Cargo.lock

@@ -2503,6 +2503,16 @@ dependencies = [
  "version_check 0.9.4",
 ]
 
+[[package]]
+name = "nary_tree"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fb86edb8951cb3852cbb33ef558650e9f18c9d2e7fd79a6849c984a3825719c7"
+dependencies = [
+ "slab",
+ "snowflake",
+]
+
 [[package]]
 name = "native-tls"
 version = "0.2.11"
@@ -2705,6 +2715,7 @@ dependencies = [
  "config-derive",
  "cool_asserts",
  "grid",
+ "nary_tree",
  "serde 1.0.193",
  "serde_json",
  "sgf",
@@ -3685,6 +3696,7 @@ version = "0.1.0"
 dependencies = [
  "chrono",
  "cool_asserts",
+ "nary_tree",
  "nom",
  "serde 1.0.193",
  "thiserror",
@@ -3766,6 +3778,12 @@ version = "1.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4dccd0940a2dcdf68d092b8cbab7dc0ad8fa938bf95787e1b916b0e3d0e8e970"
 
+[[package]]
+name = "snowflake"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27207bb65232eda1f588cf46db2fee75c0808d557f6b3cf19a75f5d6d7c94df1"
+
 [[package]]
 name = "socket2"
 version = "0.4.10"

Cargo.nix

@@ -7917,6 +7917,28 @@ rec {
         };
         resolvedDefaultFeatures = [ "default" ];
       };
+      "nary_tree" = rec {
+        crateName = "nary_tree";
+        version = "0.4.3";
+        edition = "2021";
+        sha256 = "1iqray1a716995l9mmvz5sfqrwg9a235bvrkpcn8bcqwjnwfv1pv";
+        authors = [
+          "Ian <iwburns8@gmail.com>"
+          "David Cohen <dacohen@pm.me>"
+        ];
+        dependencies = [
+          {
+            name = "slab";
+            packageId = "slab";
+          }
+          {
+            name = "snowflake";
+            packageId = "snowflake";
+          }
+        ];
+        features = {
+        };
+      };
       "native-tls" = rec {
         crateName = "native-tls";
         version = "0.2.11";
@@ -8551,6 +8573,10 @@ rec {
             name = "grid";
             packageId = "grid";
           }
+          {
+            name = "nary_tree";
+            packageId = "nary_tree";
+          }
           {
             name = "serde";
             packageId = "serde 1.0.193";
@@ -11570,6 +11596,10 @@ rec {
             packageId = "chrono";
             features = [ "serde" ];
           }
+          {
+            name = "nary_tree";
+            packageId = "nary_tree";
+          }
           {
             name = "nom";
             packageId = "nom";
@@ -11803,6 +11833,21 @@ rec {
         };
         resolvedDefaultFeatures = [ "const_generics" "const_new" "union" ];
       };
+      "snowflake" = rec {
+        crateName = "snowflake";
+        version = "1.3.0";
+        edition = "2015";
+        sha256 = "1wadr7bxdxbmkbqkqsvzan6q1h3mxqpxningi3ss3v9jaav7n817";
+        authors = [
+          "Steven Allen <steven@stebalien.com>"
+        ];
+        features = {
+          "serde" = [ "dep:serde" ];
+          "serde_derive" = [ "dep:serde_derive" ];
+          "serde_support" = [ "serde" "serde_derive" ];
+        };
+        resolvedDefaultFeatures = [ "default" ];
+      };
       "socket2 0.4.10" = rec {
         crateName = "socket2";
         version = "0.4.10";

crate-hashes.json

@@ -223,6 +223,7 @@
   "registry+https://github.com/rust-lang/crates.io-index#mio@0.8.10": "02gyaxvaia9zzi4drrw59k9s0j6pa5d1y2kv7iplwjipdqlhngcg",
   "registry+https://github.com/rust-lang/crates.io-index#modifier@0.1.0": "0n3fmgli1nsskl0whrfzm1gk0rmwwl6pw1q4nb9sqqmn5h8wkxa1",
   "registry+https://github.com/rust-lang/crates.io-index#multer@2.1.0": "1hjiphaypj3phqaj5igrzcia9xfmf4rr4ddigbh8zzb96k1bvb01",
+  "registry+https://github.com/rust-lang/crates.io-index#nary_tree@0.4.3": "1iqray1a716995l9mmvz5sfqrwg9a235bvrkpcn8bcqwjnwfv1pv",
   "registry+https://github.com/rust-lang/crates.io-index#native-tls@0.2.11": "0bmrlg0fmzxaycjpkgkchi93av07v2yf9k33gc12ca9gqdrn28h7",
   "registry+https://github.com/rust-lang/crates.io-index#nix@0.27.1": "0ly0kkmij5f0sqz35lx9czlbk6zpihb7yh1bsy4irzwfd2f4xc1f",
   "registry+https://github.com/rust-lang/crates.io-index#no-std-compat@0.4.1": "132vrf710zsdp40yp1z3kgc2ss8pi0z4gmihsz3y7hl4dpd56f5r",
@@ -342,6 +343,7 @@
   "registry+https://github.com/rust-lang/crates.io-index#siphasher@0.3.11": "03axamhmwsrmh0psdw3gf7c0zc4fyl5yjxfifz9qfka6yhkqid9q",
   "registry+https://github.com/rust-lang/crates.io-index#slab@0.4.9": "0rxvsgir0qw5lkycrqgb1cxsvxzjv9bmx73bk5y42svnzfba94lg",
   "registry+https://github.com/rust-lang/crates.io-index#smallvec@1.11.2": "0w79x38f7c0np7hqfmzrif9zmn0avjvvm31b166zdk9d1aad1k2d",
+  "registry+https://github.com/rust-lang/crates.io-index#snowflake@1.3.0": "1wadr7bxdxbmkbqkqsvzan6q1h3mxqpxningi3ss3v9jaav7n817",
   "registry+https://github.com/rust-lang/crates.io-index#socket2@0.4.10": "03ack54dxhgfifzsj14k7qa3r5c9wqy3v6mqhlim99cc03y1cycz",
   "registry+https://github.com/rust-lang/crates.io-index#socket2@0.5.5": "1sgq315f1njky114ip7wcy83qlphv9qclprfjwvxcpfblmcsqpvv",
   "registry+https://github.com/rust-lang/crates.io-index#spin@0.5.2": "0b84m6dbzrwf2kxylnw82d3dr8w06av7rfkr8s85fb5f43rwyqvf",

otg/core/Cargo.toml

@@ -14,6 +14,7 @@ sgf             = { path = "../../sgf" }
 grid            = { version = "0.9" }
 serde_json      = { version = "1" }
 serde           = { version = "1", features = [ "derive" ] }
+nary_tree       = { version = "0.4" }
 thiserror       = { version = "1" }
 uuid            = { version = "0.8", features = ["v4", "serde"] }
 

