A "symbol" groups together the symbol type (INT, PLUS, etc.), its
possible semantic value, and its optional location. The type is
needed to access the value, as it is stored as a variant/union.
There are two kinds of symbols. "symbol_type" are "external symbols":
they have type, value and location, and are returned by yylex.
"stack_symbol_type" are "internal symbols", they group state number,
value and location, and are stored in the parser stack. The type of
the symbol is computed from the state number.
The class template symbol_base_type<Exact> factors the code common to
stack_symbol_type and symbol_type. It uses the Curiously Recurring
Template pattern so that we can always (static_) downcast to the exact
type. symbol_base_type features value and location, and delegates the
handling of the type to its parameter.
When trying to generalize the support for variant, a significant issue
was revealed: because stack_symbol_type and symbol_type _derive_ from
symbol_base_type, the type/state member is defined _after_ the value
and location. In C++ the order of the definition of the members
defines the order in which they are initialized, things go backward:
the value is initialized _before_ the type. This is wrong, since the
type is needed to access the value.
Therefore, we need another means to factor the common code, one that
ensures the order of the members.
The idea is simple: define two (base) classes that code the symbol
type ("by_type" codes it by its type, and "by_state" by the state
number). Define basic_symbol<Base> as the class template that
provides value and location support. Make it _derive_ from its
parameter, by_type or by_state. Then define stack_symbol_type and
symbol_type as basic_symbol<by_state>, basic_symbol<by_type>. The
name basic_symbol was chosen by similarity with basic_string and
basic_ostream.
* data/c++.m4 (symbol_base_type<Exact>): Remove, replace by...
(basic_symbol<Base>): which derives from its parameter, one of...
(by_state, by_type): which provide means to retrieve the actual type of
symbol.
(symbol_type): Is now basic_symbol<by_type>.
(stack_symbol_type): Is now basic_symbol<by_state>.
* data/lalr1.cc: Many adjustments.
This is consistent with the other %define variable names.
* data/java.m4: Use api.value.type instead of stype.
* doc/bison.texi, NEWS: Document that change.
* src/muscle-tab.c (muscle_percent_variable_update): Provide backward
compatibility.
* tests/java.at: Adjust.
So far we were issuing two lines for each syncline change:
/* Line 356 of yacc.c */
#line 1 "src/parse-gram.y"
This is a lot of clutter, especially when reading diffs, as these
lines change often. Fuse them into a single, shorter, line:
#line 1 "src/parse-gram.y" /* yacc.c:356 */
* data/bison.m4 (b4_syncline): Issue a single line.
Comment improvements.
(b4_sync_start, b4_sync_end): Issue a shorter comment.
* data/c++.m4 (b4_semantic_type_declare): b4_user_code must be
on its own line as it might start with a "#line" directive.
The commit 38de4e570f underquoted the
content of the comments, which resulted in losing square brackets in
the comments. Besides, some other invocations were underquoting the
effective arguments.
* data/c.m4 (b4_comment_): Properly quote the comment.
(b4_comment_, b4_comment): Move to...
* data/c-like.m4: here, so that...
* data/java.m4: can use it instead of its own copy.
* data/bison.m4 (b4_integral_parser_tables_map): Fix some comments.
* data/lalr1.cc, data/lalr1.java, data/yacc.c: Comment fixes.
* data/lalr1.cc: Reorder a bit to factor some CPP directives.
The YYLEX existed only to support YYLEX_PARAM, which is now removed.
This macro was a nuisance, since incorrect yylex calls where pointed
the macro _use_, instead of its definition.
* data/c.m4 (b4_lex_formals, b4_lex): New.
* data/glr.c, data/yacc.c: Use it.
* data/lalr1.cc (b4_lex): New.
Use it.
squash! skeletons: no longer call yylex via a CPP macro
* data/c.m4 (b4_token_enum): Improve comments.
(b4_value_type_define, b4_location_type_define): New, extracted
from...
(b4_declare_yylstype): here.
Separate the typedefs from the union/struct definitions.
* src/muscle-tab.c (define_directive): Be robust to "assignment"
containing '='.
(muscle_percent_variable_update): Upgrade "variant" to "api.value.type".
Support such upgrade patterns.
Adjust callers.
* data/bison.m4: Use api.value.type for variants.
* tests/c++.at: Adjust tests.
This is mostly used for the license header, the synclines, and the
generated tables:
- /* STOS_[STATE-NUM] -- The (internal number of the) accessing
- symbol of state STATE-NUM. */
+ // STOS_[STATE-NUM] -- The (internal number of the) accessing
+ // symbol of state STATE-NUM.
static const unsigned char yystos_[];
* data/c.m4: Comment changes.
(b4_comment_): Expand the text argument.
Before this change, we were actually formatting M4 code as a
C comment, and then expand it.
(b4_comment): Fix the closing of comments: there is no reason to
add the (line) prefix before the closing "*/".
* data/c++.m4 (b4_comment): New.
The "variant" structure provides a means to store, in a typeless way,
C++ objects. Manipulating it without provide the type of the stored
content is doomed to failure. So provide a means to copy in a type
safe way, and prohibit typeless assignments.
