knowledge base LINKS2. This is like LINKS, but instead of
describing just one straight chain, it describes a tree-like network.
As before, you have clauses for
goes_to(X,Y) if X leads to Y, but now
X may have more than one successor.
You also have clauses for
weight(X,W), where X is a square and W is a
numerical weight associated with it. The idea is that squares with the
lowest weights define a preferred route. Your job is to write a
look, but it has to take the lowest-weight successor at
This is not as hard as it sounds. First, assume you have a predicate
best(X,Y) which, given square X, returns the lowest-weight successor
in Y. If you have this, you can easily write
look, just by copying the
code in the lesson.
So how do you write
best? Look back at the end of Supplement 6. This
should give you enough information.