otg/core/src/api.rs

@@ -81,7 +81,7 @@ impl From<HotseatPlayerRequest> for Player {
 }
 */
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug)]
 pub enum CoreResponse {
     Library(library::LibraryResponse),
     Settings(settings::SettingsResponse),

otg/core/src/database.rs

@@ -42,7 +42,8 @@ impl Database {
                             .unwrap();
                         match parse_sgf(&buffer) {
                             Ok(sgfs) => {
-                                let mut sgfs = sgfs.into_iter().flatten().collect::<Vec<sgf::GameRecord>>();
+                                let mut sgfs =
+                                    sgfs.into_iter().flatten().collect::<Vec<sgf::GameRecord>>();
                                 games.append(&mut sgfs);
                             }
                             Err(err) => println!("Error parsing {:?}: {:?}", entry.path(), err),

otg/core/src/lib.rs

@@ -29,5 +29,6 @@ pub mod library;
 pub mod settings;
 
 mod types;
-pub use types::{BoardError, Color, Config, ConfigOption, LibraryPath, Player, Rank, Size, Tree};
+pub use types::{
-
+    BoardError, Color, Config, ConfigOption, DepthTree, LibraryPath, Player, Rank, Size,
+};

otg/core/src/library.rs

@@ -14,18 +14,18 @@ General Public License for more details.
 You should have received a copy of the GNU General Public License along with On the Grid. If not, see <https://www.gnu.org/licenses/>.
 */
 
-use crate::{Core};
+use crate::Core;
 use serde::{Deserialize, Serialize};
 use sgf::GameRecord;
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub enum LibraryRequest {
-    ListGames
+    ListGames,
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug)]
 pub enum LibraryResponse {
-    Games(Vec<GameRecord>)
+    Games(Vec<GameRecord>),
 }
 
 async fn handle_list_games(model: &Core) -> LibraryResponse {
@@ -39,10 +39,8 @@ async fn handle_list_games(model: &Core) -> LibraryResponse {
     }
 }
 
-
 pub async fn handle(model: &Core, request: LibraryRequest) -> LibraryResponse {
     match request {
         LibraryRequest::ListGames => handle_list_games(model).await,
     }
 }
-

otg/core/src/types.rs

@@ -2,10 +2,11 @@ use crate::goban::{Coordinate, Goban};
 use config::define_config;
 use config_derive::ConfigOption;
 use serde::{Deserialize, Serialize};
-use sgf::GameNode;
+use sgf::GameTree;
-use std::{cell::RefCell, collections::VecDeque, fmt, path::PathBuf, time::Duration};
+use std::{
+    collections::{HashMap, VecDeque}, fmt, ops::Deref, path::PathBuf, time::Duration
+};
 use thiserror::Error;
-use uuid::Uuid;
 
 define_config! {
     LibraryPath(LibraryPath),
@@ -229,6 +230,7 @@ impl GameState {
     }
 }
 
+/*
 // To properly generate a tree, I need to know how deep to go. Then I can backtrace. Each node
 // needs to have a depth. Given a tree, the depth of the node is just the distance from the root.
 // This seems obvious, but I had to write it to discover how important that fact was.
@@ -238,19 +240,49 @@ impl GameState {
 pub struct Tree<T> {
     nodes: Vec<Node<T>>,
 }
+*/
 
-#[derive(Debug)]
+pub struct DepthTree(nary_tree::Tree<SizeNode>);
-pub struct Node<T> {
+
-    pub id: usize,
+impl Deref for DepthTree {
-    node: T,
+    type Target = nary_tree::Tree<SizeNode>;
-    parent: Option<usize>,
+
-    depth: usize,
+    fn deref(&self) -> &Self::Target {
-    width: RefCell<Option<usize>>,
+        &self.0
-    children: Vec<usize>,
+    }
 }
 
-impl<T> Tree<T> {
+#[derive(Debug)]
-    fn new(root: T) -> Self {
+pub struct SizeNode {
+    /// Use this to map back to the node in the original game tree. This way we know how to
+    /// correspond from a node in the review tree back to there.
+    #[allow(dead_code)]
+    game_node_id: nary_tree::NodeId,
+
+    /// How deep into the tree is this node?
+    depth: usize,
+
+    /// How far from the leftmost margin is this node?
+    width: usize,
+}
+
+impl SizeNode {
+    pub fn position(&self) -> (usize, usize) {
+        (self.depth, self.width)
+    }
+}
+
+impl DepthTree {
+    // My previous work to convert from a node tree to this tree-with-width dependend on the node tree
+    // being a recursive data structure. Now I need to find a way to convert a slab tree to this width
+    // tree.
+    //
+    // It all feels like a lot of custom weirdness. I shouldn't need a bunch of custom data structures,
+    // so I want to eliminate the "Tree" above and keep using the slab tree. I think I should be able
+    // to build these Node objects without needing a custom data structure.
+    fn new() -> Self {
+        Self(nary_tree::Tree::new())
+        /*
         Tree {
             nodes: vec![Node {
                 id: 0,
@@ -261,8 +293,10 @@ impl<T> Tree<T> {
                 children: vec![],
             }],
         }
+        */
     }
 
+    /*
     pub fn node(&self, idx: usize) -> &T {
         &self.nodes[idx].node
     }
@@ -286,12 +320,21 @@ impl<T> Tree<T> {
         parent.children.push(next_idx);
         next_idx
     }
+    */
 
     pub fn max_depth(&self) -> usize {
-        self.nodes.iter().fold(
+        self.0
-            0,
+            .root()
-            |max, node| if node.depth > max { node.depth } else { max },
+            .unwrap()
-        )
+            .traverse_pre_order()
+            .fold(0, |max, node| {
+                println!("node depth: {}", node.data().depth);
+                if node.data().depth > max {
+                    node.data().depth
+                } else {
+                    max
+                }
+            })
     }
 
     // Since I know the width of a node, now I want to figure out its placement in the larger
@@ -309,7 +352,9 @@ impl<T> Tree<T> {
     // amounts to the position of the parent node.
     //
     // When drawing nodes, I don't know how to persist the level of indent.
-    pub fn position(&self, idx: usize) -> (usize, usize) {
+
+        // unimplemented!()
+        /*
         let node = &self.nodes[idx];
         match node.parent {
             Some(parent_idx) => {
@@ -326,8 +371,9 @@ impl<T> Tree<T> {
             // Root nodes won't have a parent, so just put them in the first column
             None => (0, 0),
         }
-    }
+        */
 
+    /*
     // Given a node, do a postorder traversal to figure out the width of the node based on all of
     // its children. This is equivalent to the widest of all of its children at all depths.
     //
@@ -353,14 +399,100 @@ impl<T> Tree<T> {
 
         width
     }
+    */
 
-    pub fn bfs_iter(&self) -> BFSIter<T> {
+    pub fn bfs_iter(&self) -> BFSIter<'_, SizeNode> {
         let mut queue = VecDeque::new();
-        queue.push_back(&self.nodes[0]);
+        queue.push_back(self.0.root().unwrap());
-        BFSIter { tree: self, queue }
+        BFSIter { queue }
     }
 }
 
