# ============================================================================ # RESTdesc restaurant finder — ARC style service composition example. # Based on the RestoProof [1] idea of describing hypermedia APIs as N3 rules. # # This example starts with only a person and a desired dinner date. A chain of # RESTdesc-style service descriptions first finds the person's address, then a # location, then today's weather, then a suitable restaurant, and finally a # reservation. The ARC report explains the result in plain language and checks # that the reservation really preserves the requested date and outdoor seating # preference. # # [1] https://github.com/RESTdesc/RestoProof # ============================================================================ @prefix : . @prefix http: . @prefix foaf: . @prefix con: . @prefix geo: . @prefix meteo: . @prefix resto: . @prefix string: . @prefix log: . # ---------------- # Initial question # ---------------- :Ruben a foaf:Person. :PlanningDocument a foaf:Document. :DinnerPlan resto:hasDate "2026-04-08"; resto:isOn :appointmentList. # ----------------------------------- # RESTdesc-style service descriptions # ----------------------------------- # Preferences API: from person + document to address. { :Ruben a foaf:Person. :PlanningDocument a foaf:Document. } => { :reqPreferences http:methodName "GET"; http:requestURI :preferencesEndpoint; http:resp :respPreferences. :respPreferences http:body :GentAddress. :Ruben foaf:based_near :GentAddress. :GentAddress a con:Address; resto:label "Gent". }. # Location API: from address to geo point. { :GentAddress a con:Address. } => { :reqLocation http:methodName "GET"; http:requestURI :locationEndpoint; http:resp :respLocation. :respLocation http:body :GentPoint. :GentPoint a geo:Point; geo:lat "51.05"; geo:long "3.72". }. # Temperature API: from point to temperature. { :GentPoint a geo:Point. } => { :reqTemperature http:methodName "GET"; http:requestURI :temperatureEndpoint; http:resp :respTemperature. :respTemperature http:body :Temp22. :GentPoint meteo:temperature :Temp22. :Temp22 meteo:celsius "22". }. # Pressure API: from point to pressure. { :GentPoint a geo:Point. } => { :reqPressure http:methodName "GET"; http:requestURI :pressureEndpoint; http:resp :respPressure. :respPressure http:body :Pressure1016. :GentPoint meteo:pressure :Pressure1016. :Pressure1016 meteo:millibar "1016". }. # Weather interpretation: mild temperature + stable pressure => outdoor dining. { :GentPoint meteo:temperature :Temp22; meteo:pressure :Pressure1016. :Temp22 meteo:celsius "22". :Pressure1016 meteo:millibar "1016". } => { :TodayWeather resto:mildTemperature true; resto:stableWeather true; resto:goodForOutsideSeating true. :DesiredPlace resto:isOutside true; resto:label "outside terrace". }. # Appointment API: from location + weather + date to a suitable restaurant. { :GentPoint a geo:Point. :TodayWeather resto:goodForOutsideSeating true. :DinnerPlan resto:isOn :appointmentList; resto:hasDate ?Date. } => { :reqRecommendation http:methodName "POST"; http:requestURI :appointmentList; http:body :DinnerPlan; http:resp :respRecommendation. :respRecommendation http:body :DinnerPlan. :DinnerPlan resto:isAt :Maximiliaan. :Maximiliaan a resto:Restaurant; resto:name "Maximiliaan"; resto:reservationList :MaximiliaanReservations. }. # Restaurant API: from restaurant + desired place + date to a reservation. { :Maximiliaan resto:reservationList :MaximiliaanReservations. :DesiredPlace resto:isOutside ?Outside. :DinnerPlan resto:hasDate ?Date. } => { :reqReservation http:methodName "POST"; http:requestURI :MaximiliaanReservations; http:body :DinnerPlan; http:resp :respReservation. :respReservation http:body :Reservation42. :Maximiliaan resto:hasReservation :Reservation42. :Reservation42 resto:onDate ?Date; resto:place :TableArea42. :TableArea42 resto:isOutside ?Outside. }. # Goal shape, in the style of the original RestoProof query. { ?Restaurant resto:hasReservation ?Reservation. ?Reservation resto:onDate ?Date; resto:place ?Place. ?Place resto:isOutside ?Outside. } => { :Goal resto:restaurant ?Restaurant; resto:reservation ?Reservation; resto:onDate ?Date; resto:isOutside ?Outside. }. # ---------------- # Reason-why facts # ---------------- { :Goal resto:restaurant ?Restaurant; resto:onDate ?Date; resto:isOutside true. ?Restaurant resto:name ?Name. } => { :Decision :outcome "A restaurant was found and reserved."; :restaurantName ?Name; :reservationDate ?Date; :seating "outside terrace". }. # ------------------ # Independent checks # ------------------ { :Ruben foaf:based_near :GentAddress. :GentAddress a con:Address. } => { :Check :c1 "OK - the preferences service resolved the person's address." }. { :GentPoint a geo:Point; geo:lat "51.05"; geo:long "3.72". } => { :Check :c2 "OK - the location service turned the address into map coordinates." }. { :GentPoint meteo:temperature :Temp22; meteo:pressure :Pressure1016. :Temp22 meteo:celsius "22". :Pressure1016 meteo:millibar "1016". } => { :Check :c3 "OK - the weather services supplied temperature and pressure for that location." }. { :TodayWeather resto:mildTemperature true; resto:stableWeather true; resto:goodForOutsideSeating true. } => { :Check :c4 "OK - the weather interpretation justified outdoor seating." }. { :DinnerPlan resto:isAt :Maximiliaan. :Maximiliaan a resto:Restaurant; resto:reservationList :MaximiliaanReservations. } => { :Check :c5 "OK - the recommendation step selected a restaurant that can accept reservations." }. { :DinnerPlan resto:hasDate ?Requested. :Reservation42 resto:onDate ?Actual. ?Requested log:equalTo ?Actual. } => { :Check :c6 "OK - the reservation preserved the requested dinner date." }. { :DesiredPlace resto:isOutside ?Wanted. :TableArea42 resto:isOutside ?Actual. ?Wanted log:equalTo ?Actual. } => { :Check :c7 "OK - the reservation preserved the outdoor seating preference." }. { :Goal resto:restaurant :Maximiliaan; resto:reservation :Reservation42; resto:isOutside true. } => { :Check :c8 "OK - the final goal pattern from the original RESTdesc query is satisfied." }. # Fail loudly on the two key integrity conditions. { :DinnerPlan resto:hasDate ?Requested. :Reservation42 resto:onDate ?Actual. ?Requested log:notEqualTo ?Actual. } => false. { :DesiredPlace resto:isOutside ?Wanted. :TableArea42 resto:isOutside ?Actual. ?Wanted log:notEqualTo ?Actual. } => false. # Also fail loudly if any expected check is missing once a decision exists. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. :Check :c4 ?C4. :Check :c5 ?C5. :Check :c6 ?C6. :Check :c7 ?C7. 1 log:notIncludes { :Check :c8 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. :Check :c4 ?C4. :Check :c5 ?C5. :Check :c6 ?C6. 1 log:notIncludes { :Check :c7 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. :Check :c4 ?C4. :Check :c5 ?C5. 1 log:notIncludes { :Check :c6 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. :Check :c4 ?C4. 1 log:notIncludes { :Check :c5 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. 1 log:notIncludes { :Check :c4 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. :Check :c2 ?C2. 1 log:notIncludes { :Check :c3 ?Any. }. } => false. { :Decision :outcome ?Outcome. :Check :c1 ?C1. 1 log:notIncludes { :Check :c2 ?Any. }. } => false. { :Decision :outcome ?Outcome. 1 log:notIncludes { :Check :c1 ?Any. }. } => false. # ---------- # ARC report # ---------- { :Decision :outcome ?Outcome; :restaurantName ?RestaurantName; :reservationDate ?Date; :seating ?Seating. :Check :c1 ?C1. :Check :c2 ?C2. :Check :c3 ?C3. :Check :c4 ?C4. :Check :c5 ?C5. :Check :c6 ?C6. :Check :c7 ?C7. :Check :c8 ?C8. ( "RESTdesc — Restaurant finder\n\n" "Answer\n" ?Outcome "\n" "Restaurant: " ?RestaurantName "\n" "Date: " ?Date "\n" "Seating: " ?Seating "\n\n" "Reason Why\n" "The plan resolved the person's address, turned it into a map point, checked the local weather, selected a suitable restaurant, and then created a reservation. " "Because the weather came back mild and stable (22 C and 1016 mbar), the chosen seating stayed outdoors.\n\n" "Check\n" "C1 " ?C1 "\n" "C2 " ?C2 "\n" "C3 " ?C3 "\n" "C4 " ?C4 "\n" "C5 " ?C5 "\n" "C6 " ?C6 "\n" "C7 " ?C7 "\n" "C8 " ?C8 "\n" ) string:concatenation ?Block. } => { :Report log:outputString ?Block. }.