[antlr-interest] Deciphering the TreeWalker error message ...
srinivasan karthikeyan pitchai
srinivasan.karthikeyan.pitchai at oracle.com
Wed Jul 20 23:03:28 PDT 2011
Hey Grey,
Yes you are absolutely right, the first element is a rule reference.
My sclarSubExpression snippet is as follows:-
sclarSubExpression
:
^(SUB_EXPR ^(sign sse=sclarSubExpression))
| ^(SUB_EXPR expressionWithParen)
| ^(SUB_EXPR function)
| ^(SUB_EXPR object_name)
| ^(SUB_EXPR constant)
| ^(SUB_EXPR coalesce_exp)
| ^(SUB_EXPR nullif_exp)
| ^(SUB_EXPR case_expression)
;
expressionWithParen
:
^(PAREN_SCLAR_EXPRESSION sclarExpression+)
;
The toStringTree AST is also provided below:
Works:-
----------
DML_STATEMENT DOWN select DOWN SELECT_LIST DOWN SELECT_ITEM DOWN
COMPOUND_EXPR DOWN SUB_EXPR DOWN PAREN_SCLAR_EXPRESSION DOWN
COMPOUND_EXPR DOWN SUB_EXPR DOWN 1 UP UP UP UP UP UP UP from DOWN
TABLE_LIST_ITEM DOWN TABLE_OR_VIEW_NAME DOWN table1 UP UP UP where DOWN
CONDITION_LIST DOWN between DOWN COMPOUND_EXPR DOWN SUB_EXPR DOWN 2 UP
UP and DOWN COMPOUND_EXPR DOWN SUB_EXPR DOWN 3 UP UP COMPOUND_EXPR DOWN
SUB_EXPR DOWN 4 UP UP UP UP UP UP UP UP
Parser AST Tree : (DML_STATEMENT (select (SELECT_LIST (SELECT_ITEM
(COMPOUND_EXPR (SUB_EXPR (PAREN_SCLAR_EXPRESSION (COMPOUND_EXPR
(SUB_EXPR 1))))))) (from (TABLE_LIST_ITEM (TABLE_OR_VIEW_NAME table1)))
(where (CONDITION_LIST (between (COMPOUND_EXPR (SUB_EXPR 2)) (and
(COMPOUND_EXPR (SUB_EXPR 3)) (COMPOUND_EXPR (SUB_EXPR 4))))))))
Fails:
-------
DML_STATEMENT DOWN select DOWN SELECT_LIST DOWN SELECT_ITEM DOWN
COMPOUND_EXPR DOWN SUB_EXPR DOWN PAREN_SCLAR_EXPRESSION DOWN
COMPOUND_EXPR DOWN SUB_EXPR DOWN 1 UP UP UP UP UP UP UP from DOWN
TABLE_LIST_ITEM DOWN TABLE_OR_VIEW_NAME DOWN table1 UP UP UP where DOWN
CONDITION_LIST DOWN between DOWN COMPOUND_EXPR DOWN SUB_EXPR DOWN 2 UP
UP and DOWN COMPOUND_EXPR DOWN SUB_EXPR DOWN 3 UP UP COMPOUND_EXPR DOWN
SUB_EXPR DOWN 4 UP UP UP UP UP UP UP UP
Parser AST Tree : (DML_STATEMENT (select (SELECT_LIST (SELECT_ITEM
(COMPOUND_EXPR (SUB_EXPR (PAREN_SCLAR_EXPRESSION (COMPOUND_EXPR
(SUB_EXPR 1))))))) (from (TABLE_LIST_ITEM (TABLE_OR_VIEW_NAME table1)))
(where (CONDITION_LIST (between (COMPOUND_EXPR (SUB_EXPR 2)) (and
(COMPOUND_EXPR (SUB_EXPR 3)) (COMPOUND_EXPR (SUB_EXPR 4))))))))
Thanks for spending your valuable time looking into this issue.
Regards,
Vasan
On 7/21/2011 11:23 AM, Gary Miller wrote:
> Hey Vasan,
>
> Without seeing the reset of the tree walker grammar and the toStringTree of
> the AST I'm really just guessing.
>
> The rule looks a bit odd to me.
> All my tree walker rules look more like
>
> compoundExpression
> :
> ^(SOMETOKEN conversion_clause)
> | sclarSubExpression
> ;
>
> I guess you can have rules as the first element of a tree, its just not
> something that turns up in my tree grammars.
>
> Regards
> Gary
>
> On Thu, Jul 21, 2011 at 3:29 PM, srinivasan karthikeyan pitchai<
> srinivasan.karthikeyan.pitchai at oracle.com> wrote:
>
>> Hi Folks,
>> I forgot to mention. The compoundExpression rule has options{backtrack
>> = true;} set that is it reads like
>>
>> compoundExpression
>> options {backtrack = true;}
>> :
>> ^(sclarSubExpression conversion_clause)
>> | sclarSubExpression
>> ;
>>
>> Thanks,
>> Vasan
>>
>>
>>
>> On 7/21/2011 10:56 AM, srinivasan karthikeyan pitchai wrote:
>>> Jim, Gray, Loring,
>>> Thanks for pitching in to give me some direction to focus on.
