Module multi_hop 

Multi-hop rule resolution with loop detection for the IPFRS distributed logic engine.

This module extends distributed backward chaining with multi-hop traversal across peer nodes, tracking which (peer_id, goal_hash) pairs have been visited to prevent infinite loops in circular rule configurations.

Overview

The central entry point is MultiHopResolver::resolve, which:

1. Attempts local KB resolution (facts + one rule level) first.
2. On failure, discovers remote peers via the find_providers callback.
3. Delegates the goal to each peer via remote_query, recording each hop in a HopTrace.
4. Returns a MultiHopResult indicating whether the goal was resolved, the full hop trace, and any top-level variable bindings.

Loop detection is handled by VisitedSet: before each local or remote attempt the (peer_id, goal_hash) pair is inserted; if it already exists the attempt is skipped and false is returned immediately.

Structs

HopRecord

Records one hop in a multi-hop derivation chain.

HopTrace

Complete trace of all hops taken during a multi-hop resolution attempt.

MultiHopConfig

Configuration governing multi-hop resolution behaviour.

MultiHopResolver

Multi-hop backward-chaining resolver with loop detection.

MultiHopResult

Result of a multi-hop resolution attempt.

VisitedSet

Tracks which (peer_id, goal_hash) pairs have been visited to prevent loops.