Refactor AppendGraph iterators into one RawIncidenceIterator

src/models/append_graph.rs

@@ -23,35 +23,19 @@ struct IncidenceEntry {
     adjacent: Vertex,
 }
 
-struct AdjacentVertexIterator<'a> {
+struct RawIncidenceIterator<'a> {
     graph: &'a AppendGraph,
     incidence: Option<Incidence>,
 }
 
-impl<'a> Iterator for AdjacentVertexIterator<'a> {
-    type Item = Vertex;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let current = self.incidence?;
-        let entry = &self.graph.incidences[current.0];
-        self.incidence = entry.next;
-        Some(entry.adjacent)
-    }
-}
-
-struct IncidenceIterator<'a> {
-    graph: &'a AppendGraph,
-    incidence: Option<Incidence>,
-}
-
-impl<'a> Iterator for IncidenceIterator<'a> {
+impl<'a> Iterator for RawIncidenceIterator<'a> {
     type Item = (Vertex, Incidence);
 
     fn next(&mut self) -> Option<Self::Item> {
         let current = self.incidence?;
         let entry = &self.graph.incidences[current.0];
         self.incidence = entry.next;
-        Some((entry.adjacent, current.normalize()))
+        Some((entry.adjacent, current))
     }
 }
 
@@ -129,10 +113,11 @@ impl GraphTopology for AppendGraph {
     }
 
     fn adjacent_vertices(&self, v: Self::Vertex) -> impl Iterator<Item = Self::Vertex> {
-        AdjacentVertexIterator {
+        RawIncidenceIterator {
             graph: self,
             incidence: self.vertices[v.0].first_incidence,
         }
+        .map(|(v, _)| v)
     }
 
     fn edges(&self) -> impl Iterator<Item = Self::Edge> {
@@ -140,10 +125,11 @@ impl GraphTopology for AppendGraph {
     }
 
     fn incidences(&self, v: Self::Vertex) -> impl Iterator<Item = (Self::Vertex, Self::Edge)> {
-        IncidenceIterator {
+        RawIncidenceIterator {
             graph: self,
             incidence: self.vertices[v.0].first_incidence,
         }
+        .map(|(v, e)| (v, e.normalize()))
     }
 
     fn add_vertex(&mut self) -> Self::Vertex {