concepts: Add alternative Post implementation with states as types

[learn-rust.git] / concepts / src / main.rs

diff --git a/concepts/src/main.rs b/concepts/src/main.rs
index 65fb785c838a2a966e6c1d4c5494f4751d5f0b0d..4b6df6447be9930e5773202f24601cd817722eb8 100644 (file)
--- a/concepts/src/main.rs
+++ b/concepts/src/main.rs
@@ -205,6 +205,7 @@ fn test_threads() {
 
     t1.join().unwrap();
 
+    // message passing
     let (tx1, rx) = sync::mpsc::channel();
     let tx2 = tx1.clone();
 
@@ -228,6 +229,58 @@ fn test_threads() {
 
     sender1.join().unwrap();
     sender2.join().unwrap();
+
+    // shared state
+    let counter = sync::Arc::new(sync::Mutex::new(0));
+    let mut threads = vec![];
+    for _ in 0..10 {
+        let tc = sync::Arc::clone(&counter);
+        threads.push(thread::spawn(move || {
+            *tc.lock().unwrap() += 1;
+        }));
+    }
+
+    for t in threads {
+        t.join().unwrap();
+    }
+
+    println!("counter: {}", *counter.lock().unwrap());
+}
+
+fn test_dyn_traits() {
+    let text = "I ate a salad for lunch today";
+    let mut post = Post::new();
+    post.add_text(text);
+    assert_eq!("", post.content());
+
+    post.request_review();
+    assert_eq!("", post.content());
+
+    post.reject();
+    assert_eq!("", post.content());
+
+    post.request_review();
+    assert_eq!("", post.content());
+
+    post.approve();  // first
+    assert_eq!("", post.content());
+
+    post.approve();  // second
+    assert_eq!(text, post.content());
+
+    post.reject();  // no-op
+    assert_eq!(text, post.content());
+}
+
+fn test_state_types() {
+    let mut post = TPost::new();
+    post.add_text("I ate a salad for lunch");
+    let post = post.request_review();
+    let mut post = post.reject();
+    post.add_text(" today");
+    let post = post.request_review();
+    let post = post.approve();
+    assert_eq!(post.content(), "I ate a salad for lunch today");
 }
 
 fn main() {
@@ -239,4 +292,6 @@ fn main() {
     test_closures();
     test_iterators();
     test_threads();
+    test_dyn_traits();
+    test_state_types();
 }