X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/900c5db5379673765a18c6746fd9139a278cc9a9..98ae96438ebb4465c777a7849f1b4ca222e760e3:/TODO diff --git a/TODO b/TODO index 0e3b95d9..a44f64ec 100644 --- a/TODO +++ b/TODO @@ -12,24 +12,22 @@ They should not: it is not documented. But if they need to, let's find something clean (not like YYLSP_NEEDED...). -* URGENT: Documenting C++ output -Write a first documentation for C++ output. - - * Documentation -Before releasing, make sure the documentation refers to the current -`output' format. - +Before releasing, make sure the documentation ("Understanding your +parser") refers to the current `output' format. -* GLR & C++ -Currently, the GLR parser cannot compile with a C++ compiler. +* lalr1.cc +** vector +Move to using vector, drop stack.hh. +** I18n +Catch up with yacc.c. * 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 +what when two reductions are possible on a given look-ahead token, but one is part of $default. Should we make the two reductions explicit, or just keep $default? See the following point. @@ -52,10 +50,47 @@ DeRemer and Penello: they already provide the algorithm. * Extensions -** yyerror, yysymprint interface +** Labeling the symbols +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... + +But instead of using $a etc., we can use regular variables. And +instead of using (), I propose to use `:' (again). Paul suggests +supporting `->' in addition to `:' to separate LHS and RHS. In other +words: + + r:exp -> a:exp '+' b:exp { r = a + b; }; + +That requires an significant improvement of the grammar parser. Using +GLR would be nice. It also requires that Bison know the type of the +symbols (which will be useful for %include anyway). So we have some +time before... + +Note that there remains the problem of locations: `@r'? + + +** $-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 @@ -88,6 +123,20 @@ 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 @@ -131,7 +180,7 @@ 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. @@ -149,27 +198,19 @@ Paul notes: PDP-10 ports :-) but they should probably be documented somewhere. - + More importantly, Bison does not currently allow NUL bytes in + 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 ? -** %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. [] @@ -304,7 +345,7 @@ the parser with a means to create the (visual) parse tree. ----- -Copyright (C) 2001, 2002 Free Software Foundation, Inc. +Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GNU Bison. @@ -320,5 +361,5 @@ 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. +the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +Boston, MA 02110-1301, USA.