% Picky eater shellOAVbc rules.
%
% This is the better version.
%
% (This code was a solution to EE 4785 1995 HW 5, Problem 2.)
%
% In this version two classes are used: one for
% foods, `foodType', the other for animals, `animal'.
%
% There is one disadvantage over the simple version, which is a
% shortcoming of the shell: in questions presented to the user objects
% are identified by their object name (e.g., foodType3) rather than
% their name (e.g., bakedZiti). This is easy to fix, in fact it was a
% homework question in a previous semester.
%
% (The solution in file roPE.pro does not have a class for food and
% animals.)  Because foods and animals are instances their object
% names will be of the form foodType1, foodType2, animal1, animal2,
% etc. Therefore the predicate Food:.whenAlive=Animal will not
% work. Instead the following would have to be used to find out what
% `Food' was made from:
% thereExist(FO:.name=Food,FO:.whenAlive=Animal).  See rules `nfr' and
% `nar'.
%
% Difference between class `food' and `foodType'.
%
% There will be an instance of `food' for each food the user is
% considering (i.e., on the menu). There will be an instance of
% `foodType' for every food the expert system knows about.

% Picky eater shellOAVbc rules.
%
% To start issue goal:
%
% ?-start.

% Start shell by finding truth value of eatSomething.
%
start:-rootGoal(eatSomething).

% Rule to determine if food F is acceptable. 
%
rule1:if                                
   F:.name=FoodName                     % Get name of menu item.
  and 
   getFoodObjName(FoodName,FoodObj)     % Make food object, if necessary.
  and
   FoodObj:.whenAlive=AnimalName        % Find animal used.
  and
   getAnimalObjName(AnimalName,AnObj)   % Make animal object, if necessary.
  and 
   L=AnObj:.numLegs                     % Find number of legs.
  and 
   call(number(L)) and L>1 and L<5      % Test number.
 then 
  F:.wouldEat.                          % The proposition.

rule2:if 
   doList(menu,person)                  % Get list of people and.
  and                                   % (Below) test each for acceptability.
   forSome(Food:.isa=menu,true,Food:.wouldEat)
 then 
  eatSomething.                         % The proposition.

nfr:if                                  % (Below) succeed if food is
                                        % already in system.
     thereExist(ObjName:.isa=foodType,ObjName:.name=FoodName)
    or                                  % Otherwise...
     new(foodType,ObjName)              % ...create a new instance.
    and                                 % (Below) assign name.
     conclude(ObjName:.name,FoodName,user)
    and
     sOut<<FoodName<<" is new, it will be called "<<ObjName<<nl
    then
     getFoodObjName(FoodName,ObjName).

nar:if                                  % (Below) succeed if animal is
                                        % already in system.
     thereExist(ObjName:.isa=animal,ObjName:.name=AnimalName)
    or                                  % Otherwise ...
     new(animal,ObjName)                % ...create a new instance.
    and                                % (Below) assign name.
     conclude(ObjName:.name,AnimalName,user)   
    and
     sOut<<AnimalName<<" is new, it will be called "<<ObjName<<nl
    then
     getAnimalObjName(AnimalName,ObjName).

% Command which asks about first instance in Class.
%
newInstRule1:if 
   Class:.firstQuest=Q                  % Get first question.
  and 
   askAndCheck(Q,Parent,yesNo,Ans)      % Ask.
  and                                   % (Below) If yes, create instance.
   ( Ans=true and makeNew1(Class,Parent) or Ans=false )
 then 
  doList(Class,Parent).                 % The command.

% Command which creates instance and asks about more instances.
%
newInstRule2:if 
   new(Class,InstName)                  % Create instance.
  and 
   InstName:.name=T                     % Find name.
  and 
   Class:.moreQuest=Q                   % Retrieve "more" question.
  and 
   askAndCheck(Q,Parent,yesNo,Ans)      % Ask.
  and                                   % If yes, make recursive call.
   ( Ans=true and makeNew1(Class,Parent) or Ans=false )
 then 
  makeNew1(Class,Parent).               % The command.
        
% Data and properties for food class.
%
data(menu,firstQuest,"Is there a menu item?",init).
data(menu,moreQuest,"Are there any other menu items?",init).

props(menu,name,
 "This menu item will be refered to as *. What food is it?",isString).

% Properties for foodType and animal classes.

props(foodType,whenAlive,"What animal is * made out of?",isString).

props(animal,numLegs,"How many legs does a * have?",isNum(min(0))).


% Instances of foodType class. (These instances have names that
% end in "U1", "U2", etc.)  Additional instances may be entered by
% rules; these will be named "foodType1", "foodType2", etc.


data(foodTypeU1,isa,foodType,init).
data(foodTypeU1,name,steak,init).
data(foodTypeU1,whenAlive,cow,init).
data(foodTypeU2,isa,foodType,init).
data(foodTypeU2,name,escargot,init).
data(foodTypeU2,whenAlive,snail,init).
data(foodTypeU3,isa,foodType,init).
data(foodTypeU3,name,chicken,init).
data(foodTypeU3,whenAlive,chicken,init).

% Instances of animal class.

data(animalU1,isa,animal,init).
data(animalU1,name,cow,init).
data(animalU1,numLegs,4,init).
data(animalU2,isa,animal,init).
data(animalU2,name,snake,init).
data(animalU2,numLegs,0,init).
data(animalU3,isa,animal,init).
data(animalU3,name,snail,init).
data(animalU3,numLegs,1,init).
data(animalU4,isa,animal,init).
data(animalU4,name,chicken,init).
data(animalU4,numLegs,2,init).
nameList(animal,5).

% Items to announce when proven.
%
aGoalList([menu:.wouldEat,eatSomething]).