Reported by Jot Dot.
https://lists.gnu.org/r/help-bison/2020-12/msg00014.html
* data/skeletons/glr.c, data/skeletons/glr2.cc (b4_call_merger): Use
the symbol's slot, not its type.
* examples/c/glr/c++-types.y: Use explicit per-symbol typing together
with api.value.type=union.
(yylex): Use yytoken_kind_t.
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.
The complete symbol approach in yylex removes the need for the methods
semanticVal, startPos and endPos, which were used when the values were
reported separately.
* data/skeletons/lalr1.d: Here.
* doc/bison.texi: Remove sections about the three methods.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Remove the unused methods.
* tests/calc.at, tests/d.at, tests/scanner.at: Test it.
* data/skeletons/d.m4 (b4_public_types_declare): Here.
* data/skeletons/lalr1.d: Adