X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/3ae2b51f0851bfd63f73ca4bc263292839d757b1..e776192e4fcb3b34d8a279d7cc1ea153e96ae2e7:/TODO diff --git a/TODO b/TODO index 14bd676f..af8f10fa 100644 --- a/TODO +++ b/TODO @@ -15,17 +15,24 @@ to #define yyerror and yyprint to steal internal variables... * documentation Explain $axiom (and maybe change its name: BTYacc names it `goal', -byacc `$accept', probably based on AT&T Yacc). Complete the glossary -(item, axiom, ?). +byacc `$accept' probably based on AT&T Yacc, Meta `Start'...). +Complete the glossary (item, axiom, ?). -* report documentation +* Error messages +Some are really funky. For instance + + type clash (`%s' `%s') on default action + +is really weird. Revisit them all. + +* Report documentation Extend with error. The hard part will probably be finding the right rule so that a single state does not exhibit to many yet 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? -* documentation +* Documentation Some history of Bison and some bibliography would be most welcome. Are there any Texinfo standards for bibliography? @@ -52,7 +59,8 @@ When implementing multiple-%union support, bare the following in mind: * --report=conflict-path Provide better assistance for understanding the conflicts by providing -a sample text exhibiting the (LALR) ambiguity. +a sample text exhibiting the (LALR) ambiguity. See the paper from +DeRemer and Penello: they already provide the algorithm. * Coding system independence Paul notes: @@ -67,77 +75,6 @@ Paul notes: PDP-10 ports :-) but they should probably be documented somewhere. -* Output directory -Akim: - -| I consider this to be a bug in bison: -| -| /tmp % mkdir src -| /tmp % cp ~/src/bison/tests/calc.y src -| /tmp % mkdir build && cd build -| /tmp/build % bison ../src/calc.y -| /tmp/build % cd .. -| /tmp % ls -l build src -| build: -| total 0 -| -| src: -| total 32 -| -rw-r--r-- 1 akim lrde 27553 oct 2 16:31 calc.tab.c -| -rw-r--r-- 1 akim lrde 3335 oct 2 16:31 calc.y -| -| -| Would it be safe to change this behavior to something more reasonable? -| Do you think some people depend upon this? - -Jim: - -Is it that behavior documented? -If so, then it's probably not reasonable to change it. -I've Cc'd the automake list, because some of automake's -rules use bison through $(YACC) -- though I'll bet they -all use it in yacc-compatible mode. - -Pavel: - -Hello, Jim and others! - -> Is it that behavior documented? -> If so, then it's probably not reasonable to change it. -> I've Cc'd the automake list, because some of automake's -> rules use bison through $(YACC) -- though I'll bet they -> all use it in yacc-compatible mode. - -Yes, Automake currently used bison in Automake-compatible mode, but it -would be fair for Automake to switch to the native mode as long as the -processed files are distributed and "missing" emulates bison. - -In any case, the makefiles should specify the output file explicitly -instead of relying on weird defaults. - -> | src: -> | total 32 -> | -rw-r--r-- 1 akim lrde 27553 oct 2 16:31 calc.tab.c -> | -rw-r--r-- 1 akim lrde 3335 oct 2 16:31 calc.y - -This is not _that_ ugly as it seems - with Automake you want to put -sources where they belong - to the source directory. - -> | This is not _that_ ugly as it seems - with Automake you want to put -> | sources where they belong - to the source directory. -> -> The difference source/build you are referring to is based on Automake -> concepts. They have no sense at all for tools such as bison or gcc -> etc. They have input and output. I do not want them to try to grasp -> source/build. I want them to behave uniformly: output *here*. - -I realize that. - -It's unfortunate that the native mode of Bison behaves in a less uniform -way than the yacc mode. I agree with your point. Bison maintainters may -want to fix it along with the documentation. - - * Unit rules Maybe we could expand unit rules, i.e., transform @@ -150,7 +87,10 @@ into exp: exp '+' exp | exp '&' exp; when there are no actions. This can significantly speed up some -grammars. +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 +this issue. Does anybody have it? * Stupid error messages An example shows it easily: @@ -184,12 +124,6 @@ scheme. Sources of inspiration include GNU diff, and Free Recode. A round of memory leak clean ups would be most welcome. Dmalloc, Checker GCC, Electric Fence, or Valgrind: you chose your tool. -* Memory leaks in the parser -The same applies to the generated parsers. In particular, this is -critical for user data: when aborting a parsing, when handling the -error token etc., we often throw away yylval without giving a chance -of cleaning it up to the user. - * --graph Show reductions. [] @@ -285,9 +219,6 @@ should recognize these, and preserve them. See if we can integrate backtracking in Bison. Contact the BTYacc maintainers. -* Automaton report -Display more clearly the lookaheads for each item. - * RR conflicts See if we can use precedence between rules to solve RR conflicts. See what POSIX says. @@ -300,11 +231,6 @@ move to partial orders. This will be possible with a Bison parser for the grammar, as it will make it much easier to extend the grammar. -* Parsing grammars -Rewrite the reader in Flex/Bison. There will be delicate parts, in -particular, expect the scanner to be hard to write. Many interesting -features cannot be implemented without such a new reader. - * $undefined From Hans: - If the Bison generated parser experiences an undefined number in the @@ -367,6 +293,10 @@ at the proper place to bison.simple. Ditto for YYACT_PROLOGUE. I was wondering what you think about adding YYACT_PROLOGUE/EPILOGUE to bison. If you're interested, I'll work on a patch. +* Move to Graphviz +Well, VCG seems really dead. Move to Graphviz instead. Also, equip +the parser with a means to create the (visual) parse tree. + ----- Copyright (C) 2001, 2002 Free Software Foundation, Inc.