Updated: bison-2.1-1

Christopher Faylor cgf-no-personal-reply-please@cygwin.com
Wed Feb 22 05:34:00 GMT 2006

I've made a new version of 'bison' available for download.  This updates
the package to the latest version available from ftp.gnu.org.  I've included
the relevant portions of the Bison NEWS file at the end of this message.

For a brief description of this package, see http://cygwin.com/packages/ .

To update your installation, click on the "Install Cygwin now" link on
the http://cygwin.com/ web page.  This downloads setup.exe to your
system.  Run setup.exe to install or update the bison package.

If you have questions or comments, please send them to the Cygwin
mailing list.  I would appreciate it if you would use the mailing list
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Changes since bison-20030307-1:

Bison News

Changes in version 2.1, 2005-09-16:

* Bison-generated parsers now support the translation of diagnostics like
  "syntax error" into languages other than English.  The default
  language is still English.  For details, please see the new
  Internationalization section of the Bison manual.  Software
  distributors should also see the new PACKAGING file.  Thanks to
  Bruno Haible for this new feature.

* Wording in the Bison-generated parsers has been changed slightly to
  simplify translation.  In particular, the message "memory exhausted"
  has replaced "parser stack overflow", as the old message was not
  always accurate for modern Bison-generated parsers.

* Destructors are now called when the parser aborts, for all symbols left
  behind on the stack.  Also, the start symbol is now destroyed after a
  successful parse.  In both cases, the behavior was formerly inconsistent.

* When generating verbose diagnostics, Bison-generated parsers no longer
  quote the literal strings associated with tokens.  For example, for
  a syntax error associated with '%token NUM "number"' they might
  print 'syntax error, unexpected number' instead of 'syntax error,
  unexpected "number"'.

Changes in version 2.0, 2004-12-25:

* Possibly-incompatible changes

  - Bison-generated parsers no longer default to using the alloca function
    (when available) to extend the parser stack, due to widespread
    problems in unchecked stack-overflow detection.  You can "#define
    YYSTACK_USE_ALLOCA 1" to require the use of alloca, but please read
    the manual to determine safe values for YYMAXDEPTH in that case.

  - Error token location.
    During error recovery, the location of the syntax error is updated
    to cover the whole sequence covered by the error token: it includes
    the shifted symbols thrown away during the first part of the error
    recovery, and the lookahead rejected during the second part.

  - Semicolon changes:
    . Stray semicolons are no longer allowed at the start of a grammar.
    . Semicolons are now required after in-grammar declarations.

  - Unescaped newlines are no longer allowed in character constants or
    string literals.  They were never portable, and GCC 3.4.0 has
    dropped support for them.  Better diagnostics are now generated if
    forget a closing quote.

  - NUL bytes are no longer allowed in Bison string literals, unfortunately.

* New features

  - GLR grammars now support locations.

  - New directive: %initial-action.
    This directive allows the user to run arbitrary code (including
    initializing @$) from yyparse before parsing starts.

  - A new directive "%expect-rr N" specifies the expected number of
    reduce/reduce conflicts in GLR parsers.

  - %token numbers can now be hexadecimal integers, e.g., `%token FOO 0x12d'.
    This is a GNU extension.

  - The option `--report=lookahead' was changed to `--report=look-ahead'.
    The old spelling still works, but is not documented and will be

  - Experimental %destructor support has been added to lalr1.cc.

  - New configure option --disable-yacc, to disable installation of the
    yacc command and -ly library introduced in 1.875 for POSIX conformance.

* Bug fixes

  - For now, %expect-count violations are now just warnings, not errors.
    This is for compatibility with Bison 1.75 and earlier (when there are
    reduce/reduce conflicts) and with Bison 1.30 and earlier (when there
    are too many or too few shift/reduce conflicts).  However, in future
    versions of Bison we plan to improve the %expect machinery so that
    these violations will become errors again.

  - Within Bison itself, numbers (e.g., goto numbers) are no longer
    arbitrarily limited to 16-bit counts.

  - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.

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