In the following grammar, the 'exp' nonterminal is trivially useless.
So, of course, its rules are useless too.
%%
input: '0' | exp
exp: exp '+' exp | exp '-' exp | '(' exp ')'
Previously all the useless rules were reported, including those whose
left-hand side is the 'exp' nonterminal:
warning: 1 nonterminal useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
2.14-16: warning: nonterminal useless in grammar: exp [-Wother]
input: '0' | exp
^^^
2.14-16: warning: rule useless in grammar [-Wother]
input: '0' | exp
^^^
! 3.6-16: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
! 3.20-30: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
! 3.34-44: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
The interest of being so verbose is dubious. I suspect most of the
time nonterminals are not expected to be useless, so the user wants to
fix the nonterminal, not remove its rules. And even if the user
wanted to get rid of its rules, the position of these rules probably
does not help more that just having the name of the nonterminal.
This commit discard these messages, marked with '!', and keep the
others. In particular, we still report:
2.14-16: warning: rule useless in grammar [-Wother]
input: '0' | exp
^^^
All the useless rules (including the '!' ones) are still reported in
the reports (xml, text, etc.); only the diagnostics on stderr change.
* src/gram.c (grammar_rules_useless_report): Don't complain about
useless rules whose lhs is useless.
* src/reduce.h, src/reduce.c (reduce_nonterminal_useless_in_grammar):
Take a sym_content as argument.
Adjust callers.
* tests/reduce.at (Useless Rules, Underivable Rules, Reduced Automaton):
Adjust.
* origin/maint:
build: don't try to generate docs when cross-compiling
package: fix a reporter's name
%union: fix the support for named %union
package: bump to 2015
flex: don't trust YY_USER_INIT
yacc.c: fix broken union when api.value.type=union and %defines are used
doc: fix missing xref
gnulib: update
location: remove some ugly debugging code traces
build: use abort to pacify compiler errors
package: bump to 2014
doc: specify documentation encoding
Rather than having duplicate info in the symbol and the alias that has
to be resolved later on, both the symbol and the alias have a common
pointer to a separate structure containing this info.
* src/symtab.h (sym_content): New structure.
* src/symtab.c (sym_content_new, sym_content_free, symbol_free): New
* src/AnnotationList.c, src/conflicts.c, src/gram.c, src/gram.h,
* src/graphviz.c, src/ielr.c, src/output.c, src/parse-gram.y, src/print.c
* src/print-xml.c, src/print_graph.c, src/reader.c, src/reduce.c,
* src/state.h, src/symlist.c, src/symtab.c, src/symtab.h, src/tables.c:
Adjust.
* tests/input.at: Fix expectations (order changes).
* src/gram.c (grammar_rules_useless_report): Let -fcaret handle the
pretty-printing of the guilty rules.
(rule_print): Inline in its only use.
* tests/conflicts.at, tests/existing.at, tests/reduce.at,
* tests/regression.at: Adjust.
* NEWS: Document.
* src/gram.c (print_lhs): Use %*s to indent.
* src/print_graph.c (print_lhs): Use obstack_printf.
Became simple enough to be inlined in...
(print_core): here.
Use a "rule*" instead of an index in "rules[]".
* origin/maint:
misc: pacify the Tiny C Compiler
cpp: make the check of Flex version portable
misc: require getline
c++: support wide strings for file names
doc: document carets
tests: enhance existing tests with carets
errors: show carets
getargs: add support for --flags/-f
Conflicts:
doc/bison.texi
m4/.gitignore
src/complain.c
src/flex-scanner.h
src/getargs.c
src/getargs.h
src/gram.c
src/main.c
tests/headers.at
Forthcoming changes will use the warning categories much more often,
so shortening them will improve readability.
* src/complain.c, src/complain.h, src/conflicts.c,
* src/getargs.c, src/getargs.h, src/gram.c (enum warnings):
s/warnings_/W/g.
This change was made by applying emacs' untabify function to
nearly all files in Bison's repository. Required tabs in make
files, ChangeLog, regexps, and test code were manually skipped.
