gdsl 0.2.1

GDSL is a graph data-structure library including graph containers, connected node strutures and efficient algorithms on those structures. Nodes are independent of a graph container and can be used as connected smart pointers.
Documentation 
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use super::*;
use std::{fmt::Display, hash::Hash, ops::Index};

pub fn backtrack_edge_tree<K, N, E>(edge_tree: Vec<Edge<K, N, E>>) -> Vec<Edge<K, N, E>>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    let mut path = Vec::new();

    if edge_tree.len() == 1 {
        path.push(edge_tree[0].clone());
        return path;
    }
    let w = edge_tree.last().unwrap();
    path.push(w.clone());
    let mut i = 0;
    for edge in edge_tree.iter().rev() {
        let Edge(_, v, _) = edge;
        let Edge(s, _, _) = &path[i];
        if s == v {
            path.push(edge.clone());
            i += 1;
        }
    }
    path.reverse();
    path
}

pub struct Path<K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    pub edges: Vec<Edge<K, N, E>>,
}

impl<K, N, E> Path<K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    pub fn len(&self) -> usize {
        // Conceptually a path always contains at least one node,
        // the root node. The path containes edges, so the length
        // of the path is the number of edges plus one.
        self.edges.len() + 1
    }

    pub fn from_edge_tree(edge_tree: Vec<Edge<K, N, E>>) -> Path<K, N, E> {
        Path {
            edges: backtrack_edge_tree(edge_tree),
        }
    }

    pub fn iter_nodes(&self) -> PathNodeIterator<K, N, E> {
        PathNodeIterator {
            path: self,
            position: 0,
        }
    }

    pub fn iter_edges(&self) -> PathEdgeIterator<K, N, E> {
        PathEdgeIterator {
            path: self,
            position: 0,
        }
    }

    pub fn first_edge(&self) -> Option<&Edge<K, N, E>> {
        self.edges.first()
    }

    pub fn first_node(&self) -> Option<&Node<K, N, E>> {
        self.edges.first().map(|e| &e.1)
    }

    pub fn last_edge(&self) -> Option<&Edge<K, N, E>> {
        self.edges.last()
    }

    pub fn last_node(&self) -> Option<&Node<K, N, E>> {
        self.edges.last().map(|e| &e.1)
    }

    pub fn to_vec_nodes(&self) -> Vec<Node<K, N, E>> {
        self.iter_nodes().collect()
    }

    pub fn to_vec_edges(&self) -> Vec<Edge<K, N, E>> {
        self.edges.clone()
    }
}

impl<K, N, E> Index<usize> for Path<K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    type Output = Edge<K, N, E>;

    fn index(&self, index: usize) -> &Self::Output {
        &self.edges[index]
    }
}

pub struct PathEdgeIterator<'a, K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    path: &'a Path<K, N, E>,
    position: usize,
}

impl<'a, K, N, E> Iterator for PathEdgeIterator<'a, K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    type Item = Edge<K, N, E>;

    fn next(&mut self) -> Option<Self::Item> {
        match self.path.edges.get(self.position) {
            Some(edge) => {
                self.position += 1;
                Some(Edge(edge.0.clone(), edge.1.clone(), edge.2.clone()))
            }
            None => None,
        }
    }
}

pub struct PathNodeIterator<'a, K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    path: &'a Path<K, N, E>,
    position: usize,
}

impl<'a, K, N, E> Iterator for PathNodeIterator<'a, K, N, E>
where
    K: Clone + Hash + Display + PartialEq + Eq,
    N: Clone,
    E: Clone,
{
    type Item = Node<K, N, E>;

    fn next(&mut self) -> Option<Self::Item> {
        if self.position == 0 {
            match self.path.edges.get(self.position) {
                Some(edge) => {
                    self.position += 1;
                    return Some(edge.0.clone());
                }
                None => return None,
            }
        }
        match self.path.edges.get(self.position - 1) {
            Some(edge) => {
                self.position += 1;
                Some(edge.1.clone())
            }
            None => None,
        }
    }
}