ch18ex01.pro

prolog,人工智能推理程序,运行环境prolog

/*
   Turbo Prolog 2.0 Chapter 18, Example Program 1
   
   Copyright (c) 1986, 88 by Borland International, Inc

*/

database
   xpositive(symbol, symbol)
   xnegative(symbol, symbol)
      
predicates
   animal_is(symbol)
   it_is(symbol)
   ask(symbol, symbol, symbol)
   remember(symbol, symbol, symbol)
   positive(symbol, symbol)
   negative(symbol, symbol)
   clear_facts
   run
   
clauses
   animal_is(cheetah) :- it_is(mammal),
      it_is(carnivore),
      positive(has, tawny_color),
      positive(has, dark_spots).

   animal_is(tiger) :- it_is(mammal),
      it_is(carnivore),
      positive(has, tawny_color),
      positive(has, black_stripes).

   animal_is(giraffe) :- it_is(ungulate),
      positive(has, long_neck),
      positive(has, long_legs),
      positive(has, dark_spots).

   animal_is(zebra) :- it_is(ungulate), positive(has,black_stripes).

   animal_is(ostrich) :- it_is(bird),
      negative(does, fly),
      positive(has, long_neck),
      positive(has, long_legs),
      positive(has, black_and_white_color).

   animal_is(penguin) :- it_is(bird),
      negative(does, fly),
      positive(does, swim),
      positive(has, black_and_white_color).

   animal_is(albatross) :-
     it_is(bird),  positive(does, fly_well).
      it_is(mammal) :- positive(has, hair).
      it_is(mammal) :- positive(does, give_milk).
      it_is(bird)   :- positive(has, feathers).
      it_is(bird)   :- positive(does, fly), positive(does,lay_eggs).

      it_is(carnivore) :- positive(does, eat_meat).

      it_is(carnivore) :-
         positive(has, pointed_teeth),
         positive(has, claws),
         positive(has, forward_eyes).

      it_is(ungulate) :-
         it_is(mammal), positive(has, hooves).

      it_is(ungulate) :- 
        it_is(mammal), positive(does, chew_cud).

   positive(X, Y) :-
      xpositive(X, Y), !.
   positive(X, Y) :-
      not(xnegative(X, Y)),
      ask(X, Y, yes).

   negative(X, Y) :-
      xnegative(X, Y), !.
   negative(X, Y) :-
      not(xpositive(X, Y)),
      ask(X, Y, no).

   ask(X, Y, yes) :-
      !, write(X, " it ", Y, '\n'),
      readln(Reply),
      frontchar(Reply,  'y', _),
      remember(X, Y, yes).
   ask(X, Y, no) :-
      !, write(X, " it ", Y, '\n'),
      readln(Reply),
      frontchar(Reply, 'n', _),
      remember(X, Y, no).

   remember(X, Y, yes) :- assertz(xpositive(X,Y)).
   remember(X, Y, no)  :- assertz(xnegative(X,Y)).

   clear_facts :- 
      write("\n\nPlease press the space bar to exit\n"),
      retractall(_, dbasedom), readchar(_).

   run :-
      animal_is(X), !,
      write("\nYour animal may be a (an) ",X),
      nl, nl, clear_facts.
   run :-
      write("\nUnable to determine what"),
      write("your animal is.\n\n"), clear_facts.