Traveling by car, train, and plane
We are given the following knowledge base of travel information:
byCar(auckland,hamilton).
byCar(hamilton,raglan).
byCar(valmont,saarbruecken).
byCar(valmont,metz).
byTrain(metz,frankfurt).
byTrain(saarbruecken,frankfurt).
byTrain(metz,paris).
byTrain(saarbruecken,paris).
byPlane(frankfurt,bangkok).
byPlane(frankfurt,singapore).
byPlane(paris,losAngeles).
byPlane(bangkok,auckland).
byPlane(losAngeles,auckland).
Download knowledge base.
Write a predicate travel/2 which determines
whether it is possible to travel from one place to another by
'chaining together' car, train, and plane journeys. For
example, your program should answer yes to the
query travel(valmont,raglan).
Hint
So, by using travel/2 to query the above database,
you can find out that it is possible to go from Valmont to
Raglan. In case you are planning a travel, that's already very
good information, but what you would then really want to know is
how exactly to get from Valmont to Raglan. Write a predicate
travel/3 which tells you how to travel from one
place to another. The program should, e.g., answer
yes to the query
travel(valmont,paris,go(valmont,metz,go(metz,paris)))
and X =
go(valmont,metz,go(metz,paris,go(paris,losAngeles))) to
the query travel(valmont,losAngeles,X).
Hint
Extend the predicate travel/3 so that it not only
tells you via which other cities you have to go to get from one
place to another, but also how (i.e. by car, train, or plane)
you get from one city to the next.
Hint