Through 1.2.2.1

rustbyexample/01221/src/main.rs

@@ -0,0 +1,23 @@
+use std::fmt;
+
+struct List(Vec<i32>);
+
+impl fmt::Display for List {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let List(ref vec) = *self;
+
+        try!(write!(f, "["));
+
+        for (count, v) in vec.iter().enumerate() {
+            if count != 0 { try!(write!(f, ", ")); }
+            try!(write!(f, "{}", v));
+        }
+
+        write!(f, "]")
+    }
+}
+
+fn main() {
+    let v = List(vec![1, 2, 3]);
+    println!("{}", v);
+}