* doc/bison.texinfo (Stack Overflow): xref to Recursion.

[bison.git] / TODO

diff --git a/TODO b/TODO
index 11b1d349d9e258b41ebc6abb0afae92b7d637317..e33f3aeed0f77dda5b717af0a03fe14f2dcb3a95 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,38 +1,377 @@
 -*- outline -*-
 
 -*- outline -*-
 

-* src/reader.c
-** Complete parse_skel_decl () with parse_dquoted_param ().    []
-** Check and cleanup for CPP-out code. []
-
-* src/output.c
-** Output sub-skeleton files.  []
-** Cleanup dirty CPP-out code. []
-*** Useful for %no_parser.     []
-**** New skeleton.     []
-** s/definitions/prologue/  s/user_code/epilogue/.     [ok]
-** s/macro/muscle/.    [ok]
-** Synchronize `#line' directive with user file.       []
-
-* src/getargs.c src/lex.c
-** Synchronize percent and command line options.       []
-
-* src/macrotab.[ch]
-** Removing warnings when compiling. (gcc-warnings).   [ok]
-** s/macro/muscle/.    [ok]
-*** Rename files.      [ok]
-*** Rename functions   [ok]
-*** Echo modifications src/Makefile src/output.c src/reader.c
-***                   src/main.c src/macrotab.c.       [ok]
+* 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.
+
+
+* 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
+
+is really weird.  Revisit them all.
+
+
+* 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.
+
+
+* 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 $<foo>n on her
+union, doesn't she?
+
+
+* 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
+part of $default.  Should we make the two reductions explicit, or just
+keep $default?  See the following point.
+
+** Disabled Reductions
+See `tests/conflicts.at (Defaulted Conflicted Reduction)', and decide
+what we want to do.
+
+** Documentation
+Extend with error productions.  The hard part will probably be finding
+the right rule so that a single state does not exhibit too many yet
+undocumented ``features''.  Maybe an empty action ought to be
+presented too.  Shall we try to make a single grammar with all these
+features, or should we have several very small grammars?
+
+** --report=conflict-path
+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.
+
+
+* 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...
+
+** 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.
+
+When implementing multiple-%union support, bare the following in mind:
+
+- when --yacc, this must be flagged as an error.  Don't make it fatal
+  though.
+
+- The #line must now appear *inside* the definition of yystype.
+  Something like
+
+       {
+       #line 12 "foo.y"
+         int ival;
+       #line 23 "foo.y"
+         char *sval;
+       }
+
+* Unit rules
+Maybe we could expand unit rules, i.e., transform
+
+       exp: arith | bool;
+       arith: exp '+' exp;
+       bool: exp '&' exp;
+
+into
+
+       exp: exp '+' exp | exp '&' exp;
+
+when there are no actions.  This can significantly speed up some
+grammars.  I can't find the papers.  In particular the book `LR
+parsing: Theory and Practice' is impossible to find, but according to
+`Parsing Techniques: a Practical Guide', it includes information about
+this issue.  Does anybody have it?
+
+
+
+* Documentation
+
+** History/Bibliography
+Some history of Bison and some bibliography would be most welcome.
+Are there any Texinfo standards for bibliography?
+
+
+
+* Java, Fortran, etc.
+
+
+** Java
+
+There are a couple of proposed outputs:
+
+- BYACC/J
+  which is based on Byacc.
+  <http://troi.lincom-asg.com/~rjamison/byacc/>
+
+- Bison Java
+  which is based on Bison.
+  <http://www.goice.co.jp/member/mo/hack-progs/bison-java.html>
+
+Sébastien Serrurier (serrur_s@epita.fr) is working on this: he is
+expected to contact the authors, design the output, and implement it
+into Bison.
+
+
+* Coding system independence
+Paul notes:
+
+       Currently Bison assumes 8-bit bytes (i.e. that UCHAR_MAX is
+       255).  It also assumes that the 8-bit character encoding is
+       the same for the invocation of 'bison' as it is for the
+       invocation of 'cc', but this is not necessarily true when
+       people run bison on an ASCII host and then use cc on an EBCDIC
+       host.  I don't think these topics are worth our time
+       addressing (unless we find a gung-ho volunteer for EBCDIC or
+       PDP-10 ports :-) but they should probably be documented
+       somewhere.
+
+
+
+* --graph
+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.     []

