Reported by Rici Lake.
http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00000.html
* src/complain.h: Formatting change.
* src/parse-gram.y (id): Reject character literals used in a context
for non-terminals.
* tests/input.at (Invalid %nterm uses): Check that.
This change allows one to document (and check) which rules participate
in shift/reduce and reduce/reduce conflicts. This is particularly
important GLR parsers, where conflicts are a normal occurrence. For
example,
%glr-parser
%expect 1
%%
...
argument_list:
arguments %expect 1
| arguments ','
| %empty
;
arguments:
expression
| argument_list ',' expression
;
...
Looking at the output from -v, one can see that the shift-reduce
conflict here is due to the fact that the parser does not know whether
to reduce arguments to argument_list until it sees the token AFTER the
following ','. By marking the rule with %expect 1 (because there is a
conflict in one state), we document the source of the 1 overall shift-
reduce conflict.
In GLR parsers, we can use %expect-rr in a rule for reduce/reduce
conflicts. In this case, we mark each of the conflicting rules. For
example,
%glr-parser
%expect-rr 1
%%
stmt:
target_list '=' expr ';'
| expr_list ';'
;
target_list:
target
| target ',' target_list
;
target:
ID %expect-rr 1
;
expr_list:
expr
| expr ',' expr_list
;
expr:
ID %expect-rr 1
| ...
;
In a statement such as
x, y = 3, 4;
the parser must reduce x to a target or an expr, but does not know
which until it sees the '='. So we notate the two possible reductions
to indicate that each conflicts in one rule.
See https://lists.gnu.org/archive/html/bison-patches/2013-02/msg00105.html.
* doc/bison.texi (Suppressing Conflict Warnings): Document %expect,
%expect-rr in grammar rules.
* src/conflicts.c (count_state_rr_conflicts): Adjust comment.
(rule_has_state_sr_conflicts): New static function.
(count_rule_sr_conflicts): New static function.
(rule_nast_state_rr_conflicts): New static function.
(count_rule_rr_conflicts): New static function.
(rule_conflicts_print): New static function.
(conflicts_print): Also use rule_conflicts_print to report on individual
rules.
* src/gram.h (struct rule): Add new fields expected_sr_conflicts,
expected_rr_conflicts.
* src/reader.c (grammar_midrule_action): Transfer expected_sr_conflicts,
expected_rr_conflicts to new rule, and turn off in current_rule.
(grammar_current_rule_expect_sr): New function.
(grammar_current_rule_expect_rr): New function.
(packgram): Transfer expected_sr_conflicts, expected_rr_conflicts
to new rule.
* src/reader.h (grammar_current_rule_expect_sr): New function.
(grammar_current_rule_expect_rr): New function.
* src/symlist.c (symbol_list_sym_new): Initialize expected_sr_conflicts,
expected_rr_conflicts.
* src/symlist.h (struct symbol_list): Add new fields expected_sr_conflicts,
expected_rr_conflicts.
* tests/conflicts.at: Add tests "%expect in grammar rule not enough",
"%expect in grammar rule right.", "%expect in grammar rule too much."
We also lack a consistent naming for directive implementations.
`directive_skeleton` is too long, `percent_skeleton` is not very nice
looking, `process_skeleton` looks ambiguous, `do_skeleton` is somewhat
ambiguous too, but seems a better track.
* src/parse-gram.y (version_check): Rename as...
(do_require): this.
(do_skeleton): New.
Use it.
It is unfortunate that %error_verbose was properly diagnosed as
obsoleted by "%define parse.error verbose", but %error-verbose was
not.
* src/parse-gram.y (%error-verbose): Remove support.
* src/scan-gram.l: Do it here instead, with a warning.
* tests/input.at (Deprecated directives): Check it.
* src/parse-gram.y (api.value.type): Set to union.
Replace occurrences of %union with explicit %types.
* src/scan-gram.l: Adjust yylval's field names.
(RETURN_VALUE): No longer needs the Field argument.
Use it more.
The files stack.hh and position.hh are deprecated. Rather than
devoting specify %define variables to discard them (api.position.file
and api.stack.file), and rather than having to use special rules when
api.location.file is used, let's simply decide that from %require
"3.2" onwards, these files will not be generated.
The only noticeable thing here is that, in order to be able to check
the behavior of %require "3.2", to have this version (which is still
3.1-*) to accept %require "3.2".
* src/gram.h, src/gram.c (required_version): New.
* src/parse-gram.y (version_check): Set it.
* src/output.c (prepare): Pass it m4.
* data/bison.m4 (b4_required_version_if): Receive it and use it.
* data/location.cc, data/stack.hh: Replace the api.*.file with only
required version comparison.
* tests/input.at: No longer check api.stack.file and api.position.file.