+impl<'a> From<&'a GameTree> for DepthTree {
+    fn from(tree: &'a GameTree) -> Self {
+        // Like in the conversion from SGF to GameTree, I need to traverse the entire tree one node
+        // at a time, keeping track of node ids as we go. I'm going to go with a depth-first
+        // traversal. When generating each node, I think I want to generate all of the details of
+        // the node as we go.
+        let source_root_node = tree.root();
+        match source_root_node {
+            Some(source_root_node) => {
+                // Do the real work
+                // The id_map indexes from the source tree to the destination tree. Reverse
+                // indexing is accomplished by looking at the node_id in a node in the destination
+                // tree.
+                let mut id_map: HashMap<nary_tree::NodeId, nary_tree::NodeId> = HashMap::new();
+                let mut tree = nary_tree::Tree::new();
+
+                let mut iter = source_root_node.traverse_pre_order();
+                let _ = iter.next().unwrap(); // we already know that the first element to be
+                                              // returned is the root node, and that the root node
+                                              // already exists. Otherwise we wouldn't even be in
+                                              // this branch.
+
+                let dest_root_id = tree.set_root(SizeNode {
+                    game_node_id: source_root_node.node_id(),
+                    depth: 0,
+                    width: 0,
+                });
+
+                id_map.insert(source_root_node.node_id(), dest_root_id);
+
+                for source_node in iter {
+                    let dest_parent_id = id_map
+                        .get(&source_node.parent().unwrap().node_id())
+                        .unwrap();
+
+                    let mut dest_parent = tree.get_mut(*dest_parent_id).unwrap();
+
+                    let new_depth_node = SizeNode {
+                        game_node_id: source_node.node_id(),
+                        depth: 1 + dest_parent.data().depth,
+                        width: dest_parent.data().width,
+                    };
+
+                    let new_node_id = dest_parent.append(new_depth_node).node_id();
+
+                    match tree
+                        .get(new_node_id)
+                        .unwrap()
+                        .prev_sibling()
+                        .map(|node| node.data().width)
+                    {
+                        None => {}
+                        Some(previous_width) => {
+                            let mut new_node = tree.get_mut(new_node_id).unwrap();
+                            new_node.data().width = previous_width + 1;
+                        }
+                    }
+
+                    /*
+                    let new_node = tree.get_mut(*dest_parent_id).unwrap().append(new_depth_node);
+                    let previous_node = new_node.prev_sibling();
+
+                    match previous_node {
+                        None => {}
+                    }
+                    */
+
+                    /*
+                    match dest_noderef.prev_sibling() {
+                        None => {}
+                        Some(mut node) => { dest_noderef.data().width = node.data().width + 1 }
+                    }
+                    */
+
+                    id_map.insert(source_node.node_id(), new_node_id);
+                }
+
+                Self(tree)
+            }
+            None => Self::new(),
+        }
+    }
+}
+
+/*
 impl<'a> From<&'a GameNode> for Tree<Uuid> {
     fn from(root: &'a GameNode) -> Self {
         fn add_subtree(tree: &mut Tree<Uuid>, parent_idx: usize, node: &GameNode) {
@@ -390,32 +522,31 @@ impl<'a> From<&'a GameNode> for Tree<Uuid> {
         tree
     }
 }
+*/
 
 pub struct BFSIter<'a, T> {
-    tree: &'a Tree<T>,
+    queue: VecDeque<nary_tree::NodeRef<'a, T>>,
-    queue: VecDeque<&'a Node<T>>,
 }
 
 impl<'a, T> Iterator for BFSIter<'a, T> {
-    type Item = &'a Node<T>;
+    type Item = &'a T;
 
     fn next(&mut self) -> Option<Self::Item> {
         let retval = self.queue.pop_front();
-        if let Some(retval) = retval {
+        if let Some(ref retval) = retval {
             retval
-                .children
+                .children()
-                .iter()
+                .for_each(|noderef| self.queue.push_back(noderef));
-                .for_each(|idx| self.queue.push_back(&self.tree.nodes[*idx]));
         }
-        retval
+        retval.map(|retval| retval.data())
     }
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
-    use cool_asserts::assert_matches;
+    // use sgf::{GameRecord, GameTree, GameType, Move, MoveNode};
-    use sgf::{Move, MoveNode};
+    use sgf::{GameNode, GameTree, Move, MoveNode};
 
     #[test]
     fn current_player_changes_after_move() {
@@ -474,80 +605,138 @@ mod test {
     // B G   H
     // C     I
     // D E F
+    fn branching_tree() -> GameTree {
+        let mut game_tree = GameTree::default();
+        let node_a = game_tree.set_root(GameNode::MoveNode(MoveNode::new(
+            sgf::Color::Black,
+            Move::Move("dp".to_owned()),
+        )));
+
+        let node_b = game_tree
+            .get_mut(node_a)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_c = game_tree
+            .get_mut(node_b)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_d = game_tree
+            .get_mut(node_c)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_e = game_tree
+            .get_mut(node_c)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_f = game_tree
+            .get_mut(node_c)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_g = game_tree
+            .get_mut(node_a)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let node_h = game_tree
+            .get_mut(node_a)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        let _ = game_tree
+            .get_mut(node_h)
+            .unwrap()
+            .append(GameNode::MoveNode(MoveNode::new(
+                sgf::Color::Black,
+                Move::Move("dp".to_owned()),
+            )))
+            .node_id();
+
+        game_tree
+    }
+
     #[test]
     fn it_can_calculate_depth_from_game_tree() {
-        let mut node_a = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        let game_tree = branching_tree();
-        let mut node_b = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        let tree = DepthTree::from(&game_tree);
-        let mut node_c = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        assert_eq!(
-        let node_d = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+            game_tree.root().unwrap().traverse_pre_order().count(),
-        let node_e = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+            tree.0.root().unwrap().traverse_pre_order().count()
-        let node_f = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        );
-        let node_g = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let mut node_h = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_i = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-
-        node_c.children.push(GameNode::MoveNode(node_d));
-        node_c.children.push(GameNode::MoveNode(node_e));
-        node_c.children.push(GameNode::MoveNode(node_f));
-
-        node_b.children.push(GameNode::MoveNode(node_c));
-
-        node_h.children.push(GameNode::MoveNode(node_i));
-
-        node_a.children.push(GameNode::MoveNode(node_b));
-        node_a.children.push(GameNode::MoveNode(node_g));
-        node_a.children.push(GameNode::MoveNode(node_h));
-
-        let game_tree = GameNode::MoveNode(node_a);
-
-        let tree = Tree::from(&game_tree);
-
         assert_eq!(tree.max_depth(), 3);
     }
 
