maria-developers team mailing list archive

[Sergey Petrunia <sergey@xxxxxxxxxxx>]

On Fri, Jun 19, 2015 at 05:23:32PM +0530, Diwas Joshi wrote:
> hii i have been stuck on some shift/reduce conflict since past few days. It
> is giving the error for the code i have added for select query using the
> udf. I think the rule that I defined under table_factor is conflicting with
> the first rule defined under it.
> 

Notes from our IRC dicussion: we don't think the grammar is ambigous. When one
looks at these two rules:

table_factor:
          table_ident opt_use_partition opt_table_alias opt_key_definition
         | ....
         | table_function '(' table_function_args ')' opt_table_alias

one cannot come up with the same piece of SQL that would be parseable through
both rules. The problem seems to be in how the grammar handles bison's
limitations.

Changing "table_function" to "table_ident" and factoring out the rest of these
two rules into table_factor_part2 seems to make the conflicts go away.

We were also wondering if Sergei Golubchik + Blessing Atie already hit this
problem, but were not able to find any mention of it.


BR
 Sergei
-- 
Sergei Petrunia, Software Developer
MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog