Chapter 1

Slide, Intro Prolog.

Slide, Using Prolog.

Slide, Figure 1.1, facts.
Draw Figure 1.1 on board for later reference.
Write parent facts on board also for later reference.

Slide, Demo:
?- consult( ‘ch1.pl’).
?- halt. % to quit

Show ch1.pl
Demo
?- parent( bob, pat).
?- parent( liz, pat).
?- parent( tom, ben).
?- parent( X, liz).
?- parent( bob, X).
?- parent( X, Y).

; % next solution
a % all solutions

Slide, Figure 1.2.

Demo
?- parent( Y, jim), parent( X, Y).

Slide, Demo
Who are tom’s grandchildren?
?- parent( tom, X), parent( X, Y).

, is conjunction
Try reverse order, same result.

Demo trace of
?- parent( tom, X), parent( X, Y).
then work through the trace on the slides

Commands are
?- trace.
?- notrace.

Back to slide
Do ann and pat have a common parent?
?- parent( X, ann), parent( X, pat).

Slide, Bratko vs gprolog

Slide, Defining relations by rules, Figure 1.3
Demo mother
Demo grandparent

Scroll ch1.pl
Ask for definition of sister.
Try without X \=Y to see what happens.

Slide, Clause
goal, head, body

Slide, Recursive rules, Figure 1.5

Slide, Recursive rules, Figure 1.6

Slide, Recursive rules, Figure 1.7
       Rule for ancestor

Demo query
?- ancestor( tom, pat).
Show the trace.
Then work through the slide sequence.

Slide, Figure 1.9
Compare with trace of ancestor( tom, pat).