-    // A
-    // B G   H
-    // C     I
-    // D E F
     #[test]
     fn it_calculates_horizontal_position_of_nodes() {
-        let mut node_a = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        let game_tree = branching_tree();
-        let mut node_b = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
+        let tree = DepthTree::from(&game_tree);
-        let mut node_c = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_d = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_e = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_f = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_g = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let mut node_h = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
-        let node_i = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
 
-        node_c.children.push(GameNode::MoveNode(node_d));
+        let node_a = tree.root().unwrap();
-        node_c.children.push(GameNode::MoveNode(node_e));
+        assert_eq!(node_a.data().position(), (0, 0));
-        node_c.children.push(GameNode::MoveNode(node_f));
 
-        node_b.children.push(GameNode::MoveNode(node_c));
+        let node_b = node_a.first_child().unwrap();
+        assert_eq!(node_b.data().position(), (1, 0));
+        let node_g = node_b.next_sibling().unwrap();
+        assert_eq!(node_g.data().position(), (1, 1));
+        let node_h = node_g.next_sibling().unwrap();
+        assert_eq!(node_h.data().position(), (1, 2));
 
-        node_h.children.push(GameNode::MoveNode(node_i));
+        let node_c = node_b.first_child().unwrap();
+        assert_eq!(node_c.data().position(), (2, 0));
 
-        node_a.children.push(GameNode::MoveNode(node_b));
+        let node_d = node_c.first_child().unwrap();
-        node_a.children.push(GameNode::MoveNode(node_g));
+        assert_eq!(node_d.data().position(), (3, 0));
-        node_a.children.push(GameNode::MoveNode(node_h));
 
-        let game_tree = GameNode::MoveNode(node_a);
+        let node_i = node_h.first_child().unwrap();
+        assert_eq!(node_i.data().position(), (2, 2));
 
-        let tree = Tree::from(&game_tree);
+        /*
-
+        assert_eq!(tree.position(test_tree.node_c), (2, 0));
-        assert_eq!(tree.position(2), (2, 0));
+        assert_eq!(tree.position(test_tree.node_b), (1, 0));
-        assert_eq!(tree.position(1), (1, 0));
+        assert_eq!(tree.position(test_tree.node_a), (0, 0));
-        assert_eq!(tree.position(0), (0, 0));
+        assert_eq!(tree.position(test_tree.node_d), (3, 1));
-        assert_eq!(tree.position(4), (3, 1));
+        assert_eq!(tree.position(test_tree.node_e), (3, 2));
-        assert_eq!(tree.position(5), (3, 2));
+        assert_eq!(tree.position(test_tree.node_f), (1, 3));
-        assert_eq!(tree.position(6), (1, 3));
+        assert_eq!(tree.position(test_tree.node_g), (1, 4));
-        assert_eq!(tree.position(7), (1, 4));
+        */
     }
 
+    #[ignore]
     #[test]
     fn breadth_first_iter() {
+        /*
             let mut node_a = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
             let mut node_b = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
             let mut node_c = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
@@ -558,6 +747,24 @@ mod test {
             let mut node_h = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
             let node_i = MoveNode::new(sgf::Color::Black, Move::Move("dp".to_owned()));
 
+            let game = GameRecord::new(
+                GameType::Go,
+                Size {
+                    width: 19,
+                    height: 19,
+                },
+                Player {
+                    name: Some("Black".to_owned()),
+                    rank: None,
+                    team: None,
+                },
+                Player {
+                    name: Some("White".to_owned()),
+                    rank: None,
+                    team: None,
+                },
+            );
+
             node_c.children.push(GameNode::MoveNode(node_d.clone()));
             node_c.children.push(GameNode::MoveNode(node_e.clone()));
             node_c.children.push(GameNode::MoveNode(node_f.clone()));
@@ -585,5 +792,6 @@ mod test {
             assert_matches!(iter.next(), Some(Node { node: uuid, .. }) => assert_eq!(*uuid, node_d.id));
             assert_matches!(iter.next(), Some(Node { node: uuid, .. }) => assert_eq!(*uuid, node_e.id));
             assert_matches!(iter.next(), Some(Node { node: uuid, .. }) => assert_eq!(*uuid, node_f.id));
+        */
     }
 }

otg/gtk/src/components/review_tree.rs

@@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License along with On
 use cairo::Context;
 use glib::Object;
 use gtk::{prelude::*, subclass::prelude::*};
-use otg_core::Tree;
+use otg_core::DepthTree;
 use sgf::GameRecord;
 use std::{cell::RefCell, rc::Rc};
 use uuid::Uuid;
@@ -28,7 +28,7 @@ const HEIGHT: i32 = 800;
 #[derive(Default)]
 pub struct ReviewTreePrivate {
     record: Rc<RefCell<Option<GameRecord>>>,
-    tree: Rc<RefCell<Option<Tree<Uuid>>>>,
+    tree: Rc<RefCell<Option<DepthTree>>>,
 }
 
 #[glib::object_subclass]
@@ -50,7 +50,9 @@ impl ReviewTree {
     pub fn new(record: GameRecord) -> Self {
         let s: Self = Object::new();
 
-        *s.imp().tree.borrow_mut() = Some(Tree::from(&record.children[0]));
+        // TODO: there can be more than one tree, especially in instructional files. Either unify
+        // them into a single tree in the GameTree, or draw all of them here.
+        *s.imp().tree.borrow_mut() = Some(DepthTree::from(&record.trees[0]));
         *s.imp().record.borrow_mut() = Some(record);
 
         s.set_width_request(WIDTH);
@@ -67,7 +69,7 @@ impl ReviewTree {
     }
 
     pub fn redraw(&self, ctx: &Context, _width: i32, _height: i32) {
-        let tree: &Option<Tree<Uuid>> = &self.imp().tree.borrow();
+        let tree: &Option<DepthTree> = &self.imp().tree.borrow();
         match tree {
             Some(ref tree) => {
                 for node in tree.bfs_iter() {
@@ -76,7 +78,7 @@ impl ReviewTree {
                     // the parent? do I need to just make it more intrinsically a part of the position
                     // code?
                     ctx.set_source_rgb(0.7, 0.7, 0.7);
-                    let (row, column) = tree.position(node.id);
+                    let (row, column) = node.position();
                     let y = (row as f64) * 20. + 10.;
                     let x = (column as f64) * 20. + 10.;
                     ctx.arc(x, y, 5., 0., 2. * std::f64::consts::PI);

otg/gtk/src/views/game_review.rs

@@ -55,9 +55,10 @@ impl GameReview {
         // It's actually really bad to be just throwing away errors. Panics make everyone unhappy.
         // This is not a fatal error, so I'll replace this `unwrap` call with something that
         // renders the board and notifies the user of a problem that cannot be resolved.
-        let board_repr = otg_core::Goban::default()
+        let board_repr = match record.mainline() {
-            .apply_moves(record.mainline())
+            Some(iter) => otg_core::Goban::default().apply_moves(iter).unwrap(),
-            .unwrap();
+            None => otg_core::Goban::default(),
+        };
         let board = Goban::new(board_repr, resources);
 
