(Bison) Variants are extremely picky, which makes them both
annoying (lots of micro-details must be taken care of) and
precious (all the micro-details must be taken care of, in particular
object lifetime).
So (i) each time a semantic value is stored, it must be stored in a
place that exists, and (ii) each time a semantic value is discarded,
its place must have been emptied.
Example of (i)
- new (&yys.value ()) value_type (s->value ());
+ {]b4_variant_if([[
+ new (&yys.value ()) value_type ();
+ ]b4_symbol_variant([yy_accessing_symbol (s->yylrState)],
+ [yys.value ()], [copy], [s->value ()])], [[
+ new (&yys.value ()) value_type (s->value ());]])[
+ }
Example of (ii)
yyparser.yy_destroy_ ("Error: discarding",
- yytoken, &yylval]b4_locations_if([, &yylloc])[);
+ yytoken, &yylval]b4_locations_if([, &yylloc])[);]b4_variant_if([[
+ // Value type destructor.
+ ]b4_symbol_variant([[YYTRANSLATE (this->yychar)]], [[yylval]], [[template destroy]])])[
this->yychar = ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(empty, id)[;
However, in some places we must not be "pure". In particular:
glr_stack_item (const glr_stack_item& other) YY_NOEXCEPT YY_NOTHROW
: is_state_ (other.is_state_)
{
std::memcpy (raw_, other.raw_, union_size);
}
still must use memcpy, because the constructor would change pred, and
it must not. This constructor is used only when resizing the stack,
in which case pred (which is relative) must not be "adjusted".
The result works, but is messy. Its verbosity comes from at least two
factors:
- we don't have support for complete symbols (binding kind, value and
location), and we should at least try to have it. That simplified
lalr1.cc a lot.
- I have not tried to be smart and use 'move' when possible. As a
consequence many places have 'copy' and then 'destroy'. That kind
of clean up can be done once everything appears to be solid.
* data/skeletons/glr2.cc: Be more rigorous in object lifetime.
In particular, don't forget to discard the lookahead when we're done
with it.
Call variant routines where needed.
Deal with plenty of details.
(b4_call_merger): Add support for variants.
Use references in mergers, rather than pointers.
* examples/c++/glr/c++-types.yy: Exercise variants.
* examples/c/glr/c++-types.y (node_print): New.
Use YY_LOCATION_PRINT instead of duplicating it.
And actually use it in the action instead of badly duplicating it.
(main): Add proper option support.
* examples/c/glr/c++-types.test: Adjust expectations on locations.
* examples/c++/glr/c++-types.yy: Fix bad iteration.
We always refer to the triplet "kind, value, location". All of them
are nouns, and we support api.value.type and api.location.type. On
this regard, "semantic_type" was a poor choice. Make it "value_type".
The test suite was not updated to use value_type, on purpose, to
enforce backward compatibility.
* data/skeletons/c++.m4, data/skeletons/glr.cc, data/skeletons/glr2.cc,
* data/skeletons/variant.hh, doc/bison.texi: Define value_type rather
than semantic_type.
Add a backward compatibility typedef.
* examples/c++/glr/c++-types.yy: Migrate.
Currently we are using pointers. The whole point of
glr2.cc (vs. glr.cc) is precisely to allow genuine C++ objects to be
semantic values. Let's make that work.
* data/skeletons/glr2.cc (glr_state::glr_state): Be sure to initialize
yysval.
(glr_state): Add copy-ctor, assignment and dtor.
(glr_state::copyFrom): Be sure to initialize the destination if it was
not.
(glr_state::~glr_state): Destroy the semantic value.
* examples/c++/glr/ast.hh: Rewrite so that we use genuine objects,
rather than a traditional OOP hierarchy that requires to deal with
pointers.
With help from Bruno Belanyi <bruno.belanyi@epita.fr>.
* examples/c++/glr/c++-types.yy: Remove memory management.
Use true objects.
(main): Don't reach yydebug directly.
* examples/c++/glr/local.mk: We need C++11.
From a debugger, it is easier to pass a file name than working on
stdin.
* examples/c++/glr/c++-types.yy: Reduce scopes.
Avoid YYSTYPE/YYLTYPE: use the C++ types.
(input, process): New.
(main): Use them.
ast.hh:24:7: error: 'Node' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit [-Werror,-Wweak-vtables]
class Node
^
ast.hh:57:7: error: 'Nterm' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit [-Werror,-Wweak-vtables]
class Nterm : public Node
^
ast.hh:102:7: error: 'Term' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit [-Werror,-Wweak-vtables]
class Term : public Node
^
* examples/c++/glr/ast.hh: Define the destructors out of the class
definition.
This does not change anything, it is still in the header, but that
does pacify clang.
Currently the example really looks like C. Instead of a union of
structs to implement the AST, use a hierarchy. It would be nice to
feature a C++17 version with std variants.
* examples/c++/glr/c++-types.yy (Node, free_node, new_nterm)
(new_term): Move into...
* examples/c++/glr/ast.hh: here, a proper C++ hierarchy.
