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Re: Bison 3.6.90 released [beta]

From: Akim Demaille
Subject: Re: Bison 3.6.90 released [beta]
Date: Fri, 10 Jul 2020 07:28:45 +0200

Now superseded by 3.6.91.

> Le 4 juil. 2020 à 14:57, Akim Demaille <akim@lrde.epita.fr> a écrit :
> Hi all,
> I am super excited to announce the forthcoming release of Bison 3.7, whose
> main novelty, contributed by Vincent Imbimbo, is the generation of
> counterexamples for conflicts.  For instance on a grammar featuring the
> infamous "dangling else" problem, "bison -Wcounterexamples" now gives:
> dangling.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
> Shift/reduce conflict on token "else":
>  Example              "if" exp "if" exp exp • "else" exp
>  First derivation     exp ::=[ "if" exp exp ::=[ "if" exp exp • ] "else" exp ]
>  Second derivation    exp ::=[ "if" exp exp ::=[ "if" exp exp • "else" exp ] ]
> which proves that the grammar is ambiguous by exhibiting a test sample with
> two derivations (corresponding to two parse trees).
> When Bison is installed with text styling enabled, the example is actually
> shown twice, with colors demonstrating the ambiguity (see
> https://www.lrde.epita.fr/~akim/private/bison/dangling-else.png).
> Joshua Watt contributed the option `--file-prefix-map OLD=NEW`, to make
> reproducible builds.
> See the NEWS below for more details.
> We *need* feedback on this beta.  Not just on counterexamples, there were
> other changes affecting all the skeletons.
>        *Please* *,* *pretty* *please* *,* *test* *it* *!*
> Feedback on the format of the counterexamples would also be most useful.

Here are the compressed sources:
  https://alpha.gnu.org/gnu/bison/bison-3.6.91.tar.gz   (5.1MB)
  https://alpha.gnu.org/gnu/bison/bison-3.6.91.tar.lz   (3.1MB)
  https://alpha.gnu.org/gnu/bison/bison-3.6.91.tar.xz   (3.1MB)

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