* NEWS, doc/bison.texi: Don't mention them.
Document the %require 3.2 behavior.
* tests/output.at: Use %require 3.2 instead.
Prompted on Piotr Marcińczyk's message:
http://lists.gnu.org/archive/html/bug-bison/2017-06/msg00000.html.
See also http://lists.gnu.org/archive/html/bug-bison/2018-06/msg00001.html.
Because their type is unknown to Bison, the values of midrule actions are
not treated like the others: they don't have %printer and %destructor
support. In addition, in C++, (Bison) variants cannot work properly.
Typed midrule actions address these issues. Instead of:
exp: { $<ival>$ = 1; } { $<ival>$ = 2; } { $$ = $<ival>1 + $<ival>2; }
write:
exp: <ival>{ $$ = 1; } <ival>{ $$ = 2; } { $$ = $1 + $2; }
* src/scan-code.h, src/scan-code.l (code_props): Add a `type` field to
record the declared type of an action.
(code_props_rule_action_init): Add a type argument.
* src/parse-gram.y: Accept an optional type tag for actions.
* src/reader.h, src/reader.c (grammar_current_rule_action_append): Add
a type argument.
(grammar_midrule_action): When a mid-rule is typed, pass its type to
the defined dummy non terminal symbol.
grammar_current_rule_action_append was used in two different places:
for actual action (`{...}`), and for predicates (`%?{...}`). Let's
split this in two different functions.
* src/reader.h, src/reader.c (grammar_current_rule_predicate_append): New.
Extracted from...
(grammar_current_rule_action_append): here.
Remove arguments that don't apply.
Adjust dependencies.
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.
Bison supports a union tag, for obscure reasons. But it does a poor
job at it, especially since Bison 3.0.
Reported by Stephen Cameron and Tobias Frost.
It did not ensure that the name was not given several times. An easy
way to do this is to make the %union tag be handled as a %define
variable, as they cannot be defined several times.
Since Bison 3.0, the synclines were wrongly placed, resulting in
invalid code. Addressing this issue, because of the way the union tag
was stored (as a code muscle), would have been tedious. Unless we
rather define the %union tag as a %percent variable, whose synclines
are easier to manipulate.
So replace the b4_union_name muscle by the api.value.union.name
%define variable, document, and check.
* data/bison.m4: Make sure that api.value.union.name has a keyword value.
* data/c++.m4: Make sure that api.value.union.name is not defined.
* data/c.m4 (b4_union_name): No longer use it, use api.value.union.name.
* doc/bison.texi (%define Summary): Document it.
* src/parse-gram.y (union_name): No longer define b4_uion_name, but
api.value.union.name.
* tests/input.at (Redefined %union name): New.
* tests/synclines.at (%union name syncline): New.
* tests/types.at: Check named %unions.
Using %code for config.h is wrong, as some headers will already have
been included by Bison. In some cases, e.g., glibc's string.h, this
results in some declaration not being made for lack of definition of
_GNU_SOURCE, which is performed by config.h.
* src/parse-gram.y: here.
The purpose of this symbol was only to factor function calls. As a
result the actions were indeed simpler, but the grammar was somewhat
uselessly obfuscated. Get rid of this symbol, but introduce functions
to simplify dependencies.
There is no (intended) changes of behavior here.
* src/parse-gram.y (strip_braces, translate_code(
(translate_code_braceless): New.
(braceless): Remove, use "{...}" instead, and one of the previous
functions depending on the context.
(STRING, "%{...%}", EPILOGUE): Declare as <code>, instead of <chars>,
the difference between both is useless (well, I couldn't make sense of
it, even after having read the initial commit that introduced them).
(%union): Remove the now useless "chars" type.
Adjust the printers.
* src/scan-gram.l: Adjust.
* src/parse-gram.y (version_check, gram_error, char_name, lloc_default):
Move their prototypes from %{...%} to %code.
(YYLLOC_DEFAULT, YY_LOCATION_PRINT): Move from %{...%} to %code.
(current_lhs): Move its implementation to the epilogue.
Now that we use "braceless" (which is {...} blocks of code with
initial and final braces stripped) to denote "short" values (such as
api.namespaces), the added end-of-line is a nuisance. As a matter of
fact, this extra-safety was useless, as every expansion of "braceless"
(aka, "user code") is followed by an end of line.
* src/parse-gram.y, src/parse-gram.c (braceless): Instead of replacing
the final brace by \n, just delete the brace.
Provide a means to tell the difference between "keyword" values (e.g.,
%define api.pull both), "string" values (e.g., %define file.name
"foo"), and "code" values (e.g., %define api.namespace {calc}).
Suggested by Joel E. Denny.
http://lists.gnu.org/archive/html/bison-patches/2013-03/msg00016.html
* src/muscle-tab.h, src/muscle-tab.c (muscle_kind, muscle_kind_new)
(muscle_kind_string): New.
