private SyntaxTreeNode Term()
{
SyntaxTreeNode t = Factor();
while ((CurToken != null) &&
(CurToken.Type == TokenType.Multi || CurToken.Type == TokenType.Div))
{
SyntaxTreeNode p = new OpSyntaxTreeNode(CurToken);
p.AddChild(t);
t = p;
MatchToken(CurToken.Type);
SyntaxTreeNode fac = Factor();
if (fac == null)
{
throw new ParseException("need exp after token: *, /");
}
t.AddChild(fac);
}
return t;
}
private SyntaxTreeNode SimpExp()
{
SyntaxTreeNode t = Term();
while ((CurToken !=null)
&& (CurToken.Type == TokenType.Add || CurToken.Type == TokenType.Minus))
{
SyntaxTreeNode p = new OpSyntaxTreeNode(CurToken);
p.AddChild(t);
t = p;
MatchToken(CurToken.Type);
t.AddChild(Term());
}
return t;
}