[antlr-interest] ANTLRWorks destroys its AST

[Stephan Opfer]

Hi,

your advice worked like a charm. Thank you!

Does anybody know how I can replace the grammar I uploaded with the new
one? I am talking about the grammar repository on antlr.org

Best Regards,
  Stephan

On 05/12/2012 05:15 AM, John B. Brodie wrote:
> Greetings!
> 
> Summary: your abbreviation rule has 3 paths for recognition.
> You have supplied '->' rules for only 2 of the paths.
> 
> On 05/11/2012 04:20 AM, Stephan Opfer wrote:
>> Dear ANTLR-Interest Group,
>>
>> I have two grammars, which are almost the same and an example input: A &
>> B | C & !A | (D | E) & F
>>
>> The first grammar works quite nice, the other grammar generates NIL as
>> AST. However, next to the last step in debugging both grammars produced
>> exactly the same ParseTree and exactly the same AST.
>>
>> Just after the consumption of <EOF> the other grammar throws the
>> computed AST away.
> 
> because you have not told ANTLR what to do with that tree.
> 
>>
>> Is it just a ANTLRWorks problem or does anybody know, what I am doing
>> wrong. The only difference between the two grammars is the additional
>> abbreviation rule.
>>
> 
> abbreviation :
>     f1=formula
>       ( ( /* EMPTY */ -> $f1 )
>       | ( IMPLY f2=formula -> ^(OR ^(NOT $f1) $f2) )
>       | ( BIIMPLY f2=formula ->
>              ^(AND ^(OR ^(NOT $f1) $f2) ^(OR ^(NOT $f2) $f1)) )
>       );
> 
> 
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