X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c28e8b685bf8b335383f32f87e3b2fcf5d5976e5..009285d20ad91837042c92e8b67237224b6361b2:/TODO diff --git a/TODO b/TODO index ea878c9e..7d4a5fb4 100644 --- a/TODO +++ b/TODO @@ -1,31 +1,64 @@ * Short term -** scan-code.l -Avoid variables for format strings, as then GCC cannot check them. -show_sub_messages should call show_sub_message. +** 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. -** obstack_copy etc. -There seems to be some other interesting functions for obstacks that -we should consider using. + /* 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); + ** 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. @@ -52,9 +85,6 @@ since it is no longer bound to a particular parser, it's just a ** 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 @@ -118,12 +148,6 @@ really possible? The test suite does not exercise this case. 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 @@ -152,13 +176,13 @@ 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 +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? @@ -219,9 +243,9 @@ 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 +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? @@ -249,9 +273,6 @@ Paul notes: 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 @@ -348,7 +369,7 @@ End: ----- -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.