This is the knapsack example taken from:
http://www.ise.gmu.edu/~duminda/classes/fall03/set3.ppt starting on page 19
This uses backward-chaining to solve the knapsack problem (see link above).
The top-level goal is:
legal_knapsack($Pantry, $Capacity, $Knapsack)
$Pantry is a tuple of food items. Each food item is: (name, weight,
$Capacity is the maximum weight capacity of the knapsack.
$Knapsack is a subset of $Pantry whose total weight is <= $Capacity.
Uses the legal_knapsack goal to enumerate all of the possible
knapsacks within the stated capacity. Returns the total_calories and
knapsack of the answer with most calories.
The final example on page 36 at the site above would be:
>>> from examples.knapsack import test