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Re: Reductions during Bison error handling
From: |
Akim Demaille |
Subject: |
Re: Reductions during Bison error handling |
Date: |
20 May 2002 10:00:56 +0200 |
User-agent: |
Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.4 (Common Lisp) |
Hi Paul,
Thanks a lot for raising this point. Sorry I couldn't be more
responsive, but I was buried under work.
I wholeheartedly subscribe to your suggestion: fixing the error
handling so that it matches the documentation. There is a side issue
though: POSIX. I don't know the details of what POSIX requires, and
actually, maybe it is underspecifying wrt this point. Paul (the
Eggert one) will probably be able to help here. BTW, Paul, (the E
one), you will certainly be very interested by this thread, which is
about the erroneous implementation of error recovery in Bison.
One note: byacc exhibits a behavior which is even worse. Using the
three samples that Paul H. sent, one can observe that byacc rates 0/3
where Bison has 1/3 :) I don't know about Sun YACC, but Paul E. will
find below a shell script which should be easy to use to exercise
Sun's Yacc.
src/bison/grammars % ./errors.sh
== error-1.bison
parse error, unexpected 'x', expecting ';'
== error-2.bison
parse error, unexpected 'x', expecting ';'
* error action *
== error-3.bison
parse error, unexpected 'x', expecting 'z'
r 'x' ';'
== error-1.byacc
syntax error
== error-2.byacc
syntax error
== error-3.byacc
syntax error
I couldn't find Byacc's error reports address, but we should point
them to this discussion too.
Paul H., please, feel free to adjust bison.simple, but please, also
fix bison.c++.
errors.sh
Description: Text Data
Re: Reductions during Bison error handling, Paul Hilfinger, 2002/05/10
Re: Reductions during Bison error handling, Paul Hilfinger, 2002/05/10
Re: Reductions during Bison error handling,
Akim Demaille <=
- Re: Reductions during Bison error handling, Richard Stallman, 2002/05/20
- Re: Reductions during Bison error handling, Paul Hilfinger, 2002/05/20
- Re: Reductions during Bison error handling, Richard Stallman, 2002/05/21
- Re: Reductions during Bison error handling, Hans Aberg, 2002/05/21
- Re: Reductions during Bison error handling, Richard Stallman, 2002/05/23
- Re: Reductions during Bison error handling, Akim Demaille, 2002/05/24
- Re: Reductions during Bison error handling, Hans Aberg, 2002/05/24
Re: Reductions during Bison error handling, Paul Eggert, 2002/05/21
Re: Reductions during Bison error handling, Paul Hilfinger, 2002/05/21
Re: Reductions during Bison error handling, Paul Eggert, 2002/05/22