feat(drawing/drawing): Make it possible to have multiple outers for each gear

src/drawing/collect.rs

@@ -2,12 +2,12 @@
 //
 // SPDX-License-Identifier: MIT
 
-use crate::graph::MakeRef;
+use petgraph::visit::Walker;
 
 use super::{
     band::{BandTermsegIndex, BandUid},
     bend::LooseBendIndex,
-    gear::{GearIndex, GetNextGear},
+    gear::WalkOutwards,
     graph::PrimitiveIndex,
     loose::{GetPrevNextLoose, LooseIndex},
     primitive::GetJoints,
@@ -26,9 +26,7 @@ pub trait Collect {
 
     fn bend_bow(&self, bend: LooseBendIndex) -> Vec<PrimitiveIndex>;
 
-    fn bend_outer_bows(&self, bend: LooseBendIndex) -> Vec<PrimitiveIndex>;
+    fn bend_outward_bows(&self, bend: LooseBendIndex) -> Vec<PrimitiveIndex>;
-
-    fn wraparounded_bows(&self, around: GearIndex) -> Vec<PrimitiveIndex>;
 }
 
 impl<CW: Clone, Cel: Copy, R: AccessRules> Collect for Drawing<CW, Cel, R> {
@@ -62,35 +60,12 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Collect for Drawing<CW, Cel, R> {
         v
     }
 
-    fn bend_outer_bows(&self, bend: LooseBendIndex) -> Vec<PrimitiveIndex> {
+    fn bend_outward_bows(&self, bend: LooseBendIndex) -> Vec<PrimitiveIndex> {
         let mut v = vec![];
-        let mut gear = bend;
 
-        while let Some(outer) = self.primitive(gear).outer() {
+        let mut outwards = self.primitive(bend).outwards();
-            v.append(&mut self.bend_bow(outer));
+        while let Some(next) = outwards.walk_next(self) {
-            gear = outer;
+            v.append(&mut self.bend_bow(next));
-        }
-
-        v
-    }
-
-    fn wraparounded_bows(&self, around: GearIndex) -> Vec<PrimitiveIndex> {
-        let mut v = vec![];
-        let mut gear = around;
-
-        while let Some(bend) = gear.ref_(self).next_gear() {
-            let primitive = self.primitive(bend);
-
-            v.push(bend.into());
-
-            let joints = primitive.joints();
-            v.push(joints.0.into());
-            v.push(joints.1.into());
-
-            v.push(self.primitive(joints.0).seg().unwrap().into());
-            v.push(self.primitive(joints.1).seg().unwrap().into());
-
-            gear = bend.into();
         }
 
         v

src/drawing/drawing.rs

@@ -5,6 +5,7 @@
 use contracts_try::{debug_ensures, debug_invariant};
 use derive_getters::Getters;
 use geo::{Point, Polygon};
+use petgraph::visit::Walker;
 
 use core::fmt;
 use rstar::{RTree, AABB};
@@ -17,7 +18,7 @@ use crate::{
         cane::Cane,
         collect::Collect,
         dot::{DotIndex, DotWeight, FixedDotIndex, FixedDotWeight, LooseDotIndex, LooseDotWeight},
-        gear::{GearIndex, GetNextGear},
+        gear::GearIndex,
         graph::{GetMaybeNet, IsInLayer, MakePrimitive, PrimitiveIndex, PrimitiveWeight},
         guide::Guide,
         loose::{GetPrevNextLoose, Loose, LooseIndex},
@@ -44,6 +45,8 @@ use crate::{
     math::RotationSense,
 };
 
+use super::gear::{GetOuterGears, WalkOutwards};
+
 #[derive(Clone, Copy, Error)]
 pub enum DrawingException {
     #[error(transparent)]
@@ -255,7 +258,7 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
                 LooseIndex::Bend(bend) => {
                     bends.push(bend);
 
-                    if let Some(outer) = self.primitive(bend).outer() {
+                    for outer in self.primitive(bend).outers().collect::<Vec<_>>() {
                         outers.push(outer);
                         self.reattach_bend(recorder, outer, self.primitive(bend).inner());
                     }
@@ -509,10 +512,11 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
                 }
             }
             //
-            if let Some(next_gear) = around.ref_(self).next_gear() {
+            let mut outwards = around.ref_(self).outwards();
-                if let Some(next_gear_net) = next_gear.primitive(self).maybe_net() {
+            while let Some(gear) = outwards.walk_next(self) {
+                if let Some(next_gear_net) = gear.primitive(self).maybe_net() {
                     if net == next_gear_net {
-                        return Err(AlreadyConnected(net, next_gear.into()).into());
+                        return Err(AlreadyConnected(net, gear.into()).into());
                     }
                 }
             }
@@ -666,7 +670,7 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
         bend_weight: LooseBendWeight,
         sense: RotationSense,
     ) -> Result<Cane, DrawingException> {
-        let maybe_next_gear = around.ref_(self).next_gear();
+        let outer_gears = around.ref_(self).outer_gears();
         let cane = self.add_cane_with_infringement_filtering(
             recorder,
             from,
@@ -678,11 +682,11 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
             &|_drawing, _infringer, _infringee| true,
         )?;
 
-        if let Some(next_gear) = maybe_next_gear {
+        for gear in outer_gears {
-            self.reattach_bend(recorder, next_gear, Some(cane.bend));
+            self.reattach_bend(recorder, gear, Some(cane.bend));
         }
 
-        if let Some(outer) = self.primitive(cane.bend).outer() {
+        for outer in self.primitive(cane.bend).outers().collect::<Vec<_>>() {
             self.update_this_and_outward_bows(recorder, outer)
                 .inspect_err(|_| {
                     let joint = self.primitive(cane.bend).other_joint(cane.dot);
@@ -700,81 +704,88 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
         recorder: &mut DrawingEdit<CW, Cel>,
         around: LooseBendIndex,
     ) -> Result<(), DrawingException> {
-        let mut maybe_rail = Some(around);
+        self.update_bow(recorder, around)?;
 
-        while let Some(rail) = maybe_rail {
+        let mut outwards = self.primitive(around).outwards();
-            let rail_primitive = self.primitive(rail);
+        while let Some(rail) = outwards.walk_next(self) {
-            let joints = rail_primitive.joints();
+            self.update_bow(recorder, rail)?;
-            let width = rail_primitive.width();
-
-            let from_head = self.rear_head(joints.1);
-            let to_head = self.rear_head(joints.0);
-
-            let (from, to, offset) = if let Some(inner) = rail_primitive.inner() {
-                let inner = inner.into();
-                let from = self.guide_for_head_around_bend_segment(
-                    &from_head,
-                    inner,
-                    RotationSense::Counterclockwise,
-                    width,
-                )?;
-                let to = self.guide_for_head_around_bend_segment(
-                    &to_head,
-                    inner,
-                    RotationSense::Clockwise,
-                    width,
-                )?;
-                let offset = self.guide_for_head_around_bend_offset(&from_head, inner, width);
-                (from, to, offset)
-            } else {
-                let core = rail_primitive.core().into();
-                let from = self.guide_for_head_around_dot_segment(
-                    &from_head,
-                    core,
-                    RotationSense::Counterclockwise,
-                    width,
-                )?;
-                let to = self.guide_for_head_around_dot_segment(
-                    &to_head,
-                    core,
-                    RotationSense::Clockwise,
-                    width,
-                )?;
-                let offset = self.guide_for_head_around_dot_offset(&from_head, core, width);
-                (from, to, offset)
-            };
-
-            let rail_outer_bows = self.bend_outer_bows(rail);
-
-            // Commenting out these two makes the crash go away.
-            self.move_dot_with_infringement_filtering(
-                recorder,
-                joints.0.into(),
-                from.end_point(),
-                &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
-            )?;
-            self.move_dot_with_infringement_filtering(
-                recorder,
-                joints.1.into(),
-                to.end_point(),
-                &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
-            )?;
-
-            self.shift_bend_with_infringement_filtering(
-                recorder,
-                rail.into(),
-                offset,
-                &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
-            )?;
-
-            // Update offsets in case the rule conditions changed.
-
-            maybe_rail = self.primitive(rail).outer();
         }
 