A glr_state keeps tracks of its predecessor using an offset relative
to itself (i.e., pointer subtraction). Unfortunately we sometimes
have to compute offsets for pointers that live in different
containers, in particular in yyfillin. In that case there is no
reason for the distance between the two objects to be a multiple of
the object size (0x40 on my machine), and the resulting ptrdiff_t may
be "wrong", i.e., it does allow to recover one from the other. We
cannot use "typed" pointer arithmetics here, the Euclidean division
has it wrong. So use "plain" char* pointers.
Fixes 718 (Duplicate representation of merged trees: glr2.cc) and
examples/c++/glr/c++-types.
Still XFAIL:
712: Improper handling of embedded actions and dollar(-N) in GLR parsers: glr2.cc
730: Incorrectly initialized location for empty right-hand side in GLR: glr2.cc
748: Incorrect lookahead during nondeterministic GLR: glr2.cc
* data/skeletons/glr2.cc (glr_state::as_pointer_): New.
(glr_state::pred): Use it.
* examples/c++/glr/c++-types.test: The test passes.
* tests/glr-regression.at (Duplicate representation of merged trees:
glr2.cc): Passes.
Currently this example crashes on input such as "T (x) + y;".
The same example with glr.c works properly.
* examples/c++/glr/Makefile, examples/c++/glr/README.md,
* examples/c++/glr/c++-types.test, examples/c++/glr/c++-types.yy,
* examples/c++/glr/local.mk, examples/c++/local.mk: New.
Based on examples/c/glr/c++-types.y.
Appearing on IRIX with gcc -mabi=n32.
Reported by Bruno Haible.
https://lists.gnu.org/r/bug-bison/2020-05/msg00039.html
* examples/c++/variant-11.yy, examples/c/bistromathic/parse.y: Don't
give chars to isdigit, cast them to unsigned char before.
* src/complain.c: Use c_isdigit.
* src/fixits.c (fixits_run): Avoid casts.
* src/lalr.c (goto_print): Use %zu for a size_t.
* doc/bison.texi (C++ Parser Context): New.
* data/skeletons/lalr1.cc (parser::yysymbol_name): Rename as...
(parser::symbol_name): this.
(A Complete C++ Example): Promote LAC, now that we have it.
Promote parse.error detailed over verbose.
* examples/c++/calc++/calc++.test, tests/local.at: Adjust.
This patch contains more fixes to prefer signed to unsigned
integer types, as modern tools like 'gcc -fsanitize=undefined'
can check for signed integer overflow but not unsigned overflow.
* NEWS: Document the API change.
* boostrap.conf (gnulib_modules): Add intprops.
* data/skeletons/glr.c: Include stddef.h and stdint.h,
since this skeleton can assume C99 or later.
(YYSIZEMAX): Now signed, and the minimum of SIZE_MAX and PTRDIFF_MAX.
(yybool) [!__cplusplus]: Now signed (which is how bool behaves).
(YYTRANSLATE): Avoid use of unsigned, and make the macro
safe even for values greater than UINT_MAX.
(yytnamerr, struct yyGLRState, struct yyGLRStateSet, struct yyGLRStack)
(yyaddDeferredAction, yyinitStateSet, yyinitGLRStack)
(yyexpandGLRStack, yymarkStackDeleted, yyremoveDeletes)
(yyglrShift, yyglrShiftDefer, yy_reduce_print, yydoAction)
(yyglrReduce, yysplitStack, yyreportTree, yycompressStack)
(yyprocessOneStack, yyreportSyntaxError, yyrecoverSyntaxError)
(yyparse, yy_yypstack, yypstack, yypdumpstack):
* tests/input.at (Torturing the Scanner):
Prefer ptrdiff_t to size_t.
* data/skeletons/c++.m4 (b4_yytranslate_define):
* src/AnnotationList.c (AnnotationList__computePredecessorAnnotations):
* src/AnnotationList.h (AnnotationIndex):
* src/InadequacyList.h (InadequacyListNodeCount):
* src/closure.c (closure_new):
* src/complain.c (error_message, complains, complain_indent)
(complain_args, duplicate_directive, duplicate_rule_directive):
* src/gram.c (nritems, ritem_print, grammar_dump):
* src/ielr.c (ielr_compute_ritem_sees_lookahead_set)
(ielr_item_has_lookahead, ielr_compute_annotation_lists)
(ielr_compute_lookaheads):
* src/location.c (columns, boundary_print, location_print):
* src/muscle-tab.c (muscle_percent_define_insert)
(muscle_percent_define_check_values):
* src/output.c (prepare_rules, prepare_actions):
* src/parse-gram.y (id, handle_require):
* src/reader.c (record_merge_function_type, packgram):
* src/reduce.c (nuseless_productions, nuseless_nonterminals)
(inaccessable_symbols):
* src/relation.c (relation_print):
* src/scan-code.l (variant, variant_table_size, variant_count)
(variant_add, get_at_spec, show_sub_message, show_sub_messages)
(parse_ref):
* src/scan-gram.l (<SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>)
(scan_integer, convert_ucn_to_byte, handle_syncline):
* src/scan-skel.l (at_complain):
* src/symtab.c (complain_symbol_redeclared)
(complain_semantic_type_redeclared, complain_class_redeclared)
(symbol_class_set, complain_user_token_number_redeclared):
* src/tables.c (conflict_tos, conflrow, conflict_table)
(conflict_list, save_row, pack_vector):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Prefer signed to unsigned integer.
