* The distribution terms for all Bison-generated parsers now permit
using the parsers in nonfree programs. Previously, this permission
was granted only for Bison-generated LALR(1) parsers in C.
* %name-prefix changes the namespace name in C++ outputs.
* The C++ parsers export their token_type.
* Bison now allows multiple %union declarations, and concatenates
their contents together.
* New warning: unused values
Right-hand side symbols whose values are not used are reported,
if the symbols have destructors. For instance:
exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
| exp "+" exp
;
will trigger a warning about $$ and $5 in the first rule, and $3 in
the second ($1 is copied to $$ by the default rule). This example
most likely contains three errors, and could be rewritten as:
exp: exp "?" exp ":" exp
{ $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
| exp "+" exp
{ $$ = $1 ? $1 : $3; if ($1) free ($3); }
;
However, if the original actions were really intended, memory leaks
and all, the warnings can be suppressed by letting Bison believe the
values are used, e.g.:
exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
| exp "+" exp { $$ = $1; (void) $3; }
;
If there are mid-rule actions, the warning is issued if no action
uses it. The following triggers no warning: $1 and $3 are used.
exp: exp { push ($1); } '+' exp { push ($3); sum (); };
The warning is intended to help catching lost values and memory leaks.
If a value is ignored, its associated memory typically is not reclaimed.
* %destructor vs. YYABORT, YYACCEPT, and YYERROR.
Destructors are now called when user code invokes YYABORT, YYACCEPT,
and YYERROR, for all objects on the stack, other than objects
corresponding to the right-hand side of the current rule.
* %expect, %expect-rr
Incorrect numbers of expected conflicts are now actual errors,
instead of warnings.
* GLR, YACC parsers.
The %parse-params are available in the destructors (and the
experimental printers) as per the documentation.
* Bison now warns if it finds a stray `$' or `@' in an action.
* %require "VERSION"
This specifies that the grammar file depends on features implemented
in Bison version VERSION or higher.
* lalr1.cc: The token and value types are now class members.
The tokens were defined as free form enums and cpp macros. YYSTYPE
was defined as a free form union. They are now class members:
tokens are enumerations of the `yy::parser::token' struct, and the
semantic values have the `yy::parser::semantic_type' type.
If you do not want or can update to this scheme, the directive
`%define "global_tokens_and_yystype" "1"' triggers the global
definition of tokens and YYSTYPE. This change is suitable both
for previous releases of Bison, and this one.
If you wish to update, then make sure older version of Bison will
fail using `%require "2.2"'.
* DJGPP support added.
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"'.
Differences to the plain GNU version in the packages collection:
* We do not install the shell wrapper "yacc" (it is supplied because
POSIX requires it and we already have a yacc command).
Changes since 1.75:
* Numerous bug fixes and improvements including:
+ Compatibility (with 1.35 and Solaris yacc) changes;
+ Fixes for GCC 3.2.1;
+ Use Yacc style of conflict reports;
+ Fix bug where error locations were not being recorded correctly;
+ Fix bad interaction with flex 2.5.23.
Please see the ChangeLog file supplied with the bison source code
for more details.
Changes since 1.35 (too many to mention here, please see the
ChangeLog in the bison source distribution):
* GNU m4 is now required.
* Various bug fixes.
* intl source removed.
NetBSD pkgsrc changes:
* Change of maintainer thorpej->cjep.
* C Skeleton
Some projects use Bison's C parser with C++ compilers, and define
YYSTYPE as a class. The recent adjustment of C parsers for data
alignment and 64 bit architectures made this impossible.
Because for the time being no real solution for C++ parser
generation exists, kludges were implemented in the parser to
maintain this use. In the future, when Bison has C++ parsers, this
kludge will be disabled.
This kludge also addresses some C++ problems when the stack was
extended.
* File name clashes are detected
$ bison foo.y -d -o foo.x
fatal error: header and parser would be both named `foo.x'
* A missing `;' ending a rule triggers a warning
In accordance with POSIX, and in agreement with other
Yacc implementations, Bison will mandate this semicolon in a near
future. This eases the implementation of a Bison parser of Bison
grammars by making this grammar LALR(1) instead of LR(2). To
facilitate the transition, this release introduces a warning.
* Revert the C++ namespace changes introduced in 1.31, as they caused too
many portability hassles.
* Fix test suite portability problems.
* Fix C++ issues
Groff could not be compiled for the definition of size_t was lacking
under some conditions.
* Catch invalid @n
As is done with $n.
Summary of changes:
- removal of USE_GTEXINFO
- addition of mk/texinfo.mk
- inclusion of this file in package Makefiles requiring it
- `install-info' substituted by `${INSTALL_INFO}' in PLISTs
- tuning of mk/bsd.pkg.mk:
removal of USE_GTEXINFO
INSTALL_INFO added to PLIST_SUBST
`${INSTALL_INFO}' replace `install-info' in target rules
print-PLIST target now generate `${INSTALL_INFO}' instead of `install-info'
- a couple of new patch files added for a handful of packages
- setting of the TEXINFO_OVERRIDE "switch" in packages Makefiles requiring it
- devel/cssc marked requiring texinfo 4.0
- a couple of packages Makefiles were tuned with respect of INFO_FILES and
makeinfo command usage
See -newly added by this commit- section 10.24 of Packages.txt for
further information.
* Fix Yacc output file names
* Portability fixes
* Italian, Dutch, Swedish, Russian translation
* Many Bug Fixes
* Use of alloca in parsers
* When the generated parser lacks debugging code, YYDEBUG is now 0
(as POSIX requires) instead of being undefined.
* User Actions
Bison has always permitted actions such as { $$ = $1 }: it adds the
ending semicolon. Now if in Yacc compatibility mode, the semicolon
is no longer output: one has to write { $$ = $1; }.
* Better C++ compliance
The output parsers try to respect C++ namespaces.
* Reduced Grammars
Fixed bugs when reporting useless nonterminals.
* 64 bit hosts
The parsers work properly on 64 bit hosts.
* Error messages
Some calls to strerror resulted in scrambled or missing error messages.
* The verbose report includes the rule line numbers.
* Rule line numbers are fixed in traces.
* Parse errors
Verbose parse error messages from the parsers are better looking.
* Fixed parser memory leaks.
When the generated parser was using malloc to extend its stacks, the
previous allocations were not freed.
* Fixed verbose output file.
Some newlines were missing.
Some conflicts in state descriptions were missing.
* Fixed conflict report.
Option -v was needed to get the result.
* Fixed incorrect processing of some invalid input.
* Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
* %token MY_EOF 0 is supported.
Before, MY_EOF was silently renumbered as 257.
* doc/refcard.tex is updated.
* %output, %file-prefix, %name-prefix.
* --output
* `--defines' and `--graph' have now an optionnal argument which is the
output file name. `-d' and `-g' do not change, they do not take any
argument.
* Portability fixes.
* The output file does not define const, as this caused problems when used
with common autoconfiguration schemes. If you still use ancient compilers
that lack const, compile with the equivalent of the C compiler option
`-Dconst='. autoconf's AC_C_CONST macro provides one way to do this.
* Added `-g' and `--graph'.
* The input and the output files has automatically a similar extension.
* NLS support updated; should hopefully be less troublesome.
* Added the old Bison reference card.
* Added `--locations' and `%locations'.
* Added `-S' and `--skeleton'.
* `%raw', `-r', `--raw' is disabled.
* Special characters are escaped when output. This solves the problems
of the #line lines with path names including backslashes.
* New directives.
* @$ Automatic location tracking.
