% Picky eater shellOAVbc rules.
%
% This is the simple version:
%
%   Data about food and animals kept in static objects, new foods and animals
%   cannot be added by the user.
%
%   Names are used as object identifiers. (It's better to store a name in an
%   attribute.)
%
% A better version is in file roPE2.pro.
%
% To start issue goal start: (I thought of this before Microsoft. :-) )
%
% ?- start.

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

% Rule to determine if food F is acceptable. 
%
rule1:if 				
   F:.name=N 				% Get name of food.
  and 
   N:.whenAlive=Animal 			% Find animal used.
  and 
   L=Animal:.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(food,person) 			% Get list of foods and.
  and 					% (Below) test each for acceptability.
   forSome(Food:.isa=food,true,Food:.wouldEat)
 then 
  eatSomething.				% The proposition.

% 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 			% Retreive "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(food,firstQuest,"Is there a menu item?",init).
data(food,moreQuest,"Are there any other menu items?",init).

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

% Single instance objects.
%
data(steak,whenAlive,cow,init).
data(escargot,whenAlive,snail,init).
data(chicken,whenAlive,chicken,init).
data(cow,numLegs,4,init).
data(snake,numLegs,0,init).
data(snail,numLegs,1,init).
data(chicken,numLegs,2,init).

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