gistfile1.rs

// This is the initial idea: a graph structure that is a hash containing a vector of target node and edge properties
// Doesn’t compile with
// src/graph.rs:56:32: 56:37 error: cannot move out of dereference of `&`-pointer
// src/graph.rs:56             Some(list) => for &(n,e) in list.iter() {

trait Graph<Node, Edge> {
    fn children(&self, &Node, |Node, Edge| -> ()); // iterate on outgoing edges
}

impl<N:Hash+Eq,E> Graph<N,E> for HashMap<N, ~[(N,E)]> {
    fn children(&self, out_node: &N, f : |N, E| -> ()) {
        match self.find(out_node) {
            None => (),
            Some(list) => for &(n,e) in list.iter() {
//             Some(list) => for n in list.iter() {
// works, but how could I directly match on the tuple?
                println!("{:?}, {:?}", n, e);
                // f(n,e);
            }
        };
    }
}

// Just to play arround I tried the following that worked as I expected it
extern crate collections;
use collections::HashMap;

fn main() {
    let mut g = HashMap::new();
    let v = ~[(1,2), (3,4)];
    g.insert(~"foo", v);

    match g.find(&~"foo") {
        None => println!("Missing"),
        Some(vec) => for &(a,b) in vec.iter() {
            println!("{:?}, {:?}", a, b);
        }
    }
}