Other notable exceptions and changes are listed below.
* bootstrap: Skip because we sync this with gnulib.
* data/m4sugar/foreach.m4
* data/m4sugar/m4sugar.m4: Skip because we sync these with
Autoconf.
* djgpp: Skip because I don't know how to test djgpp properly, and
this code appears to be unmaintained anyway.
* README-hacking (Hacking): Specify that tabs should be avoided
where not required.
Reported by George Neuner at
<http://lists.gnu.org/archive/html/bug-bison/2010-08/msg00002.html>.
* NEWS (2.5): Document.
* THANKS (George Neuner): Add.
* doc/bison.texinfo (Bison Options): Document.
* src/complain.c, src/complain.h
(warn_at, warn_at_indent, warn): Suppress warning if -Wno-other.
(midrule_value_at): New warning function, similar to yacc_at in
that it's controlled by its own warning category.
* src/getargs.c (warnings_flag): Initialize to warnings_other.
(warnings_args, warnings_types): Add entry for warnings_other.
(usage): Update.
* src/getargs.h (enum warnings): Add entry for warnings_other.
* src/gram.c (grammar_rules_useless_report): If -Wno-other, then
don't print useless rules.
* src/reader.c (symbol_should_be_used): Rather than adjusting the
return value based on whether midrule value warnings are enabled,
accept a new parameter for telling the caller whether true is
being returned for a potential midrule warning.
(grammar_rule_check): Use midrule_value_at for midrule value
warnings, and continue to use warn_at for all other warnings. Let
them check whether the warnings are enabled.
* tests/local.at (AT_BISON_CHECK): Update documentation.
(AT_BISON_CHECK_NO_XML): Check that -Wnone and --warnings=none
disable all warnings exercised in the test suite.
(cherry picked from commit 8ffd7912e3)
Reported by George Neuner at
<http://lists.gnu.org/archive/html/bug-bison/2010-08/msg00002.html>.
* NEWS (2.5): Document.
* THANKS (George Neuner): Add.
* doc/bison.texinfo (Bison Options): Document.
* src/complain.c, src/complain.h
(warn_at, warn_at_indent, warn): Suppress warning if -Wno-other.
(midrule_value_at): New warning function, similar to yacc_at in
that it's controlled by its own warning category.
* src/getargs.c (warnings_flag): Initialize to warnings_other.
(warnings_args, warnings_types): Add entry for warnings_other.
(usage): Update.
* src/getargs.h (enum warnings): Add entry for warnings_other.
* src/gram.c (grammar_rules_useless_report): If -Wno-other, then
don't print useless rules.
* src/reader.c (symbol_should_be_used): Rather than adjusting the
return value based on whether midrule value warnings are enabled,
accept a new parameter for telling the caller whether true is
being returned for a potential midrule warning.
(grammar_rule_check): Use midrule_value_at for midrule value
warnings, and continue to use warn_at for all other warnings. Let
them check whether the warnings are enabled.
* tests/local.at (AT_BISON_CHECK): Update documentation.
(AT_BISON_CHECK_NO_XML): Check that -Wnone and --warnings=none
disable all warnings exercised in the test suite.
* NEWS (2.4.3): Document fix.
* src/complain.c (error_message): Extend to handle incomplete
error messages so warn and warn_at can be used in more cases.
* src/gram.c (grammar_rules_useless_report): Use warn_at so that
-Werror is always obeyed.
* src/reduce.c (reduce_print): Use warn so that the "warnings
being treated as errors" message is printed consistently before
the first warning message. This makes testing easier.
* tests/local.at (AT_BISON_WERROR_MSG): New macro.
(AT_BISON_CHECK_NO_XML): Extend to check -Werror and
--warnings=error when warnings appear in bison's stderr.
(cherry picked from commit 954474bfa1)
* NEWS (2.4.3): Document fix.
* src/complain.c (error_message): Extend to handle incomplete
error messages so warn and warn_at can be used in more cases.
