X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/3c146b5e6fcdf5226c5966c3f8544a995d47427c..6f04ee6c78ba01f9d8e02dbe2baace0c3bd8f4fd:/TODO diff --git a/TODO b/TODO index ad99639d..473246b5 100644 --- a/TODO +++ b/TODO @@ -2,97 +2,31 @@ * Header guards -En rentrant chez moi, je relance un `make' sur un projet que j'ai avancé -ailleurs durant la semaine. Le système que j'utilise ici est un peu plus -à jour que l'autre, et le Bison est probablement plus récent itou. Ici, -c'est la version 1.33. J'obtiens, en montrant un peu plus que nécessaire: - -----------------------------------------------------------------------> -cd ~/fpub/pyrexpp/Pyrexpp/ -LANGUAGE= /usr/bin/make MAKEFLAGS='-k -j2' -/usr/bin/make -C .. install -make[1]: Entre dans le répertoire `/bpi/titan/home/pinard/fpub/pyrexpp' -install -g bpi -m 2775 -d Prépare-titan -chmod g+sw Prépare-titan -touch Prépare-titan/.estampille -/usr/bin/gcc -fPIC -I/usr/include/python2.2 -IPrépare-titan -g -c -o Prépare-titan/ctools.o ctools.c -bison -d -o Prépare-titan/c-parser.c c-parser.y -/usr/bin/gcc -fPIC -I/usr/include/python2.2 -IPrépare-titan -g -c -o Prépare-titan/c-parser.o Prépare-titan/c-parser.c -flex -t c-scanner.l | grep -v '^#line' > Prépare-titan/c-scanner.c -/usr/bin/gcc -fPIC -I/usr/include/python2.2 -IPrépare-titan -g -c -o Prépare-titan/c-scanner.o Prépare-titan/c-scanner.c -In file included from Prépare-titan/c-scanner.c:547: -Prépare-titan/c-parser.h:1: warning: garbage at end of `#ifndef' argument -Prépare-titan/c-parser.h:2: warning: missing white space after `#define BISON_PR' -/usr/bin/gcc -o Prépare-titan/ctools.so Prépare-titan/ctools.o Prépare-titan/c-scanner.o -shared -lm -python setup.py --quiet build -install -g bpi -m 664 Prépare-titan/ctools.so /bpi/titan/local/lib/python2.2/site-packages/Pyrexpp -python setup.py --quiet install -make[1]: Quitte le répertoire `/bpi/titan/home/pinard/fpub/pyrexpp' -[...] -----------------------------------------------------------------------< - -Diagnostics que je n'avais sûrement pas, plus tôt en journée, sur l'autre -système. En allant voir, je trouve: - -----------------------------------------------------------------------> -#ifndef BISON_PRÉPARE_TITAN_C_PARSER_H -# define BISON_PRÉPARE_TITAN_C_PARSER_H - -# ifndef YYSTYPE -# define YYSTYPE int -# endif -# define IDENTIFIER 257 -[...] - -extern YYSTYPE yylval; - -#endif /* not BISON_PRÉPARE_TITAN_C_PARSER_H */ -----------------------------------------------------------------------< - -Le pré-processeur de C n'est pas à l'aise avec les caractères accentués -dans les identificateurs. - -Bon, de mon expérience, il n'a jamais été nécessaire de protéger un fichier -`.h' de Bison ou Yacc contre de multiples inclusions, mais si ça été -fait, je présume qu'il y avait un problème réel et convaincant à régler, -et qu'il ne s'agit pas d'une simple fantaisie: je ne mettrai donc pas -ça en doute. Mais le choix du nom de l'identificateur laisse à désirer, -tu en conviendras :-). Et faut-il vraiment y inclure le répertoire? - - -* URGENT: Documenting C++ output -Write a first documentation for C++ output. +From Franc,ois: should we keep the directory part in the CPP guard? -* Documentation -Before releasing, make sure the documentation refers to the current -`output' format. - - -* Error messages -Some are really funky. For instance - - type clash (`%s' `%s') on default action +* Yacc.c: CPP Macros -is really weird. Revisit them all. +Do some people use YYPURE, YYLSP_NEEDED like we do in the test suite? +They should not: it is not documented. But if they need to, let's +find something clean (not like YYLSP_NEEDED...). -* read_pipe.c -This is not portable to DOS for instance. Implement a more portable -scheme. Sources of inspiration include GNU diff, and Free Recode. +* Installation +* Documentation +Before releasing, make sure the documentation ("Understanding your +parser") refers to the current `output' format. -* value_components_used -Was defined but not used: where was it coming from? It can't be to -check if %union is used, since the user is free to $n on her -union, doesn't she? - +* lalr1.cc +** vector +Move to using vector, drop stack.hh. * Report ** GLR How would Paul like to display the conflicted actions? In particular, -what when two reductions are possible on a given lookahead, but one is +what when two reductions are possible on a given lookahead token, but one is part of $default. Should we make the two reductions explicit, or just keep $default? See the following point. @@ -112,34 +46,73 @@ Provide better assistance for understanding the conflicts by providing a sample text exhibiting the (LALR) ambiguity. See the paper from DeRemer and Penello: they already provide the algorithm. +** Statically check for potential ambiguities in GLR grammars. See + for an approach. + * Extensions -** yyerror, yysymprint interface -It should be improved, in particular when using Bison features such as -locations, and YYPARSE_PARAMS. For the time being, it is recommended -to #define yyerror and yyprint to steal internal variables... +** Labeling the symbols +Have a look at the Lemon parser generator: instead of $1, $2 etc. they +can name the values. This is much more pleasant. For instance: + + exp (res): exp (a) '+' exp (b) { $res = $a + $b; }; + +I love this. I have been bitten too often by the removal of the +symbol, and forgetting to shift all the $n to $n-1. If you are +unlucky, it compiles... + +But instead of using $a etc., we can use regular variables. And +instead of using (), I propose to use `:' (again). Paul suggests +supporting `->' in addition to `:' to separate LHS and RHS. In other +words: + + r:exp -> a:exp '+' b:exp { r = a + b; }; + +That requires an significant improvement of the grammar