Following is a demo of the Picnic Belief Revision program.
This scenario models belief revision when the forecast is 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 looks good for a picnic later... The forecast has a temperature of 73° with sunny conditions, 48° dewpoints, and 4 MPH winds with a 22% chance of precipitation. It is now time for the picnic... Walking outside, the weather still looks good for a picnic... It is currently sunny with mild temperatures, no humidity, and calm winds The weather turned out to be great for the picnic, so you decide to go and have one! However... You arrive to find the park swarming with several orangutans that escaped from the zoo, so you can't have your picnic :( true