-*- outline -*-
-* src/reader.c
-Complete parse_skel_decl () with parse_dquoted_param (). []
-Check and cleanup for CPP-out code. []
+* URGENT: Documenting C++ output
+Write a first documentation for C++ output.
-* src/output.c
-Remove %%verbose which is useless.
+* Report and 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.
-Cleanup dirty CPP-out code. []
-** Output sub-skeleton files. []
-Useful for %no_parser. []
-*** New skeleton. []
+* Report and Disabled Reductions
+See `tests/conflicts.at (Defaulted Conflicted Reduction)', and decide
+what we want to do.
-* src/macrotab.[ch]
-Removing warnings when compiling. (gcc-warnings). [ok]
+* 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?
+
+* yyerror, yyprint 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...
+
+* documentation
+Explain $axiom (and maybe change its name: BTYacc names it `goal',
+byacc `$accept' probably based on AT&T Yacc, Meta `Start'...).
+Complete the glossary (item, axiom, ?). Should we also rename `$'?
+BYacc uses `$end'. `$eof' is attracting, but after all we may be
+parsing a string, a stream etc.
+
+* Error messages
+Some are really funky. For instance
+
+ type clash (`%s' `%s') on default action
+
+is really weird. Revisit them all.
+
+* Report 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?
+
+* Documentation
+Some history of Bison and some bibliography would be most welcome.
+Are there any Texinfo standards for bibliography?
+
+* 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;
+ }
+
+* --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.
+
+* 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.
+
+* 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?
+
+* Stupid error messages
+An example shows it easily:
+
+src/bison/tests % ./testsuite -k calc,location,error-verbose -l
+GNU Bison 1.49a test suite test groups:
+
+ NUM: FILENAME:LINE TEST-GROUP-NAME
+ KEYWORDS
+
+ 51: calc.at:440 Calculator --locations --yyerror-verbose
+ 52: calc.at:442 Calculator --defines --locations --name-prefix=calc --verbose --yacc --yyerror-verbose
+ 54: calc.at:445 Calculator --debug --defines --locations --name-prefix=calc --verbose --yacc --yyerror-verbose
+src/bison/tests % ./testsuite 51 -d
+## --------------------------- ##
+## GNU Bison 1.49a test suite. ##
+## --------------------------- ##
+ 51: calc.at:440 ok
+## ---------------------------- ##
+## All 1 tests were successful. ##
+## ---------------------------- ##
+src/bison/tests % cd ./testsuite.dir/51
+tests/testsuite.dir/51 % echo "()" | ./calc
+1.2-1.3: parse error, unexpected ')', expecting error or "number" or '-' or '('
+
+* 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.
+
+* Memory leaks in the generator
+A round of memory leak clean ups would be most welcome. Dmalloc,
+Checker GCC, Electric Fence, or Valgrind: you chose your tool.
+
+* --graph
+Show reductions. []
+
+* Broken options ?
+** %no-lines [ok]
+** %no-parser []
+** %pure-parser []
+** %token-table []
+** Options which could use parse_dquoted_param ().
+Maybe transfered 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
Find the best graph parameters. []
* doc/bison.texinfo
-Update informations about ERROR_VERBOSE. []
-Add explainations about skeleton muscles. []
-Add explainations about %skeleton. []
+** Update
+informations about ERROR_VERBOSE. []
+** Add explainations 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.
+
+* RR conflicts
+See if we can use precedence between rules to solve RR conflicts. See
+what POSIX says.
+
+* Precedence
+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.
+
+This will be possible with a Bison parser for the grammar, as it will
+make it much easier to extend the grammar.
+
+* $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.
+
+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.
projects / bison.git / blobdiff