parser. Using +GLR would be nice. It also requires that Bison know the type of the +symbols (which will be useful for %include anyway). So we have some +time before... + +Note that there remains the problem of locations: `@r'? + -** Several %unions -I think this is a pleasant (but useless currently) feature, but in the -future, I want a means to %include other bits of grammars, and _then_ -it will be important for the various bits to define their needs in -%union. +** $-1 +We should find a means to provide an access to values deep in the +stack. For instance, instead of -When implementing multiple-%union support, bare the following in mind: + baz: qux { $$ = $-1 + $0 + $1; } -- when --yacc, this must be flagged as an error. Don't make it fatal - though. +we should be able to have: -- The #line must now appear *inside* the definition of yystype. - Something like + foo($foo) bar($bar) baz($bar): qux($qux) { $baz = $foo + $bar + $qux; } - { - #line 12 "foo.y" - int ival; - #line 23 "foo.y" - char *sval; - } +Or something like this. + +** %if and the like +It should be possible to have %if/%else/%endif. The implementation is +not clear: should it be lexical or syntactic. Vadim Maslow thinks it +must be in the scanner: we must not parse what is in a switched off +part of %if. Akim Demaille thinks it should be in the parser, so as +to avoid falling into another CPP mistake. + +** -D, --define-muscle NAME=VALUE +To define muscles via cli. Or maybe support directly NAME=VALUE? + +** XML Output +There are couple of available extensions of Bison targeting some XML +output. Some day we should consider including them. One issue is +that they seem to be quite orthogonal to the parsing technique, and +seem to depend mostly on the possibility to have some code triggered +for each reduction. As a matter of fact, such hooks could also be +used to generate the yydebug traces. Some generic scheme probably +exists in there. + +XML output for GNU Bison and gcc + http://www.cs.may.ie/~jpower/Research/bisonXML/ + +XML output for GNU Bison + http://yaxx.sourceforge.net/ * Unit rules Maybe we could expand unit rules, i.e., transform @@ -170,12 +143,6 @@ Are there any Texinfo standards for bibliography? * Java, Fortran, etc. - Add support for languages other than C and C++. Here is a proposed - patch for Java: - - - - * Coding system independence Paul notes: @@ -190,49 +157,27 @@ Paul notes: PDP-10 ports :-) but they should probably be documented somewhere. - + More importantly, Bison does not currently allow NUL bytes in + tokens, either via escapes (e.g., "x\0y") or via a NUL byte in + the source code. This should get fixed. * --graph -Show reductions. [] +Show reductions. * Broken options ? -** %no-lines [ok] -** %no-parser [] -** %pure-parser [] -** %token-table [] -** Options which could use parse_dquoted_param (). -Maybe transferred in lex.c. -*** %skeleton [ok] -*** %output [] -*** %file-prefix [] -*** %name-prefix [] - -** Skeleton strategy. [] -Must we keep %no-parser? - %token-table? -*** New skeletons. [] +** %token-table +** Skeleton strategy +Must we keep %token-table? * src/print_graph.c -Find the best graph parameters. [] - -* doc/bison.texinfo -** Update -informations about ERROR_VERBOSE. [] -** Add explanations about -skeleton muscles. [] -%skeleton. [] - -* testsuite -** tests/pure-parser.at [] -New tests. - -* input synclines -Some users create their foo.y files, and equip them with #line. Bison -should recognize these, and preserve them. +Find the best graph parameters. * BTYacc -See if we can integrate backtracking in Bison. Contact the BTYacc -maintainers. +See if we can integrate backtracking in Bison. Charles-Henri de +Boysson is working on this, and already has some +results. Vadim Maslow, the maintainer of BTYacc was contacted, and we +stay in touch with him. Adjusting the Bison grammar parser will be +needed to support some extra BTYacc features. This is less urgent. ** Keeping the conflicted actions First, analyze the differences between byacc and btyacc (I'm referring @@ -258,9 +203,6 @@ It is unfortunate that there is a total order for precedence. It makes it impossible to have modular precedence information. We should move to partial orders (sounds like series/parallel orders to me). -This will be possible with a Bison parser for the grammar, as it will -make it much easier to extend the grammar. - ** Correlation b/w precedence and associativity Also, I fail to understand why we have to assign the same associativity to operators with the same precedence. For instance, @@ -340,27 +282,24 @@ at the proper place to bison.simple. Ditto for YYACT_PROLOGUE. I was wondering what you think about adding YYACT_PROLOGUE/EPILOGUE to bison. If you're interested, I'll work on a patch. -* Move to Graphviz -Well, VCG seems really dead. Move to Graphviz instead. Also, equip -the parser with a means to create the (visual) parse tree. +* Better graphics +Equip the parser with a means to create the (visual) parse tree. ----- -Copyright (C) 2001, 2002 Free Software Foundation, Inc. +Copyright (C) 2001-2004, 2006, 2008-2011 Free Software Foundation, Inc. -This file is part of GNU Bison. +This file is part of Bison, the GNU Compiler Compiler. -GNU Bison is free software; you can redistribute it and/or modify +This program 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. +the Free Software Foundation, either version 3 of the License, or +(at your option) any later version. -GNU Bison is distributed in the hope that it will be useful, +This program 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 Bison; see the file COPYING. If not, write to -the Free Software Foundation, Inc., 59 Temple Place - Suite 330, -Boston, MA 02111-1307, USA. +along with this program. If not, see .