/* 
  Rules for the shellOAVbc expert system shell. These rules determine
  if a potential candidate for elective office may face difficulties
  because of domestic employees.

*/

%
% Properties associated with the domEmployee class. 
%
% The domEmployee class has three attributes for which properties are
% provided: name, nationality, and visa. (Other attributes have no
% properties.)
%
props(domEmployee,name,'What is *''s name',isString).
props(domEmployee,nationality,'What is *''s citizenship?',isString).
props(domEmployee,visa,'What type of visa does * have?',
 isEnum([h for h,j for j,pr for 'Permanent Resident',f for 'Student'
 ,t for 'Tourist',nv for 'No visa'])).


% candAssesment is the root item, it's value is a string describing
% how the candidates domestic employment will effect a political
% campaign.
%
start:-wipe,deduce(candAssesment,X),sOut<<'Assesment is '<<X<<nl.

% The following rule gets basic data about each employee and then
% determines how that effects his/her electability. Other candidate
% qualities important to voters could be added to this rule, for
% example by adding: `getHobbyInfo(candidate) and candHobby=B'.
% The rule would have to combine `A' and `B' to get a composite
% assessment.

ca1:if 
    getEmplInfo(candidate)
    and candHelp=A 
    then candAssesment:=A.

% The following two rules get basic information about a candidate's
% domestic employees. The first rule determines if the candidate had
% any help. If so the second rule is called, this rule creates an
% instance of the class 'domEmployee' for each employee and calls the
% `getBasicEmpInfo' rule to ask the basic questions.
%
getFirst:if     
    askAndCheck('Do * have any domestic employees?',Employer,yesNo,Ans)
    and 
    ( Ans=true and getMoreEmp(Employer) or Ans=false )
    then getEmplInfo(Employer).

getMore:if 
    new(domEmployee,InstName) and getBasicEmpInfo(InstName)
    and
    askAndCheck('Do * have any other domestic employees?',Employer,yesNo,Ans) 
    and ( Ans=true and getMoreEmp(Employer) or Ans=false )
    then getMoreEmp(Employer).


% The rule below gets the basic information for each employee: their
% name and nationality. (The inference engine will ask the user for
% this data, the questions are part of the attribute's properties.
%
empInitRule:if 
    I:.name=_  and I:.nationality=_ 
    then getBasicEmpInfo(I).


% The three rules below determine if domestic employment practices
% will cause trouble, the result is written in item `candHelp'.  These
% rules consider information on all employees, the `legalX' rules,
% further below, consider individuals. The antecedent of the first
% rule is true if all were legally employed, the antecedent of the
% second rule is true if any employee was hired illegaly, the
% antecedent of the third rule is true if there is incomplete
% information but no employee was found to be hired illegally.

asses1:if 
    forAll(E:.isa=domEmployee,E:.nationality=C and not(C=usa),
      E:.immStatus=canWork) 
    then candHelp:=okay.

asses2:if 
    forSome(E:.isa=domEmployee,E:.nationality=C and not(C=usa),
      E:.immStatus=cantWork) 
    then candHelp:=trouble.

asses3:if 
    forSome(E:.isa=domEmployee,E:.nationality=C and not(C=usa),
      E:.immStatus=unknown)
    then candHelp:=maybeTrouble.
    

% Goals to announce.
%
aGoalList([candAssesment,candHelp]).

% The following three rules determine the legality of employing
% individual people.

legal1:if E:.visa=j or E:.visa=pr then E:.immStatus:=canWork.

legal2:if 
    E:.visa=X and ( X=h or X=f or X=nv or X=t ) 
    then E:.immStatus:=cantWork.

legal3:if true then E:.immStatus:=unknown.