X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/0179dd6542bbc73ae660fd7139a9bb19d82831c2..caf23d249cfc6d9a807989cab399cd97496ef45d:/NEWS diff --git a/NEWS b/NEWS index 311237fb..144d865d 100644 --- a/NEWS +++ b/NEWS @@ -1,14 +1,81 @@ Bison News ---------- -Changes in version 1.49a: - -* Revert the C++ namespace changes introduced in 1.31, as they caused too - many portability hassles. - -* Items overflow - Bison no longer dumps core when there are too many items, it just - dies. +Changes in version 1.49b: + +* GLR parsing + The declaration + %glr-parser + causes Bison to produce a Generalized LR (GLR) parser, capable of handling + almost any context-free grammar, ambiguous or not. The new declarations + %dprec and %merge on grammar rules allow parse-time resolution of + ambiguities. Contributed by Paul Hilfinger. + +* Output Directory + When not in Yacc compatibility mode, when the output file was not + specified, runnning `bison foo/bar.y' created `foo/bar.c'. It + now creates `bar.c'. + +* Undefined token + The undefined token was systematically mapped to 2 which prevented + the use of 2 from the user. This is no longer the case. + +* Unknown token numbers + If yylex returned a code out of range, yyparse could die. This is + no longer the case. + +* Error token + According to POSIX, the error token should be numbered as 256. + Bison extends this requirement by making it a preference: *if* the + user specified that one of her tokens is numbered 256, then error + will be mapped onto another number. + +* Error recovery now conforms to documentation and to POSIX + When a Bison-generated parser encounters a syntax error, it now pops + the stack until it finds a state that allows shifting the error + token. Formerly, it popped the stack until it found a state that + allowed some non-error action other than a default reduction on the + error token. The new behavior has long been the documented behavior, + and has long been required by POSIX. For more details, please see + . + +* Traces + Popped tokens and nonterminals are now reported. + +* Large grammars + Large grammars are now supported (large token numbers, large grammar + size (= sum of the LHS and RHS lengths), large LALR tables). + +* Explicit initial rule + Bison used to play hacks with the initial rule, which the user does + not write. It is now explicit, and visible in the reports and + graphs as rule 0. + +* Useless rules + Before, Bison reported the useless rules, but, although not used, + included them in the parsers. They are now actually removed. + +* Useless rules, useless nonterminals + They are now reported, as a warning, with their locations. + +* Incorrect `Token not used' + On a grammar such as + + %token useless useful + %% + exp: '0' %prec useful; + + where a token was used to set the precedence of the last rule, + bison reported both `useful' and `useless' as useless tokens. + +* Revert the C++ namespace changes introduced in 1.31 + as they caused too many portability hassles. + +* Default locations + By an accident of design, the default computation of @$ was + performed after another default computation was performed: @$ = @1. + The latter is now removed: YYLLOC_DEFAULT is fully responsible of + the computation of @$. * Token end-of-file The token end of file may be specified by the user, in which case, @@ -18,6 +85,95 @@ Changes in version 1.49a: %token YYEOF 0 or %token YYEOF 0 "end of file" + +* Semantic parser + This old option, which has been broken for ages, is removed. + +* New translation + Croatian, thanks to Denis Lackovic. + +* Incorrect token definitions + When fed with `%token 'a' "A"', Bison used to output `#define 'a' 65'. + +* Token definitions as enums + Tokens are output both as the traditional #define's, and, provided + the compiler supports ANSI C or is a C++ compiler, as enums. + This helps debuggers producing symbols instead of values. + +* Reports + In addition to --verbose, bison supports --report=THINGS, which + produces additional information: + - itemset + complete the core item sets with their closure + - lookahead + explicitly associate lookaheads to items + - solved + describe shift/reduce conflicts solving. + Bison used to systematically output this information on top of + the report. Solved conflicts are now attached to their states. + +* Type clashes + Previous versions don't complain when there is a type clash on + the default action if the rule has a mid-rule action, such as in: + + %type bar + %% + bar: '0' {} '0'; + + This is fixed. + +Changes in version 1.35, 2002-03-25: + +* 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. + + +Changes in version 1.34, 2002-03-12: + +* File name clashes are detected + $ bison foo.y -d -o foo.x + fatal error: header and parser would both be named `foo.x' + +* A missing `;' at the end of a rule triggers a warning + In accordance with POSIX, and in agreement with other + Yacc implementations, Bison will mandate this semicolon in the 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. + +* DJGPP support added. + +* Fix test suite portability problems. + +Changes in version 1.33, 2002-02-07: + +* 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. + +Changes in version 1.32, 2002-01-23: + +* Fix Yacc output file names + +* Portability fixes + +* Italian, Dutch translations Changes in version 1.31, 2002-01-14: @@ -46,6 +202,7 @@ Changes in version 1.31, 2002-01-14: * Better C++ compliance The output parsers try to respect C++ namespaces. + [This turned out to be a failed experiment, and it was reverted later.] * Reduced Grammars Fixed bugs when reporting useless nonterminals. @@ -103,7 +260,7 @@ Changes in version 1.31, 2002-01-14: * --output New, aliasing `--output-file'. -Changes in version 1.30: +Changes in version 1.30, 2001-10-26: * `--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 @@ -226,3 +383,24 @@ Output file does not redefine const for C++. Local Variables: mode: outline End: + +----- + +Copyright (C) 2001, 2002 Free Software Foundation, Inc. + +This file is part of GNU Autoconf. + +GNU Autoconf is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Autoconf is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with autoconf; see the file COPYING. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA.