editable playground

book.toml

@@ -15,3 +15,6 @@ create-missing = false
 [output.html]
 default-theme = "navy"
 mathjax-support = true
+
+[output.html.playground]
+editable = true

src/exercises/bind.md

@@ -1,6 +1,7 @@
+Make this compile and pass tests.
 ```rust
 # mod __ {
-fn bind<T, F: FnOnce(T) -> Option<T>>(f: F, fa: Option<T>) -> Option<T> {
+fn bind<T, F: Fn(T) -> Option<T>>(f: F, fa: Option<T>) -> Option<T> {
     match fa {
         Some(a) => f(a),
         None => None,
@@ -25,3 +26,29 @@ assert_eq!(
     Some("banana".to_string()),
 );
 ```
+
+Try solving it in the playground:
+```rust,editable,compile_fail
+fn bind<T, F: Fn(T) -> Option<T>>(f: F, fa: Option<T>) -> Option<T> {
+    match fa {
+        Some(a) => f(a),
+        None => None,
+    }
+}
+
+fn main() {
+    assert_eq!(bind(|x: i32| Some(x + 3), Some(2)), Some(5));
+    assert_eq!(bind(|x: i32| Some(x + 3), None), None);
+    assert_eq!(bind(|_: i32| None, Some(2)), None);
+    assert_eq!(bind(|_: i32| None, None), None);
+
+    assert_eq!(bind(|x: &str| Some(x), Some("apple")), Some("apple"));
+    assert_eq!(bind(|_: &str| Some("banana"), Some("apple")), Some("banana"));
+
+    let banana = "banana".to_string();
+    assert_eq!(
+        bind(|_: String| Some(banana), Some("apple".to_string())),
+        Some("banana".to_string()),
+    );
+}
+```

src/exercises/refbind.md

@@ -1,3 +1,4 @@
+Make this compile and pass tests.
 ```rust
 # mod __ {
 fn refbind<T, F: Fn(&T) -> Option<&T>>(f: F, fa: Option<&T>) -> Option<&T> {
@@ -24,3 +25,29 @@ assert_eq!(
     Some(banana)
 );
 ```
+
+Try solving it in the playground:
+```rust,editable,compile_fail
+fn refbind<T, F: Fn(&T) -> Option<&T>>(f: F, fa: Option<&T>) -> Option<&T> {
+    match fa {
+        Some(a) => f(a),
+        None => None,
+    }
+}
+
+fn main() {
+    let apple = "apple".to_string();
+    let banana = "banana".to_string();
+    assert_eq!(
+        refbind(|_: &String| Some(&banana), Some(&apple)),
+        Some(&banana)
+    );
+
+    let banana = "banana";
+    assert_eq!(
+        refbind(|_: &str| Some(banana), Some("apple")),
+        Some(banana)
+    );
+}
+```
+