         Ok(())
     }
 
+    fn update_bow(
+        &mut self,
+        recorder: &mut DrawingEdit<CW, Cel>,
+        rail: LooseBendIndex,
+    ) -> Result<(), DrawingException> {
+        let rail_primitive = self.primitive(rail);
+        let joints = rail_primitive.joints();
+        let width = rail_primitive.width();
+
+        let from_head = self.rear_head(joints.1);
+        let to_head = self.rear_head(joints.0);
+
+        let (from, to, offset) = if let Some(inner) = rail_primitive.inner() {
+            let inner = inner.into();
+            let from = self.guide_for_head_around_bend_segment(
+                &from_head,
+                inner,
+                RotationSense::Counterclockwise,
+                width,
+            )?;
+            let to = self.guide_for_head_around_bend_segment(
+                &to_head,
+                inner,
+                RotationSense::Clockwise,
+                width,
+            )?;
+            let offset = self.guide_for_head_around_bend_offset(&from_head, inner, width);
+            (from, to, offset)
+        } else {
+            let core = rail_primitive.core().into();
+            let from = self.guide_for_head_around_dot_segment(
+                &from_head,
+                core,
+                RotationSense::Counterclockwise,
+                width,
+            )?;
+            let to = self.guide_for_head_around_dot_segment(
+                &to_head,
+                core,
+                RotationSense::Clockwise,
+                width,
+            )?;
+            let offset = self.guide_for_head_around_dot_offset(&from_head, core, width);
+            (from, to, offset)
+        };
+
+        let rail_outer_bows = self.bend_outward_bows(rail);
+
+        // Commenting out these two makes the crash go away.
+        self.move_dot_with_infringement_filtering(
+            recorder,
+            joints.0.into(),
+            from.end_point(),
+            &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
+        )?;
+        self.move_dot_with_infringement_filtering(
+            recorder,
+            joints.1.into(),
+            to.end_point(),
+            &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
+        )?;
+
+        self.shift_bend_with_infringement_filtering(
+            recorder,
+            rail.into(),
+            offset,
+            &|_drawing, _infringer, infringee| rail_outer_bows.contains(&infringee),
+        )?;
+
+        Ok(())
+    }
+
     #[debug_ensures(ret.is_ok() -> self.recording_geometry_with_rtree.graph().node_count() == old(self.recording_geometry_with_rtree.graph().node_count() + 4))]
     #[debug_ensures(ret.is_ok() -> self.recording_geometry_with_rtree.graph().edge_count() >= old(self.recording_geometry_with_rtree.graph().edge_count() + 5))]
     #[debug_ensures(ret.is_err() -> self.recording_geometry_with_rtree.graph().node_count() == old(self.recording_geometry_with_rtree.graph().node_count()))]
@@ -877,11 +888,11 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
         cane: &Cane,
         face: LooseDotIndex,
     ) {
-        let maybe_outer = self.primitive(cane.bend).outer();
+        let outers = self.primitive(cane.bend).outers().collect::<Vec<_>>();
 
         // Removing a loose bend affects its outer bends.
-        if let Some(outer) = maybe_outer {
+        for outer in &outers {
-            self.reattach_bend(recorder, outer, self.primitive(cane.bend).inner());
+            self.reattach_bend(recorder, *outer, self.primitive(cane.bend).inner());
         }
 
         self.recording_geometry_with_rtree
@@ -897,7 +908,7 @@ impl<CW: Clone, Cel: Copy, R: AccessRules> Drawing<CW, Cel, R> {
         self.recording_geometry_with_rtree
             .remove_dot(recorder, cane.dot.into());
 
