# ===========================================================================
# French cities — ARC style graph reachability example.
# Based on https://raw.githubusercontent.com/eyereasoner/eyeling/refs/heads/main/examples/french-cities.n3
#
# This example shows how simple graph rules can answer a practical travel-style
# question: which cities can reach Nantes by following one-way connections?
# The program derives longer paths from shorter ones, explains why the answer is
# correct, and checks the key steps independently.
# ===========================================================================

@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix string: <http://www.w3.org/2000/10/swap/string#>.
@prefix : <https://example.org/french-cities#>.

# ---------------------------------------------------------------------------
# Facts
# ---------------------------------------------------------------------------

:paris    :oneway :orleans.
:paris    :oneway :chartres.
:paris    :oneway :amiens.
:orleans  :oneway :blois.
:orleans  :oneway :bourges.
:blois    :oneway :tours.
:chartres :oneway :lemans.
:lemans   :oneway :angers.
:lemans   :oneway :tours.
:angers   :oneway :nantes.

:oneway rdfs:subPropertyOf :path.
:path a owl:TransitiveProperty.

:paris    :label "Paris".
:chartres :label "Chartres".
:lemans   :label "Le Mans".
:angers   :label "Angers".
:nantes   :label "Nantes".

# ---------------------------------------------------------------------------
# RDFS / OWL rules from the original example
# ---------------------------------------------------------------------------

{ ?P rdfs:subPropertyOf ?Q.
  ?S ?P ?O. }
    => { ?S ?Q ?O. }.

{ ?P rdfs:subPropertyOf ?Q.
  ?Q rdfs:subPropertyOf ?R. }
    => { ?P rdfs:subPropertyOf ?R. }.

{ ?P a owl:TransitiveProperty.
  ?S ?P ?X.
  ?X ?P ?O. }
    => { ?S ?P ?O. }.

# ---------------------------------------------------------------------------
# ARC logic
# ---------------------------------------------------------------------------

{ ?C :path :nantes. }
    => { ?C :canReach :nantes. }.

{ :paris    :canReach :nantes. }
    => { :report :reachableCity :paris. }.

{ :chartres :canReach :nantes. }
    => { :report :reachableCity :chartres. }.

{ :lemans   :canReach :nantes. }
    => { :report :reachableCity :lemans. }.

{ :angers   :canReach :nantes. }
    => { :report :reachableCity :angers. }.

{ :report :reachableCity :paris, :chartres, :lemans, :angers. }
    => { :report :outcome
        "Four cities in this small network can reach Nantes: Paris, Chartres, Le Mans, and Angers.". }.

# Independent check facts

{ :angers :oneway :nantes. }
    => { :check :c1 "OK - Angers has a direct one-way connection to Nantes.". }.

{ :lemans :oneway :angers.
  :angers :path :nantes. }
    => { :check :c2 "OK - Le Mans reaches Nantes by chaining Le Mans → Angers → Nantes.". }.

{ :chartres :oneway :lemans.
  :lemans :path :nantes. }
    => { :check :c3 "OK - Chartres reaches Nantes by chaining Chartres → Le Mans → Angers → Nantes.". }.

{ :paris :oneway :chartres.
  :chartres :path :nantes. }
    => { :check :c4 "OK - Paris reaches Nantes by chaining Paris → Chartres → Le Mans → Angers → Nantes.". }.

{ :orleans :path :nantes. }
    => false.

{ :amiens :path :nantes. }
    => false.

{ :bourges :path :nantes. }
    => false.

{ :blois :path :nantes.
  :blois log:notEqualTo :nantes. }
    => false.

{ :tours :path :nantes.
  :tours log:notEqualTo :nantes. }
    => false.

{ :report :reachableCity ?C.
  ?C :label ?L. }
    => { ?C :reachableLabel ?L. }.

# ---------------------------------------------------------------------------
# ARC output
# ---------------------------------------------------------------------------

{ :report :outcome ?Outcome.
  :paris :reachableLabel ?Paris.
  :chartres :reachableLabel ?Chartres.
  :lemans :reachableLabel ?LeMans.
  :angers :reachableLabel ?Angers.
  :check :c1 ?C1; :c2 ?C2; :c3 ?C3; :c4 ?C4.
  (
    "French cities — ARC style graph reachability\n\n"
    "Answer\n"
    ?Outcome "\n\n"
    "Reason Why\n"
    "The original example says that every :oneway link is also a :path, and that :path is transitive. "
    "So once Angers can reach Nantes directly, longer routes can be built by chaining earlier links. "
    ?Angers " reaches Nantes directly. "
    ?LeMans " reaches Nantes through Angers. "
    ?Chartres " reaches Nantes through Le Mans and Angers. "
    ?Paris " reaches Nantes through Chartres, Le Mans, and Angers.\n\n"
    "Check\n"
    "C1 " ?C1 "\n"
    "C2 " ?C2 "\n"
    "C3 " ?C3 "\n"
    "C4 " ?C4 "\n"
    "C5 OK - cities without a chain to Nantes are rejected by fail-loud fuse rules.\n"
  ) string:concatenation ?Block. }
    => { :report log:outputString ?Block. }.