// behaviors of CSP class and helpers
CSP {
   traversal toAll (UniversalVisitor) { to *; }
   
   // deep copy the CSP
   public CSP copy() {{
      CopyVisitor cv = new CopyVisitor(CSP.class);
      toAll(cv);
      return (CSP)cv.get_return_val();
   }}
   
   // get a set of all variables in the CSP
   Set vars() to Variable {
      init (@ return_val = new HashSet(); @)
      before Variable (@ return_val.add(host); @)
   }

   // get a reduced copy of the CSP, simplified with
   // assignment a
   CSP reduce(Assignment a) to Constraint {
      before CSP (@
        return_val = host.copy();
        return_val.set_constraints(Constraint_List.parse(""));
      @)

      before Constraint (@
         return_val.addConstraint(host.reduce(a));
      @)
   }

   // add a constraint to the CSP
   void addConstraint(Constraint c) {{
      constraints.push(c);
   }}

	double unsat(Assignment a) {{
		return ((double)unsatCount(a)) / constraintCount();
	}}

   int constraintCount() to Constraint {
		init (@ return_val = 0; @)
		before Constraint (@ return_val++; @)
	}

	int unsatCount(Assignment a) to Constraint {
		init (@ return_val = 0; @)
		before Constraint (@
		   // LoD violation:
		   if (host.reduce(a).get_relation().get_relationNumber() == 0)
				return_val++;
		@)
	}
}