Re: Bison + Flex on C++ don't work

[Akim Demaille]

> Le 6 mai 2019 à 02:37, Joao Pedro Abreu De Souza <address@hidden> a écrit :
> 
> Hi folks. My friend Nicholas and I are trying to make a compiler for a
> simpler language(just expressions by now) with flex and bison using C++.

Hi guys,

You departed from the original example by using Flex's C++ output.
It changes many things.

I think that your problem is that you specified, in driver.hh:

> // Give Flex the prototype of yylex we want ...
> #define YY_DECL \
>     yy::parser::symbol_type yylex(driver &drv)
> // ... and declare it for the parser's sake.
> YY_DECL;

which is a bad because you are asking Flex to define the yylex
*function* instead of the yyFlexLexer::yylex *member function*.
As a result, none of the yyFlexLexer member variables will be
found in yylex.

Fix your definition of YY_DECL into something like

> #define YY_DECL \
>     yy::parser::symbol_type yyFlexLexer yylex(driver &drv)




If you really want to use C++ output with Flex, you might find
some inspiration here:

https://gitlab.lrde.epita.fr/vcsn/vcsn/tree/master/lib/vcsn/dot

Cheers.