Re: YYSTYPE needs to be defined and moved

[Akim Demaille]

Hi!

Le 21 nov. 2013 à 15:01, Arthur Schwarz <address@hidden> a écrit :

> Most particularly, if the flex option %option bison-bridge is used and 
> YY_DECL is not defined, then the following code is generated (using %option 
> prefix="Slip"):
> extern int Sliplex \
>                (YYSTYPE * yylval_param );

I know nothing about Flex's bison-bridge, I have to idea if it
works properly.

> which makes Sliplex available to yyparse but requires direct visibility to 
> YYSTYPE.
> 
> My though is that the actual code generated by bison should be in the 
> file/global scope of y.tab.hpp and not located in a class and that YYSTYPE 
> should always be generated. As seen in the example below, it is not always 
> generated.
> 
> In y.tab.hpp the definition of YYSTYPE is placed in the class parser as 
> follows:
> 
> In the parser input file Slip.y the following appears:
> 
> 
>  %file-prefix "Slip.bison"
>  %language "C++"
>  %name-prefix "Slip"
>  %output "Slip.Bison.cpp"
> 
>  %union {
>    int   everything;
>  }
> 
> 
> Which causes the generation of (without #lines) is:
> 
> 
> namespace Slip {
> 
>   /// A Bison parser.
>   class parser
>   {
>   public:
>     /// Symbol semantic values.
> #ifndef YYSTYPE
>     union semantic_type
>     {
> 
>    int   everything;
>     };
> #else
>     typedef YYSTYPE semantic_type;
> #endif 

If you want to export your types, then you really need to generate
the header (see -d in the Bison documentation), and include this header
from that scanner.