After a few hints on IRC I managed to simplify it to:
fn collect_node_names(&self, map: &mut HashMap<String, Gc<node::Node>>,
nodes: &Vec<Gc<node::Node>>) -> bool {
for n in nodes.iter() {
if !self.collect_node_names(map, &n.subnodes) {
return false;
}
match n.name {
Some(ref name) => {
if map.contains_key(name) {
self.sess.span_diagnostic.span_err(n.name_span, format!(
"duplicate `{}` definition", name).as_slice());
self.sess.span_diagnostic.span_warn(
map.get(name).name_span,
"previously defined here");
return false;
} else {
map.insert(name.clone(), *n);
}
},
None => (),
}
}
true
}
My failure point was that I didn't realise you cannot access &mut while yo
have a reference to anything you pass &mut to.
On Sun, Jun 15, 2014 at 8:14 AM, Vladimir Pouzanov <[email protected]>
wrote:
> I have a tree of Nodes where each node might have a name. I'm trying to
> convert the tree into a HashMap of named nodes, but my code is getting
> extremely complex due to the fact that I cannot pass &mut HashMap around.
>
> let mut named_nodes = HashMap::new();
> let nodes = vec!( ... );
> named_nodes = self.collect_node_names(&named_nodes, &nodes);
> println!('{}', named_nodes);
>
> fn collect_node_names(&self, map: &HashMap<String, Gc<node::Node>>,
> nodes: &Vec<Gc<node::Node>>) -> HashMap<String, Gc<node::Node>> {
> let mut local_map: HashMap<String, Gc<node::Node>> = HashMap::new();
> for (k,v) in map.iter() {
> local_map.insert(k.clone(), *v);
> }
> for n in nodes.iter() {
> for (k,v) in self.collect_node_names(&local_map, &n.subnodes).iter() {
> local_map.insert(k.clone(), *v);
> }
> match n.name {
> Some(ref name) => {
> if local_map.contains_key(name) {
>
> } else {
> local_map.insert(name.clone(), *n);
> }
> },
> None => (),
> }
> }
> local_map
> }
>
> this one works, but it's bloated and slow. Any hints on how to improve the
> code?
>
> --
> Sincerely,
> Vladimir "Farcaller" Pouzanov
> http://farcaller.net/
>
--
Sincerely,
Vladimir "Farcaller" Pouzanov
http://farcaller.net/
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