* Short term
+** Graphviz display code thoughts
+The code for the --graph option is over two files: print_graph, and
+graphviz. This is because Bison used to also produce VCG graphs, but since
+this is no longer true, maybe we could consider these files for fusion.
+
+An other consideration worth noting is that print_graph.c (correct me if I
+am wrong) should contain generic functions, whereas graphviz.c and other
+potential files should contain just the specific code for that output
+format. It will probably prove difficult to tell if the implementation is
+actually generic whilst only having support for a single format, but it
+would be nice to keep stuff a bit tidier: right now, the construction of the
+bitset used to show reductions is in the graphviz-specific code, and on the
+opposite side we have some use of \l, which is graphviz-specific, in what
+should be generic code.
+
+Little effort seems to have been given to factoring these files and their
+rint{,-xml} counterpart. We would very much like to re-use the pretty format
+of states from .output for the graphs, etc.
+
+Also, the underscore in print_graph.[ch] isn't very fitting considering the
+dashes in the other filenames.
+
+Since graphviz dies on medium-to-big grammars, maybe consider an other tool?
+
+** push-parser
+Check it too when checking the different kinds of parsers. And be
+sure to check that the initial-action is performed once per parsing.
+
** m4 names
b4_shared_declarations is no longer what it is. Make it
b4_parser_declaration for instance.
-** glr.cc: %defines
-it should not be mandatory.
+** yychar in lalr1.cc
+There is a large difference bw maint and master on the handling of
+yychar (which was removed in lalr1.cc). See what needs to be
+back-ported.
+
-** $ and others in epilogue
-A stray $ is a warning in the actions, but an error in the epilogue.
-IMHO, it should not even be a warning in the epilogue.
+ /* User semantic actions sometimes alter yychar, and that requires
+ that yytoken be updated with the new translation. We take the
+ approach of translating immediately before every use of yytoken.
+ One alternative is translating here after every semantic action,
+ but that translation would be missed if the semantic action
+ invokes YYABORT, YYACCEPT, or YYERROR immediately after altering
+ yychar. In the case of YYABORT or YYACCEPT, an incorrect
+ destructor might then be invoked immediately. In the case of
+ YYERROR, subsequent parser actions might lead to an incorrect
+ destructor call or verbose syntax error message before the
+ lookahead is translated. */
+
+ /* Make sure we have latest lookahead translation. See comments at
+ user semantic actions for why this is necessary. */
+ yytoken = yytranslate_ (yychar);
-** obstack_copy etc.
-There seems to be some other interesting functions for obstacks that
-we should consider using.
** stack.hh
Get rid of it. The original idea is nice, but actually it makes
the code harder to follow, and uselessly different from the other
skeletons.
-** Variable names.
-What should we name `variant' and `lex_symbol'?
-
** Get rid of fake #lines [Bison: ...]
Possibly as simple as checking whether the column number is nonnegative.
** Rename LR0.cc
as lr0.cc, why upper case?
-** bench several bisons.
-Enhance bench.pl with %b to run different bisons.
-
* Various
** YYERRCODE
Defined to 256, but not used, not documented. Probably the token
This shows that it would be interesting to manage to install skeleton
coverage analysis to the test suite.
-** Table definitions
-It should be very easy to factor the definition of the various tables,
-including the separation bw declaration and definition. See for
-instance b4_table_define in lalr1.cc. This way, we could even factor
-C vs. C++ definitions.
-
* From lalr1.cc to yacc.c
** Single stack
Merging the three stacks in lalr1.cc simplified the code, prompted for
keep $default? See the following point.
** Disabled Reductions
-See `tests/conflicts.at (Defaulted Conflicted Reduction)', and decide
+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
+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?
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
+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
+'Parsing Techniques: a Practical Guide', it includes information about
this issue. Does anybody have it?
tokens, either via escapes (e.g., "x\0y") or via a NUL byte in
the source code. This should get fixed.
-* --graph
-Show reductions.
-
* Broken options ?
** %token-table
** Skeleton strategy
-----
-Copyright (C) 2001-2004, 2006, 2008-2012 Free Software Foundation, Inc.
+Copyright (C) 2001-2004, 2006, 2008-2015 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
projects / bison.git / blobdiff