Following is a demo of the Picnic Belief Revision program.
This scenario models belief revision when the forecast is not favorable for a picnic.
?- picnic. Walking outside, the current weather looks good for a picnic later... It is currently sunny with mild temperatures, no humidity, and calm winds The current forecast does not look good for a picnic later... The forecast has a temperature of 95° with overcast conditions, 64° dewpoints, and 4 MPH winds with a 10% chance of precipitation. The weather did not turn out so great for the picnic, so you decided to just stay home true