Re: Bison patch for POSIX and Yacc compatibility with %union

[Paul Eggert]

Akim Demaille <address@hidden> writes:

> I find this patch to be quite hard to understand.  Why did you chose
> to allow the identifier at the scanner level?  Why not having accepted
> this extension in the grammar instead?

Because Yacc and older Bisons accept an arbitrary sequence of C tokens
(other than '}' and '{') between '%union' and '{'.  I presumed that
one might want something other than a single C token, perhaps if one
is generating a parser in Objective C or C++, languages that I don't
know in every detail.

That is why I installed a conservative change (i.e., do it the way
that Bison used to do it) rather than a small change (i.e., make the
minimal change needed to support that particular grammar).  If we can
get experts in C++ and Objective C to sign off on a smaller change,
though, that would be better.