-        if let Some(outer) = maybe_outer {
+        for outer in outers {
             self.update_this_and_outward_bows(recorder, outer).unwrap(); // Must never fail.
         }
     }

src/drawing/gear.rs

@@ -2,26 +2,23 @@
 //
 // SPDX-License-Identifier: MIT
 
+use std::collections::VecDeque;
+
 use enum_dispatch::enum_dispatch;
-use petgraph::stable_graph::NodeIndex;
+use petgraph::{stable_graph::NodeIndex, visit::Walker};
 
 use crate::{
     drawing::{
         bend::{BendIndex, FixedBendIndex, LooseBendIndex},
         dot::FixedDotIndex,
         graph::{MakePrimitive, PrimitiveIndex},
-        primitive::{FixedBend, FixedDot, GetFirstGear, LooseBend, Primitive},
+        primitive::{FixedBend, FixedDot, LooseBend, Primitive},
         rules::AccessRules,
         Drawing,
     },
     graph::{GetPetgraphIndex, MakeRef},
 };
 
-#[enum_dispatch]
-pub trait GetNextGear: GetPetgraphIndex {
-    fn next_gear(&self) -> Option<LooseBendIndex>;
-}
-
 #[enum_dispatch(GetPetgraphIndex, MakePrimitive)]
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum GearIndex {
@@ -56,7 +53,7 @@ impl From<BendIndex> for GearIndex {
     }
 }
 
-#[enum_dispatch(GetNextGear, GetDrawing, GetPetgraphIndex)]
+#[enum_dispatch(WalkOutwards, GetOuterGears, GetDrawing, GetPetgraphIndex)]
 pub enum GearRef<'a, CW, Cel, R> {
     FixedDot(FixedDot<'a, CW, Cel, R>),
     FixedBend(FixedBend<'a, CW, Cel, R>),
@@ -73,20 +70,40 @@ impl<'a, CW, Cel, R> GearRef<'a, CW, Cel, R> {
     }
 }
 
-impl<CW, Cel, R> GetNextGear for FixedDot<'_, CW, Cel, R> {
+#[enum_dispatch]
-    fn next_gear(&self) -> Option<LooseBendIndex> {
+pub trait GetOuterGears {
-        self.first_gear()
+    // TODO: This duplicates `.outers()` methods in some other places, we need
+    // to merge them with this.
+    // TODO: Use iterator instead of vec.
+    fn outer_gears(&self) -> Vec<LooseBendIndex>;
+}
+
+#[enum_dispatch]
+pub trait WalkOutwards {
+    fn outwards(&self) -> DrawingOutwardWalker;
+}
+
+/// I found it easier to just duplicate `OutwardWalker<BI>` for `Drawing<...>`.
+pub struct DrawingOutwardWalker {
+    frontier: VecDeque<LooseBendIndex>,
+}
+
+impl DrawingOutwardWalker {
+    pub fn new(initial_frontier: impl Iterator<Item = LooseBendIndex>) -> Self {
+        let mut frontier = VecDeque::new();
+        frontier.extend(initial_frontier);
+
+        Self { frontier }
     }
 }
 
-impl<CW, Cel, R> GetNextGear for LooseBend<'_, CW, Cel, R> {
+impl<CW: Clone, Cel: Copy, R: AccessRules> Walker<&Drawing<CW, Cel, R>> for DrawingOutwardWalker {
-    fn next_gear(&self) -> Option<LooseBendIndex> {
+    type Item = LooseBendIndex;
-        self.outer()
-    }
-}
 
-impl<CW, Cel, R> GetNextGear for FixedBend<'_, CW, Cel, R> {
+    fn walk_next(&mut self, drawing: &Drawing<CW, Cel, R>) -> Option<Self::Item> {
-    fn next_gear(&self) -> Option<LooseBendIndex> {
+        let front = self.frontier.pop_front()?;
-        self.first_gear()
+        self.frontier.extend(drawing.primitive(front).outers());
+
+        Some(front)
     }
 }

src/drawing/primitive.rs

@@ -18,6 +18,8 @@ use crate::{
     graph::{GenericIndex, GetPetgraphIndex},
 };
 
+use super::gear::{DrawingOutwardWalker, GetOuterGears, WalkOutwards};
+
 pub trait GetDrawing {
     type CompoundWeight;
     type CompoundEntryLabel;
@@ -86,12 +88,14 @@ pub trait GetJoints {
     fn joints(&self) -> (Self::F, Self::T);
 }
 