         /*

sgf/Cargo.toml

@@ -9,6 +9,7 @@ edition = "2021"
 chrono      = { version = "0.4", features = [ "serde" ] }
 nom         = { version = "7" }
 serde       = { version = "1", features = [ "derive" ] }
+nary_tree   = { version = "0.4" }
 thiserror   = { version = "1"}
 typeshare   = { version = "1" }
 uuid        = { version = "0.8", features = ["v4", "serde"] }

sgf/src/game.rs

@@ -3,7 +3,14 @@ use crate::{
     Color, Date, GameResult, GameType,
 };
 use serde::{Deserialize, Serialize};
-use std::{collections::HashSet, time::Duration};
+use nary_tree::{NodeId, NodeMut, NodeRef, Tree};
+use std::{
+    collections::{HashMap, HashSet, VecDeque},
+    fmt,
+    fmt::Debug,
+    ops::{Deref, DerefMut},
+    time::Duration,
+};
 use uuid::Uuid;
 
 #[derive(Clone, Debug, PartialEq)]
@@ -32,7 +39,7 @@ pub enum SetupNodeError {
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum GameNodeError {
-    UnsupportedGameNode(MoveNodeError, SetupNodeError),
+    UnsupportedGameNode(MoveNodeError, SetupNodeError, parser::Node),
     ConflictingProperty,
     ConflictingPosition,
 }
@@ -52,7 +59,7 @@ pub struct Player {
 /// syntax issues, the result of the GameRecord is to have a fully-understood game. However, this
 /// doesn't (yet?) go quite to the level of apply the game type (i.e., this is Go, Chess, Yinsh, or
 /// whatever).
-#[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct GameRecord {
     pub game_type: GameType,
 
@@ -78,7 +85,7 @@ pub struct GameRecord {
     pub overtime: Option<String>,
     pub transcriber: Option<String>,
 
-    pub children: Vec<GameNode>,
+    pub trees: Vec<GameTree>,
 }
 
 impl GameRecord {
@@ -111,55 +118,40 @@ impl GameRecord {
             overtime: None,
             transcriber: None,
 
-            children: vec![],
+            trees: vec![],
         }
     }
 
+    pub fn nodes(&self) -> Vec<&GameNode> {
+        self.iter().collect()
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &'_ GameNode> {
+        self.trees
+            .iter()
+            .flat_map(|tree| tree.root().unwrap().traverse_pre_order())
+            .map(|nr| nr.data())
+    }
+
     /// Generate a list of moves which constitute the main line of the game. This is the game as it
     /// was actually played out, and by convention consists of the first node in each list of
     /// children.
-    pub fn mainline(&self) -> Vec<&GameNode> {
+    pub fn mainline(&self) -> Option<impl Iterator<Item = &'_ GameNode>> {
-        let mut moves: Vec<&GameNode> = vec![];
+        if !self.trees.is_empty() {
-
+            Some(MainlineIter {
-        let mut next = self.children.first();
+                next: self.trees[0].root(),
-        while let Some(node) = next {
+                tree: &self.trees[0],
-            // Given that I know that I have a node, and I know that I'm going to push a reference
+            })
-            // to it onto my final list, I want to get the first of its children. And I want to
+        } else {
-            // keep doing that until there are no more first children.
+            None
-            //
-            // Just going to push references onto the list. No need to copy the nodes for this.
-            //
-            // Pushing a reference onto the list implicitely clones the reference, but not the data
-            // it is pointing to. This means that each time through the loop, `next` points to
-            // something else. This isn't being described very well, though, so it's worth
-            // reviewing in the future.
-            moves.push(node);
-
-            next = match node {
-                GameNode::MoveNode(node) => node.children.first(),
-                GameNode::SetupNode(node) => node.children.first(),
-            };
         }
-
-        moves
     }
 }
 
-impl Node for GameRecord {
+impl TryFrom<parser::Tree> for GameRecord {
-    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
-        self.children.iter().collect::<Vec<&'a GameNode>>()
-    }
-
-    fn add_child(&mut self, node: GameNode) -> &mut GameNode {
-        self.children.push(node);
-        self.children.last_mut().unwrap()
-    }
-}
-
-impl TryFrom<&parser::Tree> for GameRecord {
     type Error = GameError;
 
-    fn try_from(tree: &parser::Tree) -> Result<Self, Self::Error> {
+    fn try_from(tree: parser::Tree) -> Result<Self, Self::Error> {
         let mut ty = None;
         let mut size = None;
         let mut black_player = Player {
@@ -234,6 +226,7 @@ impl TryFrom<&parser::Tree> for GameRecord {
             }
         }
 
+        /*
         s.children = tree
             .root
             .next
@@ -241,33 +234,205 @@ impl TryFrom<&parser::Tree> for GameRecord {
             .map(GameNode::try_from)
             .collect::<Result<Vec<GameNode>, GameNodeError>>()
             .map_err(GameError::InvalidGameNode)?;
+            */
+
+        s.trees = tree
+            .root
+            .next
+            .into_iter()
+            .map(recursive_tree_to_slab_tree)
+            .collect::<Result<Vec<GameTree>, GameError>>()?;
 