* src/gram.c (grammar_rules_useless_report): Use warn_at so that
-Werror is always obeyed.
* src/reduce.c (reduce_print): Use warn so that the "warnings
being treated as errors" message is printed consistently before
the first warning message. This makes testing easier.
* tests/local.at (AT_BISON_WERROR_MSG): New macro.
(AT_BISON_CHECK_NO_XML): Extend to check -Werror and
--warnings=error when warnings appear in bison's stderr.
(cherry picked from commit 954474bfa1)
* data/xslt/bison.xsl (xsl:key name="bison:symbolByName"): New.
* data/xslt/xml2xhtml.xsl (xsl:template match="symbol"): Use it to
look up a symbol to determine whether it's a nonterminal or terminal.
* src/gram.c (rule_rhs_print_xml): Remove class attribute.
* src/state.c (state_rule_lookahead_tokens_print_xml): Likewise.
Add prec/assoc information to XML output.
* src/gram.c (grammar_rules_print_xml): For each rule that has a
%prec, add a percent_prec attribute.
* src/print-xml.c (print_grammar): For each terminal that has a
precedence or associativity, add a prec or assoc attribute.
(xml_indent): New.
(xml_puts): Use xml_indent.
(xml_printf): Use xml_indent.
* src/print-xml.h (xml_indent): Prototype.
* tests/existing.at (GNU pic Grammar): Fix a rule miscopied from
<http://lists.gnu.org/archive/html/bug-bison/2003-04/msg00026.html>.
useful ones and add a "usefulness" attribute. Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2007-09/msg00017.html>.
* src/gram.c (grammar_rules_partial_print_xml): Remove.
(grammar_rules_print_xml): Print all rules instead of just those
useful in the grammar, and add a "usefulness" attribute.
* src/gram.h (grammar_rules_partial_print_xml): Remove prototype.
* src/print-xml.c (print_rules_useless_in_parser): Remove.
(print_grammar): Print all nonterminals instead of just useful ones,
and add a "usefulness" attribute to nonterminals and terminals.
(print_xml): Don't print a separate "reductions" or
"rules-useless-in-parser" element.
* src/reduce.c (reduce_output): Use reduce_token_unused_in_grammar.
(reduce_xml): Remove.
(reduce_token_unused_in_grammar): New.
(reduce_nonterminal_useless_in_grammar): New.
* src/reduce.h (reduce_xml): Remove prototype.
(reduce_token_unused_in_grammar): Add prototype.
(reduce_nonterminal_useless_in_grammar): Add prototype.
* data/xslt/xml2text.xsl: Update for XML changes.
* data/xslt/xml2xhtml.xsl: Update for XML changes.
* tests/reduce.at (Useless Terminals): Update output.
(Useless Rules): Update output.
(Reduced Automaton): Update output.
Say "Terminals unused in grammar" instead of "Unused terminals".
* NEWS (2.3a+): Update.
* doc/bison.texinfo (Understanding): Update example output.
* src/reduce.c (reduce_output): Implement.
* data/xslt/xml2text.xsl: Implement.
* data/xslt/xml2xhtml.xsl: Implement.
When reporting useless rules and nonterminals, say "useless in grammar"
instead of "useless", and say "useless in parser" instead of "never
reduced". Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2007-10/msg00033.html>.
* NEWS (2.3a+): Mention this change.
* data/xslt/xml2text.xsl: Update output text and expected input XML
element names to match changes below.
* data/xslt/xml2xhtml.xsl: Likewise.
(xsl:template match="bison-xml-report"): Add missing entry in Table of
Contents: "Rules useless in parser due to conflicts".
* doc/bison.texinfo (Decl Summary): Reword a little.
(Understanding): Update example output for changes below.
* src/gram.c: (rule_useful_p): Rename to...
(rule_useful_in_grammar_p): ... this.
(rule_useless_p): Rename to...
(rule_useless_in_grammar_p): ... this.
(rule_never_reduced_p): Rename to...
