btree.rs

/*
rustc -O -L. --test -o btree btree.rs
btree.rs:68:24: 79:7 error: mismatched types: expected `~[~str]` but found `std::iterator::MapIterator<,&std::option::Option<TreeItem<T,U>>,~(),std::vec::VecIterator<,std::option::Option<TreeItem<T,U>>>>` (expected vector but found struct std::iterator::MapIterator)
btree.rs:68     let buf : ~[~str] = tree.nodes.iter().transform(|x| {
btree.rs:69         ~"\t".repeat(indent).push_str(match *x {
btree.rs:70             Some(TreeNode { key: k, value: tree }) => {
btree.rs:71                 let buf = ~"Node(key=...)\n";
btree.rs:72                 buf //buf.push_str(tree.to_str())
btree.rs:73             }
            ...
*/

impl<K: ToStr, V> ToStr for BTree<K, V> {
    fn to_str(&self) -> ~str { to_str(self, 0) }
}

fn to_str<K: ToStr, V>(tree: &mut BTree<K, V>, indent: uint) -> ~str {
    let buf : ~[~str] = tree.nodes.iter().transform(|x| {
        "\t".repeat(indent) + match *x {
            Some(TreeNode { key: k, value: tree }) => {
                let buf = ~"Node(key=...)\n";
                buf //buf.push_str(tree.to_str())
            }
            Some(TreeLeaf { key: k, value: _ }) => {
                fmt!("Leaf(key=%s)", k.to_str())
            }
            None => ~"None",
        }
    }).collect();

    buf.connect("\n")
}