结果不是与给定的事实进行比较

Question

使用prolog创建一个代码来获得一些比较输出，但有些输出不能正常工作。看起来这些并不是与事实相比较的。这里的代码

fact(Fact) :- Fact,!. 
fact(Fact):-Fact = ..[Rel, Arg1, Arg2],isa(Arg1, SuperArg). 
SuperFact =..[Rel,SuperArg,Arg2]. 
covers(animal,skin). 
isa(fish,animal). 
isa(bird,animal). 
isa(mammal,animal). 
isa(shark,fish). 
isa(salmon,fish). 
isa(parrot,bird). 
isa(penguin,bird). 
speacial_organ(fish,gills). 
travel(fish,swim). 
birth(bird,lay_eggs). 
special_organ(bird,wings). 
travel(bird,fly). 
birth(fish,lay_eggs). 
birth(mammal,not_lay_eggs). 
birth(shark,not_lay_eggs). 
nature(shark,dangerous). 
food(salmon,delicacy). 
colour(parrot,green). 
travel(penguin,walk). 

这是我想找到该程序

•可鹦鹉飞回答这些问题？
•鹦鹉的颜色是什么？
•鹦鹉是否有皮肤？
•鲨鱼危险吗？

Answer 1

第一步：定义自反transitive-closure的isa/2（以下命名为is_a/2）。

 
isa(fish,animal). 
isa(bird,animal). 
isa(mammal,animal). 
isa(shark,fish). 
isa(salmon,fish). 
isa(parrot,bird). 
isa(penguin,bird). 

is_a(X, Y) :- 
    closure0 (isa, X, Y). 

第二步：指定剩余事实（按谓词指示器分组）。

 
covers(animal,skin). 

special_organ(fish,gills). 
special_organ(bird,wings). 

travel(fish,swim). 
travel(bird,fly). 
travel(penguin,walk). 

birth(bird,lay_eggs). 
birth(fish,lay_eggs). 
birth(mammal,not_lay_eggs). 
birth(shark,not_lay_eggs). 

nature(shark,dangerous). 

food(salmon,delicacy). 

colour(parrot,green). 

第三步：让我们问一些疑问！

• Can parrots fly?

   
  ?- is_a(parrot, X), travel(X, fly). 
      X = bird 
  ; false. 
  

• What is the color of parrots?

   
  ?- is_a(parrot, X), colour(X, Colour). 
      Colour = green, X = parrot   
  ; false. 
  

• Do parrots have skin?

   
  ?- is_a(parrot, X), covers(X, skin). 
      X = animal 
  ; false. 
  

• Are sharks dangerous?

   
  ?- is_a(shark, X), nature(X, dangerous). 
      X = shark 
  ; false.