Currently on the following grammar:
%type <foo> foo
%%
start: foo | bar | "baz"
foo: foo
bar: bar
bison reports:
warning: 2 nonterminals useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
1.13-15: warning: nonterminal useless in grammar: foo [-Wother]
%type <foo> foo
^^^
3.14-16: warning: nonterminal useless in grammar: bar [-Wother]
start: foo | bar | "baz"
^^^
[...]
i.e., the location of the first occurrence of a symbol is taken as its
definition point. In the case of nonterminals, the first occurrence
as a left-hand side of a rule makes more sense:
warning: 2 nonterminals useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
4.1-3: warning: nonterminal useless in grammar: foo [-Wother]
foo: foo
^^^
5.1-3: warning: nonterminal useless in grammar: bar [-Wother]
bar: bar
^^^
[...]
* src/symtab.h, src/symtab.c (symbol::location_of_lhs): New.
(symbol_location_as_lhs_set): New.
* src/parse-gram.y (current_lhs): Use it.
* tests/reduce.at: Update locations.
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.
* 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.
* 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
* tests/actions.at: Unset value.
* tests/conflicts.at: Rule useless due to conflicts.
* tests/input.at: Missing terminator, unexpected end of file, command line
redefinition of variable.
* tests/named-refs.at: Many errors.
* tests/reduce.at: Useless nonterminals and rules.
* tests/regression.at: Large token.
* origin/maint:
tests: close files in glr-regression
xml: match DOT output and xml2dot.xsl processing
xml: factor xslt space template
graph: fix a memory leak
xml: documentation
output: capitalize State
The current routines used to display s/r and r/r conflicts are both
inconvenient from the programmer point of view (they do not use the
warning infrastructure) and for the user (the messages are rather
terse, not necessarily pleasant to read, and because they don't use
the same routines, they look different).
It was due to the belief (dating back to the initial checked-in
version of Bison) that, at some point, POSIX Yacc mandated the format
for these messages. Today, the Open Group's manual page for Yacc,
<http://pubs.opengroup.org/onlinepubs/009695399/utilities/yacc.html>,
explicitly states that the format of these messages is unspecified.
See commit be7280480c and
<http://lists.gnu.org/archive/html/bison-patches/2002-12/msg00027.html>.
For a discussion on the chosen warning format, see
http://lists.gnu.org/archive/html/bison-patches/2012-09/msg00039.html
In an effort to factor the handling of errors and warnings, use the
Bison warning routines to report these messages.
* src/conflicts.c (conflicts_print): Rewrite with clearer sections
about S/R and then R/R conflicts.
(conflict_report): Remove, inlined in its sole
caller...
(conflicts_output): here.
* tests/conflicts.at, tests/existing.at, tests/glr-regression.at,
* tests/reduce.at, tests/regression.at: Adjust the expected results.
* NEWS: Update.
States that shift the error token do not have default reductions,
and GLR disables some default reductions, so "all" was a misnomer.
* doc/bison.texinfo (%define Summary): Update.
(Default Reductions): Update.
* src/print.c (print_reductions): Update.
* src/reader.c (prepare_percent_define_front_end_variables):
Update.
* src/tables.c (action_row): Update.
* tests/input.at (%define enum variables): Update.
* tests/reduce.at (%define lr.default-reductions): Update.
(cherry picked from commit d815ec4a62)
States that shift the error token do not have default reductions,
and GLR disables some default reductions, so "all" was a misnomer.
* doc/bison.texinfo (%define Summary): Update.
(Default Reductions): Update.
* src/print.c (print_reductions): Update.
* src/reader.c (prepare_percent_define_front_end_variables):
Update.
* src/tables.c (action_row): Update.
* tests/input.at (%define enum variables): Update.
* tests/reduce.at (%define lr.default-reductions): Update.
For now, just api.push-pull and lr.keep-unreachable-states.
Maintain old names for backward compatibility.
* NEWS (2.5): Document.