-pub trait GetFirstGear: GetDrawing + GetPetgraphIndex {
+pub trait GetLowestGears: GetDrawing + GetPetgraphIndex {
-    fn first_gear(&self) -> Option<LooseBendIndex> {
+    // TODO: Make it return an iterator instead of a vec.
+    fn lowest_gears(&self) -> Vec<LooseBendIndex> {
         self.drawing()
             .geometry()
-            .first_rail(self.petgraph_index())
+            .all_rails(self.petgraph_index())
             .map(|ni| LooseBendIndex::new(ni.petgraph_index()))
+            .collect()
     }
 }
 
@@ -279,7 +283,19 @@ impl<CW, Cel, R> GetLimbs for FixedDot<'_, CW, Cel, R> {
     }
 }
 
-impl<CW, Cel, R> GetFirstGear for FixedDot<'_, CW, Cel, R> {}
+impl<CW, Cel, R> GetLowestGears for FixedDot<'_, CW, Cel, R> {}
+
+impl<CW, Cel, R> GetOuterGears for FixedDot<'_, CW, Cel, R> {
+    fn outer_gears(&self) -> Vec<LooseBendIndex> {
+        self.lowest_gears()
+    }
+}
+
+impl<CW, Cel, R> WalkOutwards for FixedDot<'_, CW, Cel, R> {
+    fn outwards(&self) -> DrawingOutwardWalker {
+        DrawingOutwardWalker::new(self.lowest_gears().into_iter())
+    }
+}
 
 pub type LooseDot<'a, CW, Cel, R> = GenericPrimitive<'a, LooseDotWeight, CW, Cel, R>;
 impl_loose_primitive!(LooseDot, LooseDotWeight);
@@ -433,8 +449,19 @@ impl<CW, Cel, R> GetJoints for FixedBend<'_, CW, Cel, R> {
     }
 }
 
-impl<CW, Cel, R> GetFirstGear for FixedBend<'_, CW, Cel, R> {}
+impl<CW, Cel, R> GetLowestGears for FixedBend<'_, CW, Cel, R> {}
-//impl<'a, R: QueryRules> GetInnerOuter for FixedBend<'a, CW, Cel, R> {}
+
+impl<CW, Cel, R> GetOuterGears for FixedBend<'_, CW, Cel, R> {
+    fn outer_gears(&self) -> Vec<LooseBendIndex> {
+        self.lowest_gears()
+    }
+}
+
+impl<CW, Cel, R> WalkOutwards for FixedBend<'_, CW, Cel, R> {
+    fn outwards(&self) -> DrawingOutwardWalker {
+        DrawingOutwardWalker::new(self.lowest_gears().into_iter())
+    }
+}
 
 pub type LooseBend<'a, CW, Cel, R> = GenericPrimitive<'a, LooseBendWeight, CW, Cel, R>;
 impl_loose_primitive!(LooseBend, LooseBendWeight);
@@ -477,6 +504,18 @@ impl<CW, Cel, R> GetJoints for LooseBend<'_, CW, Cel, R> {
     }
 }
 
+impl<CW, Cel, R> GetOuterGears for LooseBend<'_, CW, Cel, R> {
+    fn outer_gears(&self) -> Vec<LooseBendIndex> {
+        self.outers().collect()
+    }
+}
+
+impl<CW, Cel, R> WalkOutwards for LooseBend<'_, CW, Cel, R> {
+    fn outwards(&self) -> DrawingOutwardWalker {
+        DrawingOutwardWalker::new(self.outers())
+    }
+}
+
 impl<CW, Cel, R> LooseBend<'_, CW, Cel, R> {
     pub fn inner(&self) -> Option<LooseBendIndex> {
         self.drawing()
@@ -485,11 +524,10 @@ impl<CW, Cel, R> LooseBend<'_, CW, Cel, R> {
             .map(|ni| LooseBendIndex::new(ni.petgraph_index()))
     }
 
