public static List <Item> Eval(BoolExpr expr)
{
if (expr.IsLeaf())
{
return(expr.Lit);
}
if (expr.Op == BoolExpr.BOP.OR)
{
return(Eval(expr.Left).Union(Eval(expr.Right)).ToList());
}
if (expr.Op == BoolExpr.BOP.AND)
{
return(Eval(expr.Left).Intersect(Eval(expr.Right)).ToList());
}
throw new ArgumentException();
}
public static BoolExpr CreateOr(BoolExpr left, BoolExpr right)
{
return(new BoolExpr(BOP.OR, left, right));
}
//
// public factory
//
public static BoolExpr CreateAnd(BoolExpr left, BoolExpr right)
{
return(new BoolExpr(BOP.AND, left, right));
}