[antlr-interest] Proglem about the root of ASTree

[sishen]

Thanks.

In my opinion, This restriction is too strict. :(
it's can't be reuseable.
And i should use multiple label to mark the token..... like  op1:">"^ |  
op2:"<"^ | op3:"=".....



Bryan Ewbank wrote:
> Yes, this is a restriction - the '^' has to be at a token, because
> that way it's guaranteed to be a single tree node. Rewrite it this
> way:
>
>        test : ID ( ">"^ | "<"^ ) expr ;
>
> Hope this helps,
> - Bryan Ewbank
>
> On 9/21/06, sishen <sishen_freecity at 126.com> wrote:
>> I set buildAST = true;
>>
>> I found something doesn't work when i defined a root.
>>
>>
>> for example:
>>
>> test :  ID  op expr
>>
>> op:
>>          ">"
>>     |   "<"
>>     ;
>>
>>
>> i want "op"  to be the root of  expression.
>> but i can't just write  "op^".  it's a  fault.
>>
>> However, when i write op  suffix  the operator ">"/"<".  it's also 
>> unuseful.
>>
>> What should i do?   thx all~
>>
>>
>
>