* data/c.m4 (b4_identification): Update comment.
* data/yacc.c: Update access.
* doc/bison.texinfo: Update.
* etc/bench.pl.in (bench_push_parser): Update use.
* src/files.c (tr): Move to...
* src/getargs.c, src/getargs.h (tr): ... here because I can't
think of a better place to expose it. My logic is that, for all
uses of tr so far, command-line arguments can be involved, and
getargs.h is already included.
* src/main.c (main): Update access.
* src/muscle_tab.c (muscle_percent_define_insert): Convert old
variable names to new variable names before assigning value.
* src/reader.c (reader): Update setting default.
* tests/calc.at: Update uses.
* tests/conflicts.at (Unreachable States After Conflict
Resolution): Update use.
* tests/input.at (%define enum variables): Update use.
(%define backward compatibility): New test group.
* tests/push.at: Update uses.
* tests/reduce.at: Update uses.
* tests/torture.at: Update uses.
(cherry picked from commit 812775a039)
Conflicts:
data/c.m4
etc/bench.pl.in
src/parse-gram.c
src/parse-gram.h
tests/conflicts.at
For now, just api.push-pull and lr.keep-unreachable-states.
Maintain old names for backward compatibility.
* NEWS (2.5): Document.
* data/c.m4 (b4_identification): Update comment.
* data/yacc.c: Update access.
* doc/bison.texinfo: Update.
* etc/bench.pl.in (bench_grammar): Update use.
* src/files.c (tr): Move to...
* src/getargs.c, src/getargs.h (tr): ... here because I can't
think of a better place to expose it. My logic is that, for all
uses of tr so far, command-line arguments can be involved, and
getargs.h is already included.
* src/main.c (main): Update access.
* src/muscle_tab.c (muscle_percent_define_insert): Convert old
variable names to new variable names before assigning value.
* src/reader.c (reader): Update setting default.
* tests/calc.at: Update uses.
* tests/conflicts.at (Unreachable States After Conflict
Resolution): Update use.
* tests/input.at (%define enum variables): Update use.
(%define backward compatibility): New test group.
* tests/push.at: Update uses.
* tests/reduce.at: Update uses.
* tests/torture.at: Update uses.
Its value can be "LALR", "IELR", or "canonical LR".
* lib/timevar.def (TV_IELR_PHASE1): New var.
(TV_IELR_PHASE2): New var.
(TV_IELR_PHASE3): New var.
(TV_IELR_PHASE4): New var.
* src/local.mk (src_bison_SOURCES): Add AnnotationList.c,
AnnotationList.h, InadequacyList.c, InadequacyList.h, Sbitset.c,
Sbitset.h, ielr.c, and ielr.h.
* src/getargs.h, src/getargs.c (enum trace, trace_args,
trace_types): Add trace_ielr.
* src/lalr.h, src/lalr.c (ngotos): Export it.
(F): Rename to...
(goto_follows): ... this, update all uses, and export it.
(set_goto_map): Export it.
(map_goto): Export it.
(compute_lookahead_tokens): Don't free goto_follows yet. Now
handled in ielr.
(initialize_LA): Export it. Move lookback allocation to...
(lalr): ... here because, for canonical LR, initialize_LA must
be invoked but lookback and much of the rest of LALR isn't
needed.
* main.c (main): Instead of lalr, invoke ielr, which invokes
lalr.
* src/reader.c (reader): Default lr.type to "LALR".
Default lr.default_rules to "accepting" if lr.type is "canonical
LR". Leave the default as "all" otherwise.
Check for a valid lr.type value.
* src/state.h, src/state.c (struct state_list): Add state_list
member.
(state_new): Initialize state_list member to NULL.
(state_new_isocore): New function, exported.
* tests/existing.at (AT_TEST_EXISTING_GRAMMAR): New macro that
exercises all values of lr.type.
(GNU AWK Grammar): Rename test group to...
