X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/c19988b766d542b4d4c83b1b27579ee83cb5f930..7b5cdcbd176bf71ef4a16977d557cb56d1602511:/TODO

diff --git a/TODO b/TODO
index ef4a61fc..76ca7362 100644
--- a/TODO
+++ b/TODO
@@ -12,55 +12,22 @@ 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 $<foo>n on her
-union, doesn't she?
-
+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.
 
@@ -83,31 +50,67 @@ DeRemer and Penello: they already provide the algorithm.
 
 * Extensions
 
-** yyerror, 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...
+** 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:
 
-** 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.
+       exp (res): exp (a) '+' exp (b) { $res = $a + $b; };
 
-When implementing multiple-%union support, bare the following in mind:
+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...
 
-- when --yacc, this must be flagged as an error.  Don't make it fatal
-  though.
+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:
 
-- The #line must now appear *inside* the definition of yystype.
-  Something like
+       r:exp -> a:exp '+' b:exp { r = a + b; };
 
-	{
-	#line 12 "foo.y"
-	  int ival;
-	#line 23 "foo.y"
-	  char *sval;
-	}
+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 { $$ = $<foo>-1 + $<bar>0 + $1; }
+
+we should be able to have:
+
+  foo($foo) bar($bar) baz($bar): qux($qux) { $baz = $foo + $bar + $qux; }
+
+Or something like this.
+
+** %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 +154,7 @@ There are a couple of proposed outputs:
   which is based on Bison.
   <http://www.goice.co.jp/member/mo/hack-progs/bison-java.html>
 
-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.
 
@@ -169,49 +172,28 @@ 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.	[]
+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.	[]
+** %no-parser
+** %token-table
+** Skeleton strategy
+Must we keep %no-parser?  %token-table?
 
 * src/print_graph.c
-Find the best graph parameters.	[]
-
-* doc/bison.texinfo
-** Update
-informations about ERROR_VERBOSE.	[]
-** Add explanations 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.
+Find the best graph parameters.
 
 * 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 <de-boy_c@epita.fr> 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
@@ -325,21 +307,22 @@ 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, 2006 Free Software Foundation,
+Inc.
 
-This file is part of GNU Bison.
+This file is part of Bison, the GNU Compiler Compiler.
 
-GNU Bison is free software; you can redistribute it and/or modify
+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,
+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.
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.