Re: GCC-3.2.2 bootstrap FAILURE: 1 reduce/reduce conflict in objc-parse.y

[Ziemowit Laski <zlaski at apple dot com>]

On Monday, Jan 27, 2003, at 23:16 US/Pacific, Joseph S. Myers wrote:

> On Mon, 27 Jan 2003, Ziemowit Laski wrote:
>
> > > An objc maintainer needs to review
> > > <http://gcc.gnu.org/ml/gcc-bugs/2003-01/msg00900.html>.
> > I'm not the maintainer, but the patch is wrong.  One cannot replace
> > 'protocolrefs' with 'non_empty_protocolrefs', as they are optional.
> A reduce/reduce conflict is still a bug, even if the fix is more
> complicated.  Removing %expect is only a workaround.
A reduce/reduce conflict is certainly an annoyance, but it is not a bug 
-- bison has a deterministic, POSIX-annointed method for dealing with 
it, which the grammar writer knows and expects.

A slightly better way, IMHO, would be to allow %expect to take an 
optional second argument

  %expect sr_conflicts [, rr_conflicts]

so that the grammar writer could state her intent more clearly.  
However, since this mechanism doesn't exist, whacking the %expect 
altogether is a sensible approach.

--Zem
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Ziemowit Laski                 1 Infinite Loop, MS 301-2K
Mac OS X Compiler Group        Cupertino, CA USA  95014-2083
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