(GNU AWK 3.1.0 Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
(GNU Cim Grammar): Extend to use AT_TEST_EXISTING_GRAMMAR.
(GNU pic Grammar): Rename test group to...
(GNU pic (Groff 1.18.1) Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
* tests/reduce.at (AT_TEST_LR_TYPE): New macro that exercises
all values of lr.type.
(Single State Split): New test groups using AT_TEST_LR_TYPE.
(Lane Split): Likewise.
(Complex Lane Split): Likewise.
(Split During Added Lookahead Propagation): Likewise.
Its value describes the states that are permitted to contain
default rules: "all", "consistent", or "accepting".
* src/reader.c (reader): Default lr.default_rules to "all".
Check for a valid lr.default_rules value.
* src/lalr.c (state_lookahead_tokens_count): If lr.default_rules
is "accepting", then only mark the accepting state as
consistent.
(initialize_LA): Tell state_lookahead_tokens_count whether
lr.default_rules is "accepting".
* src/tables.c (action_row): If lr.default_rules is not "all",
then disable default rules in inconsistent states.
* src/print.c (print_reductions): Use this opportunity to
perform some assertions about whether lr.default_rules was
obeyed correctly.
* tests/local.at (AT_TEST_TABLES_AND_PARSE): New macro that
helps with checking the parser tables for a grammar.
* tests/input.at (%define lr.default_rules invalid values): New
test group.
* tests/reduce.at (AT_TEST_LR_DEFAULT_RULES): New macro using
AT_TEST_TABLES_AND_PARSE.
(`no %define lr.default_rules'): New test group generated by
AT_TEST_LR_DEFAULT_RULES.
(`%define lr.default_rules "all"'): Likewise.
(`%define lr.default_rules "consistent"'): Likewise.
(`%define lr.default_rules "accepting"'): Likewise.
Its value can be "LALR", "IELR", or "canonical LR".
* lib/timevar.def (TV_IELR_PHASE1): New var.
(TV_IELR_PHASE2): New var.
(TV_IELR_PHASE3): New var.
(TV_IELR_PHASE4): New var.
* src/Makefile.am (bison_SOURCES): Add AnnotationList.c,
AnnotationList.h, InadequacyList.c, InadequacyList.h, Sbitset.c,
Sbitset.h, ielr.h, and ielr.c.
* src/getargs.h, src/getargs.c (enum trace, trace_args,
trace_types): Add trace_ielr.
* src/lalr.h, src/lalr.c (ngotos): Export it.
(F): Rename to...
(goto_follows): ... this, update all uses, and export it.
(set_goto_map): Export it.
(map_goto): Export it.
(compute_lookahead_tokens): Don't free goto_follows yet. Now
handled in ielr.
(initialize_LA): Export it. Move lookback allocation to...
(lalr): ... here because, for canonical LR, initialize_LA must
be invoked but lookback and much of the rest of LALR isn't
needed.
* main.c (main): Instead of lalr, invoke ielr, which invokes
lalr.
* src/reader.c (reader): Default lr.type to "LALR".
Default lr.default_rules to "accepting" if lr.type is "canonical
LR". Leave the default as "all" otherwise.
Check for a valid lr.type value.
* src/state.h, src/state.c (struct state_list): Add state_list
member.
(state_new): Initialize state_list member to NULL.
(state_new_isocore): New function, exported.
* tests/existing.at (AT_TEST_EXISTING_GRAMMAR): New macro that
exercises all values of lr.type.
(GNU AWK Grammar): Rename test group to...
(GNU AWK 3.1.0 Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
(GNU Cim Grammar): Extend to use AT_TEST_EXISTING_GRAMMAR.
(GNU pic Grammar): Rename test group to...
(GNU pic (Groff 1.18.1) Grammar): ... this, and extend to use
AT_TEST_EXISTING_GRAMMAR.
* tests/reduce.at (AT_TEST_LR_TYPE): New macro that exercises
all values of lr.type.
