public static OneNode NewNode(ref string st, ref int pos)
{
OneNode res = null;
while (pos < st.Length && st[pos] == ' ')
{
++pos;
}
//MessageBox.Show("In ONENODE, '" + st[pos] + "'");
if (pos < st.Length)
{
if (Char.IsLower(st[pos]))
{
res = new VarNode("");
}
else
if (Char.IsDigit(st[pos]))
{
res = new IntNode(0);
}
else
if (st[pos] == '(')
{
res = new SignNode(Sign.empty);
}
}
if (res != null && !res.LoadNodeFromString(ref st, ref pos))
{
res = null;
}
return(res);
}
public override OneNode Copy()
{
SignNode sign = new SignNode(this.sign);
return(sign);
}
