Yes, I think that's a valid extension too, if the user doesn't define
the token number for error.
+* 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
tests/testsuite.dir/51 % echo "()" | ./calc
1.2-1.3: parse error, unexpected ')', expecting error or "number" or '-' or '('
+* yyerror, yyprint 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...
+
* 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.
Where the first part defines struct expression, the second uses it to
define YYSTYPE, and the last uses YYSTYPE. Only this order is valid.
+Note that we have the same problem with GCC.
+
* --graph
Show reductions. []
* Parsing grammars
Rewrite the reader in Bison.
+* Problems with aliases
+From: "Baum, Nathan I" <s0009525@chelt.ac.uk>
+Subject: Token Alias Bug
+To: "'bug-bison@gnu.org'" <bug-bison@gnu.org>
+
+I've noticed a bug in bison. Sadly, our eternally wise sysadmins won't let
+us use CVS, so I can't find out if it's been fixed already...
+
+Basically, I made a program (in flex) that went through a .y file looking
+for "..."-tokens, and then outputed a %token
+line for it. For single-character ""-tokens, I reasoned, I could just use
+[%token 'A' "A"]. However, this causes Bison to output a [#define 'A' 65],
+which cppp chokes on, not unreasonably. (And even if cppp didn't choke, I
+obviously wouldn't want (char)'A' to be replaced with (int)65 throughout my
+code.
+
+Bison normally forgoes outputing a #define for a character token. However,
+it always outputs an aliased token -- even if the token is an alias for a
+character token. We don't want that. The problem is in /output.c/, as I
+recall. When it outputs the token definitions, it checks for a character
+token, and then checks for an alias token. If the character token check is
+placed after the alias check, then it works correctly.
+
+Alias tokens seem to be something of a kludge. What about an [%alias "..."]
+command...
+
+ %alias T_IF "IF"
+
+Hmm. I can't help thinking... What about a --generate-lex option that
+creates an .l file for the alias tokens used... (Or an option to make a
+gperf file, etc...)
+
+* Presentation of the report file
+From: "Baum, Nathan I" <s0009525@chelt.ac.uk>
+Subject: Token Alias Bug
+To: "'bug-bison@gnu.org'" <bug-bison@gnu.org>
+
+I've also noticed something, that whilst not *wrong*, is inconvienient: I
+use the verbose mode to help find the causes of unresolved shift/reduce
+conflicts. However, this mode insists on starting the .output file with a
+list of *resolved* conflicts, something I find quite useless. Might it be
+possible to define a -v mode, and a -vv mode -- Where the -vv mode shows
+everything, but the -v mode only tells you what you need for examining
+conflicts? (Or, perhaps, a "*** This state has N conflicts ***" marker above
+each state with conflicts.)
+
+
+* $undefined
+From Hans:
+- If the Bison generated parser experiences an undefined number in the
+character range, that character is written out in diagnostic messages, an
+addition to the $undefined value.
+
+Suggest: Change the name $undefined to undefined; looks better in outputs.
+
+* Default Action
+From Hans:
+- For use with my C++ parser, I transported the "switch (yyn)" statement
+that Bison writes to the bison.simple skeleton file. This way, I can remove
+the current default rule $$ = $1 implementation, which causes a double
+assignment to $$ which may not be OK under C++, replacing it with a
+"default:" part within the switch statement.
+
+Note that the default rule $$ = $1, when typed, is perfectly OK under C,
+but in the C++ implementation I made, this rule is different from
+$<type_name>$ = $<type_name>1. I therefore think that one should implement
+a Bison option where every typed default rule is explicitly written out
+(same typed ruled can of course be grouped together).
+
+* Pre and post actions.
+From: Florian Krohm <florian@edamail.fishkill.ibm.com>
+Subject: YYACT_EPILOGUE
+To: bug-bison@gnu.org
+X-Sent: 1 week, 4 days, 14 hours, 38 minutes, 11 seconds ago
+
+The other day I had the need for explicitly building the parse tree. I
+used %locations for that and defined YYLLOC_DEFAULT to call a function
+that returns the tree node for the production. Easy. But I also needed
+to assign the S-attribute to the tree node. That cannot be done in
+YYLLOC_DEFAULT, because it is invoked before the action is executed.
+The way I solved this was to define a macro YYACT_EPILOGUE that would
+be invoked after the action. For reasons of symmetry I also added
+YYACT_PROLOGUE. Although I had no use for that I can envision how it
+might come in handy for debugging purposes.
+All is needed is to add
+
+#if YYLSP_NEEDED
+ YYACT_EPILOGUE (yyval, (yyvsp - yylen), yylen, yyloc, (yylsp - yylen));
+#else
+ YYACT_EPILOGUE (yyval, (yyvsp - yylen), yylen);
+#endif
+
+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.
+
-----
Copyright (C) 2001, 2002 Free Software Foundation, Inc.
projects / bison.git / blobdiff