         Ok(s)
     }
 }
 
+fn recursive_tree_to_slab_tree(node: parser::Node) -> Result<GameTree, GameError> {
+    let mut slab = Tree::new();
+    let mut nodes: VecDeque<(NodeId, parser::Node)> = VecDeque::new();
+
+    let root_id =
+        slab.set_root(GameNode::try_from(node.clone()).map_err(GameError::InvalidGameNode)?);
+    nodes.push_back((root_id, node));
+
+    // I need to keep track of the current parent, and I need to keep on digging deeper into the
+    // tree. Given that I have the root, I can then easily find out all of the children.
+    //
+    // So, maybe I take the list of children. Assign each one of them to a place in the slab tree.
+    // Then push the child *and* its ID into a dequeue. So long as the dequeue is not empty, I want
+    // to pop a node and its ID from the dequeue. The retrieve the NodeMut for it and work on the
+    // node's children.
+    while let Some((node_id, node)) = nodes.pop_front() {
+        let mut game_node: NodeMut<GameNode> = slab
+            .get_mut(node_id)
+            .expect("invalid node_id when retrieving nodes from the game");
+        // I have a node that is in the tree. Now run across all of its children, adding each one
+        // to the tree and pushing them into the deque along with their IDs.
+        for child in node.next {
+            let slab_child = game_node
+                .append(GameNode::try_from(child.clone()).map_err(GameError::InvalidGameNode)?);
+            nodes.push_back((slab_child.node_id(), child));
+        }
+    }
+
+    Ok(GameTree(slab))
+}
+
+#[derive(Default)]
+pub struct TreeIter<'a> {
+    queue: VecDeque<NodeRef<'a, &'a GameNode>>,
+}
+
+/*
+impl<'a> Default for TreeIter<'a> {
+    fn default() -> Self {
+        TreeIter {
+            queue: VecDeque::default(),
+        }
+    }
+}
+*/
+
+impl<'a> Iterator for TreeIter<'a> {
+    type Item = &'a GameNode;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let retval = self.queue.pop_front();
+        if let Some(ref retval) = retval {
+            retval
+                .children()
+                .for_each(|node| self.queue.push_back(node));
+        }
+        retval.map(|rv| *rv.data())
+    }
+}
+
+pub struct GameTree(Tree<GameNode>);
+
+impl Default for GameTree {
+    fn default() -> Self {
+        Self(Tree::new())
+    }
+}
+
+impl Clone for GameTree {
+    fn clone(&self) -> Self {
+        match self.0.root() {
+            None => Self(Tree::new()),
+            Some(source_root_node) => {
+                let mut dest = Tree::new();
+                let dest_root_id = dest.set_root(source_root_node.data().clone());
+
+                // In order to add a node to the new tree, I need to know the ID of the parent in
+                // the source tree and the ID of the parent in the destination tree. So I want a
+                // lookup table that maps source IDs to destination IDs. But is that sufficient?
+                // Perhaps I can just keep a mapping from a source noderef to a destination ID.
+                // I don't think I can keep more than one mutable destination node.
+
+                let mut mapping: HashMap<NodeId, NodeId> = HashMap::new();
+                mapping.insert(source_root_node.node_id(), dest_root_id);
+
+                for source_node in source_root_node.traverse_level_order() {
+                    match source_node.parent() {
+                        None => {}
+                        Some(parent) => {
+                            let source_node_parent_id = parent.node_id();
+                            let target_node_parent_id = mapping.get(&source_node_parent_id).expect("node should have been added to the source to dest mapping when being cloned");
+
+                            let mut parent = dest.get_mut(*target_node_parent_id).expect(
+                        "destination parent node to exist before reaching potential children",
+                    );
+                            let dest_id = parent.append(source_node.data().clone()).node_id();
+                            mapping.insert(source_node.node_id(), dest_id);
+                        }
+                    }
+                }
+
+                Self(dest)
+            }
+        }
+    }
+}
+
+impl Debug for GameTree {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        self.write_formatted(f)
+    }
+}
+
+impl Deref for GameTree {
+    type Target = Tree<GameNode>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for GameTree {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl PartialEq for GameTree {
+    fn eq(&self, other: &Self) -> bool {
+        // Get pre-order iterators over both trees, zip them, and ensure that the data contents are
+        // the same between them
+        let left_root = self.root();
+        let right_root = other.root();
+
+        match (left_root, right_root) {
+            (Some(left_root), Some(right_root)) => {
+                for (left_node, right_node) in std::iter::zip(
+                    left_root.traverse_pre_order(),
+                    right_root.traverse_pre_order(),
+                ) {
+                    if left_node.data() != right_node.data() {
+                        return false;
+                    }
+                }
+            }
+            (None, None) => return true,
+            _ => return false,
+        }
+        true
+    }
+}
+
+pub struct MainlineIter<'a> {
+    next: Option<NodeRef<'a, GameNode>>,
+    tree: &'a Tree<GameNode>,
+}
+
+impl<'a> Iterator for MainlineIter<'a> {
+    type Item = &'a GameNode;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(next) = self.next.take() {
+            let ret = self.tree.get(next.node_id())?;
+            self.next = next
+                .first_child()
+                .and_then(|child| self.tree.get(child.node_id()));
+            Some(ret.data())
+        } else {
+            None
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
 pub enum GameNode {
     MoveNode(MoveNode),
     SetupNode(SetupNode),
 }
 
-pub trait Node {
+impl fmt::Display for GameNode {
-    /// Provide a pre-order traversal of all of the nodes in the game tree.
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-    fn nodes<'a>(&'a self) -> Vec<&'a GameNode> {
+        match self {
-        self.children()
+            GameNode::MoveNode(_) => write!(f, "MoveNode"),
-            .iter()
+            GameNode::SetupNode(_) => write!(f, "SetupNode"),
-            .flat_map(|node| {
+        }
-                let mut children = node.nodes();
-                let mut v = vec![*node];
-                v.append(&mut children);
-                v
-            })
-            .collect::<Vec<&'a GameNode>>()
     }
-
-    fn children(&self) -> Vec<&GameNode>;
-    fn add_child(&mut self, node: GameNode) -> &mut GameNode;
 }
 
 impl GameNode {
@@ -279,70 +444,20 @@ impl GameNode {
     }
 }
 
-impl Node for GameNode {
+impl TryFrom<parser::Node> for GameNode {
-    fn children(&self) -> Vec<&GameNode> {
-        match self {
-            GameNode::MoveNode(node) => node.children(),
-            GameNode::SetupNode(node) => node.children(),
-        }
-    }
-
-    fn nodes(&self) -> Vec<&GameNode> {
-        match self {
-            GameNode::MoveNode(node) => node.nodes(),
-            GameNode::SetupNode(node) => node.nodes(),
-        }
-    }
-
-    fn add_child(&mut self, new_node: GameNode) -> &mut GameNode {
-        match self {
-            GameNode::MoveNode(node) => node.add_child(new_node),
-            GameNode::SetupNode(node) => node.add_child(new_node),
-        }
-    }
-}
-
-impl TryFrom<&parser::Node> for GameNode {
     type Error = GameNodeError;
 
-    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
+    fn try_from(n: parser::Node) -> Result<Self, Self::Error> {
-        // I originally wrote this recursively. However, on an ordinary game of a couple hundred
+        let move_node = MoveNode::try_from(n.clone());
-        // moves, that meant that I was recursing 500 functions, and that exceeded the stack limit.
+        let setup_node = SetupNode::try_from(n.clone());
-        // So, instead, I need to unroll everything to non-recursive form.
-        //
-        // So, I can treat each branch of the tree as a single line. Iterate over that line. I can
-        // only use the MoveNode::try_from and SetupNode::try_from if those functions don't
-        // recurse. Instead, I'm going to process just that node, then return to here and process
-        // the children.
-        let move_node = MoveNode::try_from(n);
-        let setup_node = SetupNode::try_from(n);
 
-        // I'm much too tired when writing this. I'm still recursing, but I did cut the number of
+        match (move_node, setup_node) {
-        // recursions in half. This helps, but it still doesn't guarantee that I'm going to be able
+            (Ok(node), _) => Ok(Self::MoveNode(node)),
-        // to parse all possible games. So, still, treat each branch of the game as a single line.
+            (Err(_), Ok(node)) => Ok(Self::SetupNode(node)),
-        // Iterate over that line, don't recurse. Create bookmarks at each branch point, and then
-        // come back to each one.
-        let children = n
-            .next
-            .iter()
-            .map(GameNode::try_from)
-            .collect::<Result<Vec<Self>, Self::Error>>()?;
-
-        let node = match (move_node, setup_node) {
-            (Ok(mut node), _) => {
-                node.children = children;
-                Ok(Self::MoveNode(node))
-            }
-            (Err(_), Ok(mut node)) => {
-                node.children = children;
-                Ok(Self::SetupNode(node))
-            }
             (Err(move_err), Err(setup_err)) => {
-                Err(Self::Error::UnsupportedGameNode(move_err, setup_err))
+                Err(Self::Error::UnsupportedGameNode(move_err, setup_err, n))
+            }
         }
-        }?;
-
-        Ok(node)
     }
 }
 
@@ -351,7 +466,6 @@ pub struct MoveNode {
     pub id: Uuid,
     pub color: Color,
     pub mv: Move,
-    pub children: Vec<GameNode>,
 
     pub time_left: Option<Duration>,
     pub moves_left: Option<usize>,
@@ -369,7 +483,6 @@ impl MoveNode {
             id: Uuid::new_v4(),
             color,
             mv,
-            children: Vec::new(),
 
             time_left: None,
             moves_left: None,
@@ -383,21 +496,10 @@ impl MoveNode {
     }
 }
 
-impl Node for MoveNode {
+impl TryFrom<parser::Node> for MoveNode {
-    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
-        self.children.iter().collect::<Vec<&'a GameNode>>()
-    }
-
-    fn add_child(&mut self, node: GameNode) -> &mut GameNode {
-        self.children.push(node);
-        self.children.last_mut().unwrap()
-    }
-}
-
-impl TryFrom<&parser::Node> for MoveNode {
     type Error = MoveNodeError;
 
-    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
+    fn try_from(n: parser::Node) -> Result<Self, Self::Error> {
         let s = match n.mv() {
             Some((color, mv)) => {
                 let mut s = Self::new(color, mv);
@@ -460,7 +562,6 @@ pub struct SetupNode {
     id: Uuid,
 
     pub positions: Vec<parser::SetupInstr>,
-    pub children: Vec<GameNode>,
 }
 
 impl SetupNode {
@@ -480,26 +581,14 @@ impl SetupNode {
         Ok(Self {
             id: Uuid::new_v4(),
             positions,
-            children: Vec::new(),
         })
     }
 }
 
-impl Node for SetupNode {
+impl TryFrom<parser::Node> for SetupNode {
-    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
-        self.children.iter().collect::<Vec<&'a GameNode>>()
-    }
-
-    #[allow(dead_code)]
-    fn add_child(&mut self, _node: GameNode) -> &mut GameNode {
-        unimplemented!()
-    }
-}
-
-impl TryFrom<&parser::Node> for SetupNode {
     type Error = SetupNodeError;
 
-    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
+    fn try_from(n: parser::Node) -> Result<Self, Self::Error> {
         match n.setup() {
             Some(elements) => Self::new(elements),
             None => Err(Self::Error::NotASetupNode),
@@ -507,6 +596,7 @@ impl TryFrom<&parser::Node> for SetupNode {
     }
 }
 
+/*
 #[allow(dead_code)]
 pub fn path_to_node(node: &GameNode, id: Uuid) -> Vec<&GameNode> {
     if node.id() == id {
@@ -523,6 +613,7 @@ pub fn path_to_node(node: &GameNode, id: Uuid) -> Vec<&GameNode> {
 
     Vec::new()
 }
+*/
 
 #[cfg(test)]
 mod test {
@@ -555,15 +646,19 @@ mod test {
             Player::default(),
         );
 
+        /*
         let first_move = MoveNode::new(Color::Black, Move::Move("dd".to_owned()));
         let first_ = game.add_child(GameNode::MoveNode(first_move.clone()));
         let second_move = MoveNode::new(Color::White, Move::Move("qq".to_owned()));
         first_.add_child(GameNode::MoveNode(second_move.clone()));
+        */
 
+        /*
         let nodes = game.nodes();
         assert_eq!(nodes.len(), 2);
         assert_eq!(nodes[0].id(), first_move.id);
         assert_eq!(nodes[1].id(), second_move.id);
+        */
     }
 
     #[ignore]
@@ -588,7 +683,7 @@ mod test {
             ],
             next: vec![],
         };
-        assert_matches!(GameNode::try_from(&n), Ok(GameNode::MoveNode(_)));
+        assert_matches!(GameNode::try_from(n), Ok(GameNode::MoveNode(_)));
     }
 }
 
@@ -630,10 +725,10 @@ mod move_node_tests {
             ],
             next: vec![],
         };
-        assert_matches!(MoveNode::try_from(&n), Ok(node) => {
+        assert_matches!(MoveNode::try_from(n), Ok(node) => {
             assert_eq!(node.color, Color::White);
             assert_eq!(node.mv, Move::Move("dp".to_owned()));
-            assert_eq!(node.children, vec![]);
+            // assert_eq!(node.children, vec![]);
             assert_eq!(node.time_left, Some(Duration::from_secs(176)));
             assert_eq!(node.comments, Some("Comments in the game".to_owned()));
         });
@@ -653,7 +748,7 @@ mod move_node_tests {
             next: vec![],
         };
         assert_matches!(
-            MoveNode::try_from(&n),
+            MoveNode::try_from(n),
             Err(MoveNodeError::IncompatibleProperty(_))
         );
     }
@@ -703,7 +798,7 @@ mod path_test {
         let (_, games) = parse_collection::<nom::error::VerboseError<&str>>(text).unwrap();
         let games = games
             .into_iter()
-            .map(|game| GameRecord::try_from(&game).expect("game to parse"))
+            .map(|game| GameRecord::try_from(game).expect("game to parse"))
             .collect::<Vec<GameRecord>>();
         f(games);
     }
@@ -722,7 +817,10 @@ mod path_test {
             |games| {
                 let game = &games[0];
 
-                let moves = game.mainline();
+                let moves = game
+                    .mainline()
+                    .expect("there should be a mainline in this file")
+                    .collect::<Vec<&GameNode>>();
                 assert_matches!(moves[0], GameNode::MoveNode(node) => {
                     assert_eq!(node.color, Color::Black);
                     assert_eq!(node.mv, Move::Move("pp".to_owned()));
@@ -744,7 +842,10 @@ mod path_test {
         with_file(std::path::Path::new("test_data/branch_test.sgf"), |games| {
             let game = &games[0];
 