* data/c++.m4 (symbol_type::move): New.
* data/lalr1.cc: Use it.
* data/variant.hh (b4_variant_define): Provide variant::copy.
Let variant::operator= abort.
We cannot undefine it, yet, as it is still uses by the implicit
assigment in symbols, which must also be disabled.
Equip variants with more checking code. Provide a means to request
includes.
* data/variant.hh (b4_variant_includes): New.
* data/lalr1.cc: Use it.
* data/variant.hh (variant::built): Define at the end, as a private member.
(variant::tname): New.
Somewhat makes "built" useless, but let's keep both for a start, in
case using "typeinfo" is considered unacceptable in some environments.
Fix some formatting issues.
The fact that glr.cc uses glr.c makes the handling of parse params
more complex, as the parser object of glr.cc must be passed to the
parse function of glr.c. Yet not all the functions need access to
the parser object.
* data/glr.cc (b4_parse_param_wrap): New.
Use them.
* data/glr.c, src/graphviz.h, src/ielr.c, src/scan-gram.l,
* src/system.h, tests/actions.at, tests/glr-regression.at: Do not
use // comments.
Do not introduce variables after statements.
Provide "main" with a return value.
* 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
* origin/maint:
parser: accept #line NUM
m4: use a safer pattern to enable/disable output
tests: beware of gnulib's need for config.h
gnulib: update
yacc.c, glr.c: check and fix the display of locations
formatting changes
glr.c: remove stray macro
Conflicts:
data/c.m4
data/glr.cc
data/lalr1.cc
data/lalr1.java
data/location.cc
data/stack.hh
data/yacc.c
src/scan-gram.l
Work on some other areas of Bison revealed that some macros expanded
to be expanded only once were actually expanded several times. This
was due to the fact that changecom was not properly restored each
time, and macro names appearing in comments were then expanded.
Introduce begin/end macros which are easier to match that
changecom()/changecom(#).
* data/bison.m4 (b4_output_begin, b4_output_end): New.
* data/glr.c, data/glr.cc, data/lalr1.cc, data/lalr1.java,
* data/location.cc, data/stack.hh, data/yacc.c:
Use them.
In some case, negative column number could be displayed.
Make YY_LOCATION_PRINT similar to bison's own implementation of
locations. Since the macro is getting fat, make it a static
function.
Reported by Jonathan Fabrizio.
* data/c.m4 (yy_location_print_define): Improve the implementation,
and generate the yy_location_print_ function.
Adjust YY_LOCATION_PRINT.
* tests/actions.at (Location Print): New tests.
* data/c.m4: Fix comments, put macros in a more natural order.
Space changes (from M-x whitespace-cleanup).
* src/location.c: Fix spaces.
* tests/actions.at: Space changes.
This makes the interface for yyerror() pure without the need for a spurious
parse_param.
* data/yacc.c (b4_pure_if, b4_pure_flag): New definition, accept three states.
(b4_yacc_pure_if): Rename as...
(b4_yyerror_arg_loc_if): This, and use b4_pure_flag.
* tests/actions.at (%define api.pure): Modernize.
* test/calc.at (Simple LALR Calculator): Modernize.
* tests/local.at (AT_YYERROR_ARG_LOC_IF): Adjust.
* origin/maint:
yacc.c: always initialize yylloc
scanner: issue a single error for groups of invalid characters
tests: formatting changes
doc: one of the fixes for an ambiguous grammar was ambiguous too
doc: fix the dangling else with precedence directives
doc: prefer "token" to TOKEN
doc: formatting changes
scanner: use explicit "ignore" statements
Conflicts:
src/scan-gram.l
* origin/branch-2.6:
yacc.c: always initialize yylloc
doc: one of the fixes for an ambiguous grammar was ambiguous too
doc: fix the dangling else with precedence directives
doc: prefer "token" to TOKEN
doc: formatting changes
Conflicts:
NEWS
doc/bison.texi
The initial location might be used if the parser starts by an empty
reduction, so really ensure proper initialization of the initial
location. The previous approach fails for PostgreSQL, which uses
Reported by Peter Eisentraut.
http://lists.gnu.org/archive/html/bug-bison/2012-11/msg00023.html
With help from Théophile Ranquet.
* data/yacc.c (b4_declare_scanner_communication_variables): Be sure
to initialize yylloc, even when its structure is unknown.
(yyparse): Simplify the call to b4_dollar_pushdef.
* tests/actions.at (Initial location): Check of similar pattern
as in the case of PostgreSQL.
* 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
Make the DOT produced by XSLT processing equivalent to the one made with the
--graph option.
* data/xslt/xml2dot.xsl: Stylistic changes, and add support for reductions.
* doc/bison.texi (Xml): Update.
* src/graphviz.c (conclude_red): Minor stylistic changes to DOT internals.
(output_red): Swap enabled and disabled reductions output, for coherence
with XSLT output.
* src/print_graph.c (print_core): Minor stylistic change to States' output.
(print_actions): Swap order of output for reductions and transitions.
* tests/local.at (AT_BISON_CHECK_XML): Ignore differences in order.
* tests/output.at: Adjust to changes in DOT internals.
