Re: Section 3.1.2 has what appears to be a bug

[slipbits]

Hi Kaz;

I''ll have to think about this some more. The quick take is that only 
%code import is available for use in D and Java. The remaining tags are 
for C/C++. If this is not correct then please correct me (sigh, having a 
dialog with someone who knows what he's talking about is such a humbling 
experience), and the User's Manual.

Here is my table of reason, which I hope is reasonable.

%code tag

        

C/C++

        

D/Java

        

Description

%code

        

•

        


        

Placed after all declarations

%code import

        

•

        

•

        

Placed in an importable class

%code provides

        

•

        


        

Placed after YYSTAB, YYLTYPE declaration

%code requires

        

•

        


        

Placed before YYSTAB, YYLTYPE declaration

%code top

        

•

        


        

Placed after Bison prologue and before %code require


art

On 6/19/2022 9:06 AM, Kaz Kylheku wrote:
> On 2022-06-17 10:26, slipbits wrote:
> > 3.1.2 Prologue Alternatives, pg. 50
> >     “and the new YYLTYPE definition before the Bison-generated YYSTYPE
> >     and YYLTYPE definitions in both the parser implementation file and
> >     the parser header file”.
> >
> >     This position causes, in this case, YYLTYPE to be doubly defined in the 
> > same scope.
> [ elided ]
> > Is this a bug?
> There are ways in which both the header file and the parser source file
> can independently provide a definition such that they don't clash:
>
>    /* paste freely wherever you want, however many times you want */
>    #ifndef FOO_DEFINED
>    struct foo { int x; };
>    #define FOO_DEFINED
>    #endif
>
> The text refers to an example, and in that example this appears:
>
>    #define YYLTYPE YYLTYPE
>    typedef struct YYLTYPE
>    { ...
>
> in all likelihood, the Bison-generated skeleton code is checking for
> the presence of the preprocessor symbol
>
> You should try the example; if that doesn't work, then there is a bug.
>
> I don't use YYLTYPE, but for YYSTYPE, Bison clearly generates
> code like:
>
>    if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
>    typedef union YYSTYPE
>   {
>
> Not sure about Java and other supported languages that don't have
> preprocessing.