X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c19988b766d542b4d4c83b1b27579ee83cb5f930..603f1cfdc56691b331b6ef337a8c3633e7a125b3:/TODO?ds=sidebyside diff --git a/TODO b/TODO index ef4a61fc..a3005240 100644 --- a/TODO +++ b/TODO @@ -12,44 +12,13 @@ They should not: it is not documented. But if they need to, let's find something clean (not like YYLSP_NEEDED...). -* readpipe - -It should be replaced to avoid tmp files and to improve portability. -Also, as it is it does not call error () when execve fails, and -therefore, running M4='m4 --version' bison will silently fail instead -of: - - bison: cannot run m4 --version: No such file or directory - -BTW: I would really like to be able to pass arguments to m4... - - * 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 $n on her -union, doesn't she? +Before releasing, make sure the documentation ("Understanding your +parser") refers to the current `output' format. * GLR & C++ @@ -83,10 +52,39 @@ DeRemer and Penello: they already provide the algorithm. * Extensions -** yyerror, yysymprint interface +** %destructor +I think we should document it as experimental, and allow its use in +the next releases. But we also need to port it to GLR. What about +lalr1.cc? Well, read what Hans reported, maybe we don't want +%detructor. On the other hand, there is no reason not to provide it: +users can avoid its use. + +** $foo +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... + +** $-1 +We should find a means to provide an access to values deep in the +stack. For instance, instead of + + baz: qux { $$ = $-1 + $0 + $1; } + +we should be able to have: + + foo($foo) bar($bar) baz($bar): qux($qux) { $baz = $foo + $bar + $qux; } + +Or something like this. + +** 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... +locations, and YYPARSE_PARAMS. For the time being, it is almost +recommended to yyprint to steal internal variables... ** Several %unions I think this is a pleasant (but useless currently) feature, but in the @@ -109,6 +107,31 @@ When implementing multiple-%union support, bare the following in mind: char *sval; } +** %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 @@ -151,7 +174,7 @@ There are a couple of proposed outputs: which is based on Bison. -Sébastien Serrurier (serrur_s@epita.fr) is working on this: he is +Sebastien Serrurier (serrur_s@epita.fr) is working on this: he is expected to contact the authors, design the output, and implement it into Bison. @@ -175,21 +198,11 @@ Paul notes: 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 Find the best graph parameters. [] @@ -205,13 +218,12 @@ skeleton muscles. [] ** 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. +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 @@ -325,7 +337,7 @@ the parser with a means to create the (visual) parse tree. ----- -Copyright (C) 2001, 2002 Free Software Foundation, Inc. +Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc. This file is part of GNU Bison.