* data/skeletons/lalr1.cc (yy_lac_check_):
* tests/actions.at (_AT_CHECK_PRINTER_AND_DESTRUCTOR):
* tests/local.at (AT_YYLEX_DEFINE(c)):
Omit now-unnecessary casts.
* data/skeletons/location.cc (b4_location_define):
* doc/bison.texi (Mfcalc Lexer, C++ position, C++ location):
Prefer int to unsigned for line and column numbers.
Change example to abort explicitly on memory exhaustion,
and fix an off-by-one bug that led to undefined behavior.
* data/skeletons/stack.hh (stack::operator[]):
Also allow ptrdiff_t indexes.
(stack::pop, slice::slice, slice::operator[]):
Index arg is now ptrdiff_t, not int.
(stack::ssize): New method.
(slice::range_): Now ptrdiff_t, not int.
* data/skeletons/yacc.c (b4_state_num_type): Remove.
All uses replaced by b4_int_type.
(YY_CONVERT_INT_BEGIN, YY_CONVERT_INT_END): New macros.
(yylac, yyparse): Use them around conversions that -Wconversion
would give false alarms about. Omit unnecessary casts.
(yy_stack_print): Use int rather than unsigned, and omit
a cast that doesn’t seem to be needed here any more.
* examples/c++/variant.yy (yylex):
* examples/c++/variant-11.yy (yylex):
Omit no-longer-needed conversions to unsigned.
* src/InadequacyList.c (InadequacyList__new_conflict):
Don’t assume *node_count is unsigned.
* src/output.c (muscle_insert_unsigned_table):
Remove; no longer used.
Commit 112ccb5ed7 moved the skeletons
from dist_pkgdata_DATA to dist_skeletons_DATA, hence broke the dependencies.
* Makefile.am (dependencies): New.
Use it where appropriate.
Convert some of the READMEs to Markdown, which is now more common, and
nicely displayed in some git hosting services.
Add missing READMEs and Makefiles. Generate XML, HTML and Dot files. Be
sure to ship the test files. Complete CLEANFILES to remove all generated
files.
* examples/calc++: Move into...
* examples/c++: here.
* examples/mfcalc, examples/rpcalc: Move into...
* examples/c: here.
* examples/README.md, examples/c++/calc++/Makefile, examples/c/local.mk,
* examples/c/mfcalc/Makefile, examples/c/rpcalc/Makefile,
* examples/d/README.md, examples/java/README.md:
New files.
* examples/test (medir): Be robust to deeper directory nesting.
Also, make sure that `make dist` generates a correct tarball even if
the C++ compiler does not work.
Reported by Nelson H. F. Beebe.
* m4/cxx.m4 (BISON_CXX_WORKS): Define to true/false instead of
true/exit 77. The latter is too dangerous to use (it directly quits).
(ENABLE_CXX): New name for the Automake conditional, for consistency
with ENABLE_CXX11 etc.
* tests/local.at (AT_COMPILE, AT_COMPILE_CXX): Adjust to the new
semantics of BISON_CXX_WORKS.
* examples/c++/local.mk: Skip the variant test if C++ does not work.
* examples/calc++/local.mk: Likewise.
On some systems (x86_64-pc-solaris2.11), with Developer Studio 12.5's
CC, we get:
".../include/CC/Cstd/vector.cc", line 127: Error: Cannot assign const yy::parser::stack_symbol_type to yy::parser::stack_symbol_type without "yy::parser::stack_symbol_type::operator=(const yy::parser::stack_symbol_type&)";.
".../include/CC/Cstd/vector", line 475: Where: While instantiating "std::vector<yy::parser::stack_symbol_type>::__insert_aux(yy::parser::stack_symbol_type*, const yy::parser::stack_symbol_type&)".
".../include/CC/Cstd/vector", line 475: Where: Instantiated from non-template code.
1 Error(s) detected.
Don't expect __cplusplus to be always defined. If it's not, consider
this is C++98.
Reported by Nelson H. F. Beebe.
* data/c++.m4, data/lalr1.cc, examples/c++/variant.yy, tests/local.at,
* tests/testsuite.h:
An undefined __cplusplus means pre C++11.
The CI is using Flex 2.5.35. And ICC is too picky for it. Let's stop
making these warnings errors. I wish I could disable them in the
source files using the ICC version and the Flex version, but ICC's
pragma support is unclear, and I'm tired of fighting it.
* configure.ac (FLEX_SCANNER_CXXFLAGS): Make warnings warnings.
* examples/c++/local.mk: Comment changes.
Suggested by Victor Khomenko.
http://lists.gnu.org/archive/html/bug-bison/2018-08/msg00037.html
* doc/bison.texi (A Simple C++ Example): New.
* examples/c++/local.mk, examples/c++/simple.test: New.
Extract, check, and install this new example.
* examples/local.mk: Adjust.
* examples/test: Adjust to the case where the dirname differs
from the test name.