(Single State Split): New test groups using AT_TEST_LR_TYPE.
(Lane Split): Likewise.
(Complex Lane Split): Likewise.
(Split During Added Lookahead Propagation): Likewise.
Its value describes the states that are permitted to contain
default rules: "all", "consistent", or "accepting".
* src/reader.c (reader): Default lr.default_rules to "all".
Check for a valid lr.default_rules value.
* src/lalr.c (state_lookahead_tokens_count): If lr.default_rules
is "accepting", then only mark the accepting state as
consistent.
(initialize_LA): Tell state_lookahead_tokens_count whether
lr.default_rules is "accepting".
* src/tables.c (action_row): If lr.default_rules is not "all",
then disable default rules in inconsistent states.
* src/print.c (print_reductions): Use this opportunity to
perform some assertions about whether lr.default_rules was
obeyed correctly.
* tests/local.at (AT_TEST_TABLES_AND_PARSE): New macro that
helps with checking the parser tables for a grammar.
* tests/input.at (%define lr.default_rules invalid values): New
test group.
* tests/reduce.at (AT_TEST_LR_DEFAULT_RULES): New macro using
AT_TEST_TABLES_AND_PARSE.
(`no %define lr.default_rules'): New test group generated by
AT_TEST_LR_DEFAULT_RULES.
(`%define lr.default_rules "all"'): Likewise.
(`%define lr.default_rules "consistent"'): Likewise.
(`%define lr.default_rules "accepting"'): Likewise.
Reported by Goran Uddeborg at
<http://lists.gnu.org/archive/html/bug-bison/2008-06/msg00000.html>.
* THANKS (Goran Uddeborg): Add.
* src/reduce.c (reduce_print): Report the number of nonterminals and
rules useless in the grammar in separate sentences.
* tests/reduce.at (Useless Rules): Update output.
(Reduced Automaton): Likewise.
(Underivable Rules): Likewise.
(Empty Language): Likewise.
starting at
<http://lists.gnu.org/archive/html/bison-patches/2007-11/msg00021.html>.
* configure.ac (XSLTPROC): New substitution.
* Makefile.am (maintainer-xml-check): New phony target invoking...
* tests/Makefile.am (maintainer-xml-check): ... this new phony target
invoking make maintainer-check with BISON_TEST_XML=1.
* tests/atlocal.in (XSLTPROC): New.
* tests/local.at (AT_BISON_CHECK): New macro to (1) instruct Valgrind
not to report reachable memory when Bison is expected to have a
non-zero exit status and (2) to compare XML/XSLT output with --graph
and --report=all output for every working grammar when
BISON_TEST_XML=1.
(AT_BISON_CHECK_NO_XML): Likewise, but skip XML checks.
(AT_BISON_CHECK_XML): New.
(AT_QUELL_VALGRIND): New.
* tests/testsuite.at (ORIGINAL_AT_CHECK): Remove this and...
(AT_CHECK): ... don't redefine this since this was the old way to
quell Valgrind.
* tests/actions.at: Rewrite all AT_CHECK invocations for bison as
AT_BISON_CHECK invocations.
* tests/c++.at: Likewise.
* tests/calc.at: Likewise.
* tests/conflicts.at: Likewise.
* tests/cxx-type.at: Likewise.
* tests/existing.at: Likewise.
* tests/glr-regression.at: Likewise.
* tests/headers.at: Likewise.
* tests/input.at: Likewise.
* tests/java.at: Likewise.
* tests/output.at: Likewise.
* tests/push.at: Likewise.
* tests/reduce.at: Likewise.
* tests/regression.at: Likewise.
* tests/sets.at: Likewise.
* tests/skeletons.at: Likewise.
* tests/synclines.at: Likewise.
* tests/torture.at: Likewise.
(Big triangle): Use AT_BISON_CHECK_NO_XML instead since this grammar
tends to hang xsltproc.
(Big horizontal): Likewise.
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.