(muscle_percent_define_insert): Take the kind as new argument.
Insert it in the muscle table.
Adjust callers.
* src/getargs.c: Adjust callers.
* src/parse-gram.y: Ditto.
(content.opt): Remove, replaced by...
(value): this new non-terminal, whose semantics value is stored
in the new "value" union member.
Provide a printer.
Support values in braces in additions to keyword and string values.
fuse me
* src/parse-gram.y (PARAM_TYPE): Remove useless typedef guard.
There's a header guard.
Use 'yyo' with %printer.
Use a consistent style for %union one-liners.
* src/parse-gram.y (INT): Fuse the %type and %token declaration.
Move its %union right before its introduction.
(%union): Split in several %unions, right before their use.
In a precedence declaration, when tokens are declared with a litteral
character (e.g., 'a') or with a identifier (e.g., B), Bison behaved
differently: the litteral tokens would be numbered first, and then the
other ones, leading to the following grammar:
%right A B 'c' 'd'
being numbered as such: 'c' 'd' A B.
* src/parse-gram.y (symbol.prec): Set the symbol number when reading the
symbols.
* tests/conflicts.at (Token declaration order: literals vs. identifiers):
New.
Signed-off-by: Akim Demaille <akim@lrde.epita.fr>
Provide a means to explicitly denote empty right-hand sides of rules:
instead of
exp: { ... }
allow
exp: %empty { ... }
Make sure that %empty is properly used.
With help from Joel E. Denny and Gabriel Rassoul.
http://lists.gnu.org/archive/html/bison-patches/2013-01/msg00142.html
* src/reader.h, src/reader.c (grammar_current_rule_empty_set): New.
* src/parse-gram.y (%empty): New token.
Use it.
* src/scan-gram.l (%empty): Scan it.
* src/reader.c (grammar_rule_check): Check that %empty is properly used.
* tests/actions.at (Invalid uses of %empty, Valid uses of %empty): New.
"stype" is quite unclear, and it also collides with the former %define
variable that had the same name (replaced by api.value.type).
* src/parse-gram.y (stype): Rename as...
(union_members): this.
* data/bison.m4: Adjust.
(b4_user_stype): Rename as...
(b4_user_union_members): this.
* data/c++.m4, data/c.m4: Adjust.
* src/parse-gram.c: regen.
* src/location.h, src/location.c (location_print): For consistency
with other data structures and other location_* routines, pass the
location argument first.
* src/complain.c: Adjust.
(location_caret): Likewise.
* src/parse-gram.y: Adjust.
In a declaration %token A B, the token A is declared before B, but in %left
A B (or with %precedence or %nonassoc or %right), the token B was declared
before A (tokens were declared in reverse order).
* src/symlist.h, src/symlist.c (symbol_list_append): New.
* src/parse-gram.y: Use it instead of symbol_list_prepend.
* tests/input.at: Adjust expectations.
* origin/maint: (46 commits)
doc: minor style change
maint: use gendocs's new -I option
regen
yacc.c: do not define location support when not using locations
maint: be compilable with GCC 4.0
tests: address a warning from GCC 4.4
tests: don't use options that Clang does not support
tests: restore the tests on -Werror
regen
parse-gram: update the Bison interface
fix comment
maint: post-release administrivia
version 2.6.4
regen
2.6.4: botched 2.6.3
maint: post-release administrivia
version 2.6.3
gnulib: update
tests: check %no-lines
NEWS: warnings with clang
...
Conflicts:
NEWS
TODO
data/c.m4
data/java.m4
doc/Makefile.am
src/getargs.c
src/getargs.h
src/output.c
src/parse-gram.c
src/parse-gram.h
src/parse-gram.y
src/reader.h
The "shadows a global declaration" warning in GCC 4.0 was a bit
annoying. It does not like that a type name be used in a prototype of
a function (not the implementation, just the declaration):
In file included from src/LR0.c:38:
src/reader.h:56: warning: declaration of 'named_ref' shadows a
global declaration
src/named-ref.h:35: warning: shadowed declaration is here
It does not like either when a global variable name is used in a
prototype. Flex 2.5.37 generates this prototype:
void gram_set_debug (int debug_flag );
* src/getargs.h, src/getargs.c (debug_flag): Rename as...
(debug): this.
Adjust dependencies.
* src/reader.h: Don't use "named_ref" as a formal argument name.
* origin/maint:
maint: remove useless file
update files to ignore
remove useless include
use locale-indep. c_is* functions for parsing, not isspace, isprint etc
gnulib: update
--help: include a place to report translation issues
tests: style changes
tests: fix push-pull test
yacc.c: style changes
Conflicts:
src/system.h
