Trait Topology 

pub trait Topology {
    // Required method
    fn allowed(&self, from: usize, to: usize) -> Result<bool>;
}

Trait for defining conditional connectivity between nodes.

Topology allows you to dynamically control which connections are allowed in a mesh. This enables features like one-way passages, conditional doors, or state-dependent pathfinding.

Use Cases

• One-way passages (allow movement from A→B but not B→A)
• Doors that can open/close based on game state
• Conditional gates requiring keys or other conditions
• Dynamic environments where connectivity changes over time

Example

use shortestpath::mesh_topo::Topology;

// A topology that only allows movement in increasing index order (one-way)
struct OneWayTopology;

impl Topology for OneWayTopology {
    fn allowed(&self, from: usize, to: usize) -> Result<bool, shortestpath::Error> {
        Ok(to > from) // Only allow moving to higher indices
    }
}

Required Methods

fn allowed(&self, from: usize, to: usize) -> Result<bool>

Checks if movement from one node to another is allowed.

Arguments

• from - The index of the source node
• to - The index of the destination node

Returns

Ok(true) if the connection is allowed, Ok(false) if blocked, or an Err if there’s an error checking the topology

Implementors

impl Topology for TopologyBool