Re: C2026 error in VC++ with large number of tokens

Hi Vince,

> Le 22 août 2021 à 22:14, Vince Huffaker <[email protected]> a écrit :
> 
> That macro doesn't seem to exist, but the _MSC_VER does, so this line:
> 
>         #ifndef _MSC_VER
> 
> fixes the issue.  

Yes, of course, sorry about that...

>> Also, do you really need to specify the numbers for all the tokens?  It is because you gave these numbers that the assertion is long.  If bison had numbered itself, there wouldn't be holes, and the assertions is short.  Why do you provide the token numbers?
> We use the Bison parser for reading our native file format.  So, we need to make sure that the token values never change, otherwise we would not be able to read legacy files.  Therefore, we specifically define the values for each token.  Each new version of each object type has its own token value, so the numbers keep going up.  

Makes perfect sense.

> But, maybe there's some alternative approach for bison in the future?  Maybe we could reserve a range of token values... or somehow indicate to Bison that our token values are not truly 'custom', but are sequential numbers... maybe that would help?  Don't know -- just trying ideas..

Your numbers are not consecutive, there are gaps.  Hence the number of clauses: one per (contiguous) range.

> Is there something I can add to the Bison distribution to automatically add that #ifndef line?  Or do I need to wait for a new version?

I'll wrap a fix for the next release.  Meanwhile, you can just disable parse.assert, and the assertion will no longer be emitted.

Or change your installation of Bison.  In ..../data/skeleton/variant.hh, look for

      {]b4_parse_assert_if([[
        ]b4_assert[ (]b4_tok_in($@)[);
      ]])[}

That's where you want to add the #if lines.  Something like

      {]b4_parse_assert_if([[
#if !defined _MSC_VER || defined __clang__
        ]b4_assert[ (]b4_tok_in($@)[);
#endif
      ]])[}