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Re: bison-2.4 breaks gcc-4.3.2 build


From: Akim Demaille
Subject: Re: bison-2.4 breaks gcc-4.3.2 build
Date: Tue, 4 Nov 2008 21:08:13 +0100


Le 4 nov. 08 à 20:47, Joel E. Denny a écrit :

On Mon, 3 Nov 2008, Sergei Steshenko wrote:

And bison-2.3a does _not_ break the build, i.e. the
'treelang' broken by
bison-2.4, bison-2.3b is not broken by bison-2.3a, but the

Either you did something wrong or something else strange is happening.
2.3a has the same bug as 2.3b and 2.4:

 % echo '%% start: {asdf} ;' > tmp.y
 % ~/installs/bison/2.3/bin/bison tmp.y && grep asdf tmp.tab.c
     {asdf;}
 % ~/installs/bison/2.3a/bin/bison tmp.y && grep asdf tmp.tab.c
     {asdf}
 % ~/installs/bison/2.3b/bin/bison tmp.y && grep asdf tmp.tab.c
     {asdf}
 % ~/installs/bison/2.4/bin/bison tmp.y && grep asdf tmp.tab.c
     {asdf}

As far as I can tell (and according to Bison's source comments), this
strange little feature is undocumented, and I don't know why the gcc
maintainers would depend on it. It's not that hard to type a semicolon. In general, I don't understand why people like to make life complicated by being so uselessly clever. I guess this feature was originally introduced
for compatibility with some other implementation of Yacc.

Anyway, I pushed the following to branch-2.4.1 to fix it. I'll push to
master soon.

The problem with this fix is that it is very "C/C++/Java" based. That is why is was obsoleted and I believed that Paul had agreed to get rid of it. I'm obviously wrong.

The day we add support for languages that are not using ; as these languages do, we'll have problems. If possible, I'd like to add a warning so that code that lacks this ';' is reported (I don't know yet how feasible this warning is).





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