predicates
    nondeterm store(symbol,symbol, symbol, integer)
    nondeterm commodity_in_store(symbol, symbol,integer)
    nondeterm location_commodity(symbol, symbol)
    nondeterm can_buy(symbol,integer)
    nondeterm get_commodity(symbol,symbol,integer)
    nondeterm category_of_commodities(symbol,symbol)
    nondeterm find_commodity(symbol,integer,integer)
clauses
    can_buy(Food, Cash) :- commodity_in_store(_,Food,Price) and Cash>=Price.
    location_commodity(Shop,Food) :- store(Shop,_,Food,_).
    get_commodity(Shop,Commodity, Price) :- commodity_in_store(Shop,Food,  P_price) and P_price<=Price.
    category_of_commodities(Category,Commodity) :- store(_,Category,Commodity,_).
    find_commodity(Food,Quantity,Price) :- commodity_in_store(_,Food,P_Price) and store(_,_,Food,Q_Quantity) and P_Price<=Price and Q_Quantity<=Quantity.

    store("Bystronom", "meat section", "brisket",5).
    store("Bystronom", "meat section","forcemeat",4).
    store("Maria-Ra", "fruit","bananas",10).
    store("Bystronom", "fruit","bananas",15).
    commodity_in_store("Bystronom","bananas",80).
    commodity_in_store("Maria-Ra","bananas",43).

goal
    /*location_commodity(Where,"bananas").*/
    /*get_commodity(Where,"bananas", 45).*/
    /*can_buy(What, 70).*/
    /*category_of_commodities("fruit",What).*/
    /*store(X,Y,Z,N).*/
    find_commodity("bananas",11,45).