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Re: GCC-3.2.2 bootstrap FAILURE: 1 reduce/reduce conflict inobjc-parse.y
- From: "Joseph S. Myers" <jsm28 at cam dot ac dot uk>
- To: Ziemowit Laski <zlaski at apple dot com>
- Cc: Gabriel Dos_Reis <gdosreis at sophia dot inria dot fr>, <gcc-bugs at gcc dot gnu dot org>, <gcc at gcc dot gnu dot org>
- Date: Tue, 28 Jan 2003 23:08:03 +0000 (GMT)
- Subject: Re: GCC-3.2.2 bootstrap FAILURE: 1 reduce/reduce conflict inobjc-parse.y
On Tue, 28 Jan 2003, Ziemowit Laski wrote:
> 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.
It is, at very least, very bad grammar style, as discussed in the Bison
manual. The grammar should be changed (even though this may make it more
complicated) to avoid the conflict.
(The number of shift/reduce conflicts not involving error recovery should
also be minimised, with each one individually analysed and justified to
show it does parse correctly. %expect is not meant to be used to shut up
Bison by putting in the number of conflicts it says there are until it's
been verified that those conflicts are correct.)
--
Joseph S. Myers
jsm28@cam.ac.uk