prolog and recursive descent parsing?

How does prolog use recursive descent parsing to solve problems given
to it?. Does it make a graph of the parse tree or something?


I've only encountered recursive descent parsing to solve problems like
boolean algebra or number arithmetic but prolog can do much more than
this.


I understand that it's easy enough to do for facts like.


male(bill).
female(mary).


one only has to compare the query to the facts in the database per
token. but what about rules like?


parent(X,Y):-mother(X,Y).
grandparent(X,Y):-parent(X,Z),parent(Z,Y).


I find it difficult to imagine that you would only check them per
token.


So, how does prolog handle this?

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