rjwebb · April 11, 2017 22:41 · Apr 11, 2017
diff --git a/linked_list.rs b/linked_list.rs
@@ -0,0 +1,60 @@
+use std::fmt;
+
+/*
+Made this to experiment with making abstract data structures in Rust.
+
+I'm not entirely convinced that it's necessary to use Box here...
+*/
+
+fn flip(p: &Point) -> Point {
+    Point{ x: p.y, y: p.x }
+}
+
+fn map_ll<T, F>(list: &LinkedList<T>, func: F) -> LinkedList<T> where F: Fn(&T) -> T {
+    LinkedList {
+        head: func(&list.head),
+        tail: match list.tail {
+            Some(ref ll) => Some(Box::new(map_ll(&ll, func))),
+            None => None
+        }
+    }
+}
+
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+impl fmt::Display for Point {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "(x: {}, y: {})", self.x, self.y)
+    }
+}
+
+
+struct LinkedList<T> {
+    head: T,
+    tail: Option<Box<LinkedList<T>>>,
+}
+
+impl <T: fmt::Display> fmt::Display for LinkedList<T> {
+    fn fmt(&self, f: &mut fmt:: Formatter) -> fmt::Result {
+        match self.tail {
+            Some(ref ll) => write!(f, "{} -> {}", self.head, ll),
+            None => write!(f, "{}", self.head),
+        }
+    }
+}
+
+
+fn main() {
+    let p = Point { x: 10, y: 20 };
+    let p2 = Point { x: 30, y: 40 };
+
+    let l = LinkedList { head: p, tail: Some(Box::new(LinkedList { head: p2, tail: None })) };
+    let l2 = map_ll(&l, flip);
+
+    println!("linked list: {}", l);
+    println!("linked list (flipped): {}", l2);
+}