             count.set(new_count);
             println!("Callback 2: {} ({}. time)", val, new_count);


@@ -81,7 +81,7 @@ impl CallbacksMut {
             // We have to *explicitly* borrow the contents of a `RefCell` by calling `borrow` or `borrow_mut`.
             let mut closure = callback.borrow_mut();
             // Unfortunately, Rust's auto-dereference of pointers is not clever enough here. We thus have to explicitly
             // We have to *explicitly* borrow the contents of a `RefCell` by calling `borrow` or `borrow_mut`.
             let mut closure = callback.borrow_mut();
             // Unfortunately, Rust's auto-dereference of pointers is not clever enough here. We thus have to explicitly

-            // dereference the smart pointer and obtain a mutable borrow of the content.
+            // dereference the smart pointer and obtain a mutable reference to the content.

             (&mut *closure)(val);
         }
     }
             (&mut *closure)(val);
         }
     }


@@ -103,7 +103,6 @@ fn demo_mut(c: &mut CallbacksMut) {
     c.call(1); c.clone().call(2);
 }
 
     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 panics because the `RefCell` refuses to hand out a second mutable borrow of the closure's environment.