[antlr-interest] Duplicate nodes on a parse tree?

[Jean Bovet]

This can be part of the backtracking, yes. Are the duplicate nodes  
colored in green or red?

Jean

On Mar 1, 2007, at 10:16 AM, Vadim Tropashko wrote:

> Here is another way to approach the problem. When
> running the antlrworks interpreter, the parse tree
> don't have any duplicates. How does the interpreter
> constructs the tree?
>
>
> --- Vadim Tropashko <vadimtro at yahoo.com> wrote:
>
>> I'm leveraging debugger parse tree generation as
>> described in
>>
> http://www.antlr.org/wiki/pages/viewpage.action?pageId=1760
>>
>> Everything works as advertised, although I'm getting
>> duplicate nodes. For example given the rule:
>>
>> boolean_primary options { backtrack=true; }
>> :         sim_expr
>> |
>>  member_predicate
>> |                          comparison_predicate
>> ;
>>
>> I'm getting the tree branch like this
>>
>> boolean_primary
>>     sim_expr
>>         ....
>>     sim_expr
>>         ....
>>
>> Is the duplicate "sim_expr" branch occurrence due to
>> backtracking?  Then what would be the right way to
>> filter out those ghost nodes?
>>
>>
>>
>>
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