[antlr-interest] Actions and non-LL(*) rules ??

[Terence Parr]

it still won't execute the {{...}}} before the pred is evaluated  
during prediction. it must not eval disambiguating preds after actions  
in any circumstance.
Ter
On May 3, 2010, at 5:33 AM, Marcin Rzeźnicki wrote:

> On Mon, May 3, 2010 at 1:47 AM, Terence Parr <parrt at cs.usfca.edu>  
> wrote:
>>
>> On May 2, 2010, at 4:42 PM, Marcin Rzeźnicki wrote:
>>> ah, thanks a lot - that explains a lot
>>> So, in th example you posted above - with an action in front it is
>>> equivalent to:
>>> a : {action} ID
>>>  | ID
>>> ;
>>> right?
>>
>> yup.
>>
>>> So, care to give me any hint about reorganizing actions in similar
>>> case? Thx a lot
>>
>> move the pred to the left of action. ;) if function of action, move  
>> code into pred.
>> T
>>
>
> Hi again,
> Thanks to your advice I was able to resolve my problems, yet I think
> that ANTLR is buggy in one aspect. If I understand this correctly:
> during evaluation of semantic predicates  actions are not executed, so
> if the action is in front of a predicate, behavior of parser may be
> inconsistent - parsing and backtracking modes might take different
> routes due to action's side effect. But, if actions is marked as '{{'
> which means execute regardless of backtracking then, following the
> reasoning above, it should not hide following predicates because
> anything this action can do wrt. changing parsing state will be
> visible in both 'modes' and behavior of parsing will be consistent.
> But ANTLR still hides predicate, even if action is '{{'.
>
>
>
> -- 
> Greetings
> Marcin Rzeźnicki