 
 * src/print_graph.c
 
 * src/print_graph.c

-** Find the best graph parameters.     []
+Find the best graph parameters.        []

 
 * doc/bison.texinfo
 
 * doc/bison.texinfo

-** Echo modifications of prologue and epilogue.        []
-** Add informations about YYERROR_VERBOSE.     []
-** Add explainations about skeleton muscles.   []
-** Add explainations about %skeleton.  []
+** 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.
+
+* BTYacc
+See if we can integrate backtracking in Bison.  Contact the BTYacc
+maintainers.
+
+** Keeping the conflicted actions
+First, analyze the differences between byacc and btyacc (I'm referring
+to the executables).  Find where the conflicts are preserved.
+
+** Compare with the GLR tables
+See how isomorphic the way BTYacc and the way the GLR adjustments in
+Bison are compatible.  *As much as possible* one should try to use the
+same implementation in the Bison executables.  I insist: it should be
+very feasible to use the very same conflict tables.
+
+** Adjust the skeletons
+Import the skeletons for C and C++.
+
+** Improve the skeletons
+Have them support yysymprint, yydestruct and so forth.
+
+
+* Precedence
+
+** Partial order
+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,
+why can't I decide that the precedence of * and / is the same, but the
+latter is nonassoc?
+
+If there is really no profound motivation, we should find a new syntax
+to allow specifying this.
+
+** RR conflicts
+See if we can use precedence between rules to solve RR conflicts.  See
+what POSIX says.
+
+
+* $undefined
+From Hans:
+- If the Bison generated parser experiences an undefined number in the
+character range, that character is written out in diagnostic messages, an
+addition to the $undefined value.
+
+Suggest: Change the name $undefined to undefined; looks better in outputs.
+
+
+* Default Action
+From Hans:
+- For use with my C++ parser, I transported the "switch (yyn)" statement
+that Bison writes to the bison.simple skeleton file. This way, I can remove
+the current default rule $$ = $1 implementation, which causes a double
+assignment to $$ which may not be OK under C++, replacing it with a
+"default:" part within the switch statement.
+
+Note that the default rule $$ = $1, when typed, is perfectly OK under C,
+but in the C++ implementation I made, this rule is different from
+$<type_name>$ = $<type_name>1. I therefore think that one should implement
+a Bison option where every typed default rule is explicitly written out
+(same typed ruled can of course be grouped together).
+
+Note: Robert Anisko handles this.  He knows how to do it.
+
+
+* Warnings
+It would be nice to have warning support.  See how Autoconf handles
+them, it is fairly well described there.  It would be very nice to
+implement this in such a way that other programs could use
+lib/warnings.[ch].
+
+Don't work on this without first announcing you do, as I already have
+thought about it, and know many of the components that can be used to
+implement it.
+
+
+* Pre and post actions.
+From: Florian Krohm <florian@edamail.fishkill.ibm.com>
+Subject: YYACT_EPILOGUE
+To: bug-bison@gnu.org
+X-Sent: 1 week, 4 days, 14 hours, 38 minutes, 11 seconds ago
+
+The other day I had the need for explicitly building the parse tree. I
+used %locations for that and defined YYLLOC_DEFAULT to call a function
+that returns the tree node for the production. Easy. But I also needed
+to assign the S-attribute to the tree node. That cannot be done in
+YYLLOC_DEFAULT, because it is invoked before the action is executed.
+The way I solved this was to define a macro YYACT_EPILOGUE that would
+be invoked after the action. For reasons of symmetry I also added
+YYACT_PROLOGUE. Although I had no use for that I can envision how it
+might come in handy for debugging purposes.
+All is needed is to add
+
+#if YYLSP_NEEDED
+    YYACT_EPILOGUE (yyval, (yyvsp - yylen), yylen, yyloc, (yylsp - yylen));
+#else
+    YYACT_EPILOGUE (yyval, (yyvsp - yylen), yylen);
+#endif
+
+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.
+
+-----
+
+Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+
+This file is part of GNU Bison.
+
+GNU Bison 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.

 
 

-* tests/
-** Repair Bison to success tests.      [ok]
+GNU Bison 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.