>>>
>>> ANTLR Gurus,
>>>
>>> I've solved the issue. Still I am unable to reason out my fix.
>>>
>>> I am providing the offending grammar snippet below and would appreciate
>>> your rationale to get an insight into the problem and how the fix works!!
>>>
>>> The below rule fails with the "
>>>
>>> no viable alt; token=[@-1,0:0='DOWN'" error message
>>>
>>> compoundExpression:
>>> ^(sclarSubExpression conversion_clause)
>>> | sclarSubExpression
>>> ;
>>>
>>> However when I change the rule like the following, i.e make the
>>> conversion_clause optional and then remove the second alternative every
>>> thing works fine!! In my mind both the rules are semantically identical.
>>>
>>> compoundExpression:
>>> ^(sclarSubExpression conversion_clause?)
>>> ;
>>>
>>> Thanks a ton.
>>>
>>> -Vasan
>>>
>>> On 7/21/2011 4:16 AM, Jim Idle wrote:
>>>> Or use the dot description producing methods and create a nice graphic
>>>> with graphviz. Much easier to see that way.
>>>>
>>>> Jim
>>>>
>>>>> -----Original Message-----
>>>>> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
>>>>> bounces at antlr.org] On Behalf Of Gary Miller
>>>>> Sent: Wednesday, July 20, 2011 3:44 PM
>>>>> To: antlr-interest at antlr.org
>>>>> Subject: Re: [antlr-interest] Deciphering the TreeWalker error message
>>>>> ...
>>>>>
>>>>> I often find it usefully to print out the AST (toStringTree in Java)
>>>>> and walk through the tree grammar manually.
>>>>>
>>>>> Regards
>>>>> Gary
>>>>>
>>>>> On Thu, Jul 21, 2011 at 3:15 AM, Loring Craymer<lgcraymer at yahoo.com>
>>>>> wrote:
>>>>>
>>>>>> "UP" and "DOWN" tokens (start/end of child list for tree) do not have
>>>>>> location information attached so no line/column error reporting.
>>>>>> Mostly the error says that you started a subtree that your grammar
>>>>>> does not match, probably an LPAREN or RPAREN rooted subtree from your
>>>>>> report of cases where you do or do not get the error.
>>>>>>
>>>>>> --Loring
>>>>>>
>>>>>>
>>>>>>
>>>>>>> ________________________________
>>>>>>> From: srinivasan karthikeyan pitchai<
>>>>>> srinivasan.karthikeyan.pitchai at oracle.com>
>>>>>>> To: antlr-interest at antlr.org
>>>>>>> Cc: Terence Parr<parrt at cs.usfca.edu>
>>>>>>> Sent: Wednesday, July 20, 2011 9:46 AM
>>>>>>> Subject: [antlr-interest] Deciphering the TreeWalker error message
>>>>> ...
>>>>>>> Hi Folks,
>>>>>>> What does the ANTLR walker error message like the following mean?
>>>>>>>
>>>>>>> no viable alt; token=[@-1,0:0='DOWN'
>>>>>>>
>>>>>>>
>>>>>>> Would appreciate any general guidance/suggestions to zero in on the
>>>>>>> errors of this nature.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Vasan
>>>>>>>
>>>>>>>
>>>>>>> Input sql:
>>>>>>> -----------
>>>>>>>
>>>>>>> select (1) from table1
>>>>>>> where 2 between 3 and 4;
>>>>>>>
>>>>>>>
>>>>>>> Error Message:
>>>>>>> --------------------
>>>>>>>
>>>>>>> TDWalker1.g: node from after line 2:8 [start1, startStatement, dml,
>>>>>>> query_term, query_expression, query, query_unit, where_clause,
>>>>>>> condition_list, condition_subexpression, condition] Walker1: no
>>>>>>> viable alt; token=[@-1,0:0='DOWN',<2>,0:-1] (decision=127 state 0)
>>>>>>> decision=<<590:1: condition options {backtrack=true; } : ( ^(
>>>>>>> comparison_operator ( condition_quantifier )? c1= condition c2=
>>>>>>> condition ) | ^( BETWEEN expression ^( and_or_operator c1= condition
>>>>>>> c2= condition ) ) | ^( condition_operator expression c1= condition
>>>>> ^(
>>>>>>> ESCAPE escape_character ) ) | ^( condition_operator expression c1=
>>>>>>> condition )
>>>>>>> | ^( condition_operator expression_list c1= condition ) | ^( NOT c1=
>>>>>>> condition ) | ^( EXISTS expression ) | ^( IS_NOT_NULL expression ) |
>>>>>>> ^( IS_NULL expression ) | ^( IS_NOT expression UNTIL_CHANGED ) | ^(
>>>>>>> IS expression UNTIL_CHANGED ) | ^( IS_NOT expression UNTIL_CLOSED )
>>>>> |
>>>>>>> ^( IS expression UNTIL_CLOSED ) | expression | condition_list );>>
>>>>>> context=......
>>>>>>> However the following SQL, that just doesn't have the parenthesis
>>>>>>> around 1, works fine!!!
>>>>>>>
>>>>>>> select (1) from table1
>>>>>>> where 2 between 3 and 4;
>>>>>>>
>>>>>>>
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