private PreFixExpression create()
{
Operator o = (Operator)items.Pop().Token;
NumericExpression f;
NumericExpression s;
if (items.Peek().IsValue)
{
f = new NumericExpression(items.Pop().Value);
}
else
{
f = create();
}
if (items.Peek().IsValue)
{
s = new NumericExpression(items.Pop().Value);
}
else
{
s = create();
}
PreFixExpression p = new PreFixExpression(o, f, s);
return(p);
}
public PreFixExpression(Stack <Item> list)
{
this.items = list;
PreFixExpression temp = create();
this.Operator = temp.Operator;
this.First = temp.First;
this.Second = temp.Second;
}
private PreFixExpression(Operator op, NumericExpression first, NumericExpression second)
{
this.Operator = op;
this.First = first;
this.Second = second;
}