tree.rs

use std::cmp::Ordering;

enum Tree<T: Ord> {
	  Node {v: T, left: Box<Tree<T>>, right: Box<Tree<T>>},
	  Empty,
}

impl<T: Ord> Tree<T> {

	  fn find(&self, target: T) -> bool {
		    match self {
			      &Tree::Node { v, ref left, ref right } => {
                if target == v { true }
                else if target < v { right.find(target) }
                else { left.find(target) }
				    },
			      &Tree::Empty => false,
		    }
    }
    
	  fn empty() -> Tree<T> {
		    Tree::Empty
	  }


	  fn insert(&mut self, nv: T) {
		    match self {
			      &mut Tree::Node { ref v, ref mut left, ref mut right } => {
				        match nv.cmp(v) {
					          Ordering::Less => right.insert(nv),
					          Ordering::Greater => left.insert(nv),
					          Ordering::Equal  => return
				        }
			      },
			      &mut Tree::Empty => {
				        *self = Tree::Node {
                    v: nv,
                    left: Box::new(Tree::Empty),
                    right: Box::new(Tree::Empty)
                }
			      },
		    };
	  }

	  fn is_empty(&self) -> bool {
		    match self {
			      &Tree::Node { .. } => false,
			      &Tree::Empty => true,
		    }
	  }

}