Re: endless loop - crashing application

On 08/22/2016 06:46 AM, Larry Evans wrote:
> On 08/22/2016 04:04 AM, Joel de Guzman wrote:
>> On 22/08/2016 1:09 PM, Jens Kallup wrote:
>>> Hello,
>>>
>>> QString, and QMessageBox are library functions from Qt.
>>> QString is the equalivant of std::string.
>>>
>>> I have change the source, so it should be compiled with
>>> STL.
>>> Thanks for helping
>>
>> Before anything else, have you tried BOOST_SPIRIT_DEBUG to
>> see a trace where the infinite recursion happens? I suspect
>> left recursive rules.
>>
>> Regards,
>>
> Hi Joel,
>
> I tried that; however, the problem I encountered was not at
> run-time (which I guess is what BOOST_SPIRIT_DEBUG helps with)
> but at compile_time where, with the code posted by Jens in his
> last email, results in errors about too many template instantiations:
>
> --{--cut here--
> yymain.email2016-08-22_0009.cc:525:32:   required from here
> /home/evansl/prog_dev/boost/releases/ro/boost_1_61_0/boost/core/enable_if.hpp:41:10:
> fatal error: template instantiation depth exceeds maximum of 100 (use
> -ftemplate-depth= to increase the maximum)
>     struct enable_if : public enable_if_c<Cond::value, T> {};
>            ^
> compilation terminated.
> --}-- cut here--
>
> Deciphering why this happening from the *huge* compiler error
> messages is daunting :(

Cutting out some of the rule definitions until there was just factor
avoided in 'excceeds maximum' error message.  IOW:

--{--cut here--
#define CUT_RULES 1
#if CUT_RULES
   #define CUT_EXPRESSION 1
   #if CUT_EXPRESSION
   #else
              expression =
                  factor                            [ _val  = qi::_1 ]
                  >> *(   ('+' >> factor            [ _val += qi::_1 ])
                      |   ('-' >> factor            [ _val -= qi::_1 ])
                      )
                  ;
   #endif //CUT_EXPRESSION
              factor =
                  tok.number_digit                [ _val = qi::_1 ]
                  |   ('-' >> factor              [ _val = neg(qi::_1)])
                  |   ('+' >> factor              [ _val = qi::_1 ] )
                  ;
#else
//as before
#endif //CUT_RULES
--}--cut here--

compiles, but with #define CUT_EXPRESSION 0, compilation fails with
the 'excceeds maximum' error message.

-regards,
Larry






------------------------------------------------------------------------------