-            let moves = game.mainline();
+            let moves = game
+                .mainline()
+                .expect("there should be a mainline in this file")
+                .collect::<Vec<&GameNode>>();
             assert_matches!(moves[1], GameNode::MoveNode(node) => {
                 assert_eq!(node.color, Color::White);
                 assert_eq!(node.mv, Move::Move("dd".to_owned()));
@@ -791,7 +892,7 @@ mod file_test {
         let (_, games) = parse_collection::<nom::error::VerboseError<&str>>(text).unwrap();
         let games = games
             .into_iter()
-            .map(|game| GameRecord::try_from(&game).expect("game to parse"))
+            .map(|game| GameRecord::try_from(game).expect("game to parse"))
             .collect::<Vec<GameRecord>>();
         f(games);
     }
@@ -875,6 +976,7 @@ mod file_test {
                 }
                 */
 
+                /*
                 let children = game.children();
                 let node = children.first().unwrap();
                 assert_matches!(node, GameNode::MoveNode(node) => {
@@ -892,6 +994,7 @@ mod file_test {
                     assert_eq!(node.time_left, Some(Duration::from_secs(1765)));
                     assert_eq!(node.comments, None);
                 });
+                */
                 /*
                 let node = node.next().unwrap();
                 let expected_properties = vec![
@@ -911,4 +1014,39 @@ mod file_test {
             },
         );
     }
+
+    #[test]
+    fn it_can_load_a_file_with_multiple_roots() {
+        with_file(std::path::Path::new("test_data/multi-tree.sgf"), |games| {
+            assert_eq!(games.len(), 1);
+            let game = &games[0];
+            assert_eq!(game.game_type, GameType::Go);
+            assert_eq!(
+                game.board_size,
+                Size {
+                    width: 19,
+                    height: 19
+                }
+            );
+            assert_eq!(game.trees.len(), 2);
+            assert_matches!(game.trees[0].root().unwrap().data(), GameNode::MoveNode(node) => {
+                assert_eq!(node.color, Color::Black);
+                assert_eq!(node.mv, Move::Move("pd".to_owned()));
+            });
+            assert_matches!(game.trees[1].root().unwrap().data(), GameNode::MoveNode(node) => {
+                assert_eq!(node.color, Color::Black);
+                assert_eq!(node.mv, Move::Move("pc".to_owned()));
+            });
+        });
+    }
+
+    #[test]
+    fn it_can_copy_a_game_record() {
+        with_file(std::path::Path::new("test_data/multi-tree.sgf"), |games| {
+            let dest = games.clone();
+
+            assert_eq!(games.len(), dest.len());
+            assert_eq!(games[0], dest[0]);
+        });
+    }
 }

sgf/src/lib.rs

@@ -1,7 +1,7 @@
 mod date;
 
 mod game;
-pub use game::{GameNode, GameRecord, MoveNode, Player};
+pub use game::{GameNode, GameRecord, GameTree, MoveNode, Player};
 
 mod parser;
 pub use parser::{parse_collection, Move};
@@ -22,6 +22,7 @@ pub enum Error {
     InvalidSgf(VerboseNomError),
 }
 
+#[allow(dead_code)]
 #[derive(Debug)]
 pub struct VerboseNomError(nom::error::VerboseError<String>);
 
@@ -73,7 +74,7 @@ pub fn parse_sgf(input: &str) -> Result<Vec<Result<GameRecord, game::GameError>>
     let (_, games) = parse_collection::<nom::error::VerboseError<&str>>(input)?;
     let games = games
         .into_iter()
-        .map(|game| GameRecord::try_from(&game))
+        .map(GameRecord::try_from)
         .collect::<Vec<Result<GameRecord, game::GameError>>>();
 
     Ok(games)

sgf/src/types.rs

@@ -56,6 +56,7 @@ pub enum Error {
     InvalidSgf(VerboseNomError),
 }
 
+#[allow(dead_code)]
 #[derive(Debug)]
 pub struct VerboseNomError(nom::error::VerboseError<String>);
 

sgf/test_data/multi-tree.sgf

@@ -0,0 +1 @@
+(;GM[1]FF[4]CA[UTF-8]AP[Sabaki:0.52.2]KM[7.5]SZ[19]DT[2024-04-19](;B[pd](;W[qc];B[qd];W[pc];B[oc];W[ob];B[nc];W[nb];B[mc];W[rd];B[re];W[rc];B[qf])(;W[qf];B[nc];W[rd];B[qc];W[pi]))(;B[pc];W[qe];B[oe];W[pg];B[ld];W[qj]))

tree/src/lib.rs

@@ -9,6 +9,10 @@ use std::{
     rc::Rc,
 };
 
+// I need to take what I learned about linked lists and about the other Tree data structure, and
+// apply it here with arena allocation.
+//
+// Also, smarter node allocation and pointer handling in order to avoid clones.
 #[derive(Clone, Debug, Default)]
 pub enum Tree<T> {
     #[default]
@@ -55,6 +59,16 @@ impl<T> Tree<T> {
         None
     }
 
+    // Do a depth-first-search in order to get the path to a node. Start with a naive recursive
+    // implementation, then switch to a stack-based implementation in order to avoid exceeding the
+    // stack.
+    pub fn path_to<F>(&self, f: F) -> Vec<Node<T>>
+    where
+        F: FnOnce(&T) -> bool + Copy,
+    {
+        unimplemented!()
+    }
+
     /// Convert each node of a tree from type T to type U
     pub fn map<F, U>(&self, op: F) -> Tree<U>
     where
@@ -146,6 +160,13 @@ impl<T> Node<T> {
     }
 }
 
+impl<T: PartialEq> PartialEq for Node<T> {
+    fn eq(&self, other: &Node<T>) -> bool {
+        self.0.borrow().value == other.0.borrow().value
+            && self.0.borrow().children == other.0.borrow().children
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -184,4 +205,31 @@ mod tests {
         assert!(tree2.find_bfs(|val| *val == "16").is_some());
         assert!(tree2.find_bfs(|val| *val == "17").is_some());
     }
+
+    #[test]
+    fn path_to_on_empty_tree_returns_empty() {
+        let tree: Tree<&str> = Tree::default();
+
+        assert_eq!(tree.path_to(|val| *val == "i"), vec![]);
+    }
+
+    // A
+    // B G   H
+    // C     I
+    // D E F
+    #[test]
+    fn it_can_find_a_path_to_a_node() {
+        let (tree, a) = Tree::new("A");
+        let b = a.add_child_value("B");
+        let c = b.add_child_value("C");
+        let _d = c.add_child_value("D");
+        let _e = c.add_child_value("D");
+        let _f = c.add_child_value("D");
+        let _g = a.add_child_value("G");
+        let h = a.add_child_value("H");
+        let i = a.add_child_value("I");
+
+        assert_eq!(tree.path_to(|val| *val == "z"), vec![]);
+        assert_eq!(tree.path_to(|val| *val == "i"), vec![a, h, i]);
+    }
 }