Re: C99 in Bison

[Joel E. Denny]

Hi Akim.

On Fri, 28 Aug 2009, Akim Demaille wrote:

> My quotation does not make it clear, but yysyntax_error is always defined (and
> used, even for "simple" messages), and always with this signature.  So that
> one is really wrong.

yysyntax_error is disabled if YYERROR_VERBOSE is off:

  % echo '%% start: ;' > tmp.y
  % ./tests/bison tmp.y 
  % gcc -E tmp.tab.c | grep yysyntax_error

That gives no output unless I add %error-verbose to the grammar.

> so I guess we can afford dropping knr in the generated skeletons, without
> polling in the NEWS (but we can inform in the NEWS of 2.4.2 that 2.5 will
> completely drop KnR support in yacc.c, which was accidentally broken anyway
> since Bison 2.1).  After all, old tarballs are still there.

I'd be willing to take that approach anyway.  Like you said, if someone 
needs K&R, old Bisons are lying around:

  % aptitude search -F %p bison | grep -v ++
  bison
  bison-1.35
  bison-doc

Alternatively, we could poll at help-bison and might get an answer faster.

> As for C90 in bison itself, I'm fine with it.

You mean C99, right?

> Yet C++03 would be better ;)

Why don't we discuss that again when at least 2.5 is released?  Some 
cherry picks are already painful.

Then again, I believe C++03 doesn't support all C99 constructs, such as 
variable length arrays.  So, if we're not careful about our C99 usage, we 
might be making more work for whenever we switch to C++03.