add chain

single_file_tests/chain.rs

@@ -0,0 +1,46 @@
+use std::rc::Rc;
+use std::fmt::Display;
+
+enum Node<T> {
+    Nil,
+    Value(T, Rc<Node<T>>),
+}
+
+fn build_chain_str() -> Node<String> {
+    let mut chain = Node::<String>::Nil;
+    for &n in &["Tom", "Jerry", "Mike"] {
+        let node = Node::<String>::Value(n.into(), Rc::new(chain));
+        chain = node;
+    }
+    chain
+}
+
+fn build_chain_usize() -> Node<usize> {
+    let mut chain = Node::<usize>::Nil;
+    for &n in &[1, 2, 3, 4, 5] {
+        let node = Node::<usize>::Value(n, Rc::new(chain));
+        chain = node;
+    }
+    chain
+}
+
+fn print_chain<T>(chain: &Node<T>) where T: Display {
+    let mut ptr = chain;
+    while let Node::Value(n, next) = ptr {
+        print!("{}", n);
+        ptr = next;
+
+        if let &Node::<T>::Value(_, _) = ptr {
+            print!(" -> ");
+        }
+    }
+    println!();
+}
+
+fn main() {
+    let chain = build_chain_str();
+    print_chain(&chain);
+
+    let chain_usize = build_chain_usize();
+    print_chain(&chain_usize);
+}