(rule_useless_in_parser_p): ... this.
(grammar_rules_print): Update for renames.
(grammar_rules_print_xml): Update for renames.
(grammar_rules_never_reduced_report): Rename to...
(grammar_rules_useless_report): ... this since it is used for either
kind of useless rule.
* src/gram.h: Reword comments and update function names in prototypes.
* src/main.c (main): Say "rule useless in parser due to conflicts".
* src/print-xml.c (print_rules_never_reduced): Rename to...
(print_rules_useless_in_parser): ... this, and rename output XML
element "rules-never-reduced" to "rules-useless-in-parser".
(print_xml): Update for rename.
* src/print.c (print_results): Say "Rules useless in parser due to
conflicts".
* src/reduce.c (reduce_grammar_tables): Say "rule useless in grammar".
(nonterminals_reduce): Say "nonterminal useless in grammar".
(reduce_output): Say "Nonterminals useless in grammar".
Say "Rules useless in grammar".
(reduce_xml): Rename output XML element "useless" to
"useless-in-grammar".
(reduce_print): Don't report the count of grammatically useless rules
as "rules never reduced" just because %yacc is specified.
In the correct report of this count, say nonterminal(s) and rule(s)
"useless in grammar".
* tests/conflicts.at (S/R in initial): Update expected output.
(Defaulted Conflicted Reduction): Likewise.
(Unreachable States After Conflict Resolution): Likewise.
* tests/existing.at (GNU pic Grammar): Likewise.
* tests/reduce.at (Useless Nonterminals): Likewise.
(Useless Rules): Likewise.
(Reduced Automaton): Likewise.
(Underivable Rules): Likewise.
(Empty Language): Likewise.
elsewhere.
* src/print-xml.c: Prefer "const" after types; that's more consistent.
(xml_printf): Indent just 1 space for level.
(e_char, xlate_char): Remove.
(xml_escape_string): Rewrite to avoid undefined behavior (used
storage that was freed from the stack).
(xml_escape_n): Don't bother checking for subscript error.
2007-09-21 Wojciech Polak <polak@gnu.org>
Add support for an -x option to generate an XML report.
It is not documented yet.
* src/print-xml.c: New file.
* src/print-xml.h: Likewise.
* lib/timevar.def (TV_XML): New var.
* src/Makefile.am (bison_SOURCES): Add print-xml.c, print-xml.h.
* src/conflicts.c: Include print-xml.h.
(solved_conflicts_xml_obstack): New var.
(log_resolution, conflicts_solve, conflicts_free):
Add support for XML report.
(conflicts_output_val): New function.
* src/conflicts.h (conflicts_output_val): New decl.
* src/files.c (spec_xml_file): New var.
(compute_output_file_names, output_file_names_free): Add XML support.
* src/files.h (spec_xml_file): New decl.
* src/getargs.c (xml_flag): New var.
(usage, short_options, long_options, getargs): Add XML support.
* src/getargs.h (xml_flag): New decl.
* src/gram.c: Include print-xml.h.
(rule_lhs_print_xml, rule_rhs_print_xml):
(grammar_rules_partial_print_xml, grammar_rules_print_xml):
New functions.
* src/gram.h: Declare external ones.
* src/main.c: Include print-xml.h.
(main): Add XML support.
* src/reduce.c: Include print-xml.h.
(reduce_xml): New function.
* src/reduce.h: Declare it.
* src/state.c: Include print-xml.h.
(state_new): Add XML support.
(state_rule_lookahead_tokens_print_xml): New function.
* src/state.h: Declare it.
(struct state): New member solved_conflicts_xml.
* src/symtab.c (symbol_class_get_string): New function.
* src/symtab.h: Declare it.
2007-09-21 Paul Eggert <eggert@cs.ucla.edu>
* src/reader.c (packgram): Prepend a new sentinel before ritem.
* src/lalr.c (build_relations): Rely on new sentinel.
* src/gram.c (gram_free): Adjust to new sentinel.
