fn traverse_unvisited(
    start: NodeIndex,
    eg: &EulerGraph,
    visited: &mut HashSet<EdgeIndex>,
) -> Vec<EdgeIndex> {
    let mut n = start;
    let mut traversal: Vec<EdgeIndex> = vec![];
    loop {
        // Find the straightest edge that hasn't yet been traversed.
        let e_ref = {
            let mut untraversed_edges = eg.edges(n).filter(|e_ref| !visited.contains(&e_ref.id()));

            let init_e_ref = untraversed_edges
                .next()
                .expect("expected a strongly connected euler graph");

            match traversal
                .last()
                .map(|e| eg.raw_edges()[e.index()].source())
                .map(|n| eg[n].position)
            {
                // If this is the first edge in the traversal, use the first ref.
                None => init_e_ref,

                // Retrieve the three positions used to determine the angle.
                Some(prev_source_p) => {
                    let source_p = eg[init_e_ref.source()].position;
                    let target_p = eg[init_e_ref.target()].position;
                    let init_dist = straight_angle_variance(prev_source_p, source_p, target_p);
                    let init = (init_e_ref, init_dist);
                    let (e_ref, _) = untraversed_edges.fold(init, |best, e_ref| {
                        let (_, best_dist) = best;
                        let target_p = eg[e_ref.target()].position;
                        let dist = straight_angle_variance(prev_source_p, source_p, target_p);
                        if dist < best_dist {
                            (e_ref, dist)
                        } else {
                            best
                        }
                    });
                    e_ref
                }
            }
        };

        // Add the edge into our visitation record.
        let e = e_ref.id();
        n = e_ref.target();
        visited.insert(e);
        traversal.push(e);

        // If this edge brings us back to the start, we have finished this traversal.
        if e_ref.target() == start {
            break;
        }
    }

    traversal
}
// A traversal through unvisited edges of the graph starting from `n`.
//
// Traversal ends when `n` is reached again.
//
// The returned `Vec` contains the index of each edge traversed.
A traversal through unvisited edges of the graph starting from `n`.
Traversal ends when `n` is reached again.

The returned `Vec` contains the index of each edge traversed.
A traversal through unvisited edges of the graph starting from ` n ` . Traversal ends when ` n ` is reached again . The returned ` Vec ` contains the index of each edge traversed .
fn traverse_unvisited(
    start: NodeIndex,
    eg: &EulerGraph,
    visited: &mut HashSet<EdgeIndex>,
) -> Vec<EdgeIndex> {
    let mut n = start;
    let mut traversal: Vec<EdgeIndex> = vec![];
    loop {
        // Find the straightest edge that hasn't yet been traversed.
        let e_ref = {
            let mut untraversed_edges = eg.edges(n).filter(|e_ref| !visited.contains(&e_ref.id()));
            let init_e_ref = untraversed_edges
                .next()
                .expect("expected a strongly connected euler graph");
            match traversal
                .last()
                .map(|e| eg.raw_edges()[e.index()].source())
                .map(|n| eg[n].position)
            {
                // If this is the first edge in the traversal, use the first ref.
                None => init_e_ref,
                // Retrieve the three positions used to determine the angle.
                Some(prev_source_p) => {
                    let source_p = eg[init_e_ref.source()].position;
                    let target_p = eg[init_e_ref.target()].position;
                    let init_dist = straight_angle_variance(prev_source_p, source_p, target_p);
                    let init = (init_e_ref, init_dist);
                    let (e_ref, _) = untraversed_edges.fold(init, |best, e_ref| {
                        let (_, best_dist) = best;
                        let target_p = eg[e_ref.target()].position;
                        let dist = straight_angle_variance(prev_source_p, source_p, target_p);
                        if dist < best_dist {
                            (e_ref, dist)
                        } else {
                            best
                        }
                    });
                    e_ref
                }
            }
        };
        // Add the edge into our visitation record.
        let e = e_ref.id();
        n = e_ref.target();
        visited.insert(e);
        traversal.push(e);
        // If this edge brings us back to the start, we have finished this traversal.
        if e_ref.target() == start {
            break;
        }
    }
    traversal
}
fn traverse_unvisited ( start : NodeIndex , eg : & EulerGraph , visited : & mut HashSet < EdgeIndex > , ) -> Vec < EdgeIndex > { let mut n = start ; let mut traversal : Vec < EdgeIndex > = vec ! [ ] ; loop { // Find the straightest edge that hasn't yet been traversed. let e_ref = { let mut untraversed_edges = eg . edges ( n ) . filter ( | e_ref | ! visited . contains ( & e_ref . id ( ) ) ) ; let init_e_ref = untraversed_edges . next ( ) . expect ( " " ) ; match traversal . last ( ) . map ( | e | eg . raw_edges ( ) [ e . index ( ) ] . source ( ) ) . map ( | n | eg [ n ] . position ) { // If this is the first edge in the traversal, use the first ref. None => init_e_ref , // Retrieve the three positions used to determine the angle. Some ( prev_source_p ) => { let source_p = eg [ init_e_ref . source ( ) ] . position ; let target_p = eg [ init_e_ref . target ( ) ] . position ; let init_dist = straight_angle_variance ( prev_source_p , source_p , target_p ) ; let init = ( init_e_ref , init_dist ) ; let ( e_ref , _ ) = untraversed_edges . fold ( init , | best , e_ref | { let ( _ , best_dist ) = best ; let target_p = eg [ e_ref . target ( ) ] . position ; let dist = straight_angle_variance ( prev_source_p , source_p , target_p ) ; if dist < best_dist { ( e_ref , dist ) } else { best } } ) ; e_ref } } } ; // Add the edge into our visitation record. let e = e_ref . id ( ) ; n = e_ref . target ( ) ; visited . insert ( e ) ; traversal . push ( e ) ; // If this edge brings us back to the start, we have finished this traversal. if e_ref . target ( ) == start { break ; } } traversal }
A traversal through unvisited edges of the graph starting from `n`.
A traversal through unvisited edges of the graph starting from ` n ` .
start
NodeIndex
eg
&EulerGraph
visited
&mut HashSet<EdgeIndex>
start
NodeIndex
eg
&EulerGraph
visited
&mut HashSet<EdgeIndex>