-    pub fn outer(&self) -> Option<LooseBendIndex> {
+    pub fn outers(&self) -> impl Iterator<Item = LooseBendIndex> + '_ {
         self.drawing()
             .geometry()
             .outers(self.bend_index())
-            .next()
             .map(|node| LooseBendIndex::new(node.petgraph_index()))
     }
 }

src/geometry/geometry.rs

@@ -573,15 +573,6 @@ impl<
         BI: GetPetgraphIndex,
     > Geometry<PW, DW, SW, BW, CW, Cel, PI, DI, SI, BI>
 {
-    pub fn first_rail(&self, node: NodeIndex<usize>) -> Option<BI> {
-        self.all_rails(node).find(|bend| {
-            !self
-                .graph
-                .edges_directed(bend.petgraph_index(), Incoming)
-                .any(|edge| matches!(edge.weight(), GeometryLabel::Outer))
-        })
-    }
-
     pub fn all_rails(&self, node: NodeIndex<usize>) -> impl Iterator<Item = BI> + '_ {
         self.graph
             .edges_directed(node, Incoming)

src/router/navmesh.rs

@@ -11,7 +11,8 @@ use petgraph::{
     graph::UnGraph,
     stable_graph::NodeIndex,
     visit::{
-        Data, EdgeRef, GraphBase, IntoEdgeReferences, IntoEdges, IntoNeighbors, IntoNodeIdentifiers,
+        Data, EdgeRef, GraphBase, IntoEdgeReferences, IntoEdges, IntoNeighbors,
+        IntoNodeIdentifiers, Walker,
     },
 };
 use spade::InsertionError;
@@ -21,7 +22,7 @@ use crate::{
     drawing::{
         bend::{FixedBendIndex, LooseBendIndex},
         dot::FixedDotIndex,
-        gear::{GearIndex, GetNextGear},
+        gear::{GearIndex, GetOuterGears, WalkOutwards},
         graph::{MakePrimitive, PrimitiveIndex},
         primitive::Primitive,
         rules::AccessRules,
@@ -183,8 +184,7 @@ impl Navmesh {
             } else {
                 map.insert(trianvertex, vec![]);
 
-                let mut gear =
+                let gear = Into::<GearIndex>::into(Into::<BinavnodeNodeIndex>::into(trianvertex));
-                    Into::<GearIndex>::into(Into::<BinavnodeNodeIndex>::into(trianvertex));
 
                 if options.squeeze_through_under_bends {
                     Self::add_trianvertex_to_graph_and_map_as_binavnode(
@@ -195,30 +195,34 @@ impl Navmesh {
                     );
 
                     if options.wrap_around_bands {
-                        while let Some(bend) = gear.ref_(layout.drawing()).next_gear() {
+                        let mut outwards = gear.ref_(layout.drawing()).outwards();
+                        while let Some(outward) = outwards.walk_next(layout.drawing()) {
                             Self::add_trianvertex_to_graph_and_map_as_binavnode(
                                 &mut graph,
                                 &mut map,
                                 trianvertex,
-                                bend.into(),
+                                outward.into(),
                             );
-                            gear = bend.into();
                         }
                     }
-                } else if let Some(first_bend) = gear.ref_(layout.drawing()).next_gear() {
+                } else if !gear.ref_(layout.drawing()).outer_gears().is_empty() {
-                    let mut bend = first_bend;
+                    let mut outwards = gear.ref_(layout.drawing()).outwards();
-
+                    while let Some(outward) = outwards.walk_next(layout.drawing()) {
-                    while let Some(next_bend) = gear.ref_(layout.drawing()).next_gear() {
+                        if layout
-                        bend = next_bend;
+                            .drawing()
-                        gear = bend.into();
+                            .primitive(outward)
+                            .outers()
+                            .collect::<Vec<_>>()
+                            .is_empty()
+                        {
+                            Self::add_trianvertex_to_graph_and_map_as_binavnode(
+                                &mut graph,
+                                &mut map,
+                                trianvertex,
+                                outward.into(),
+                            );
+                        }
                     }
-
-                    Self::add_trianvertex_to_graph_and_map_as_binavnode(
-                        &mut graph,
-                        &mut map,
-                        trianvertex,
-                        bend.into(),
-                    );
                 } else {
                     Self::add_trianvertex_to_graph_and_map_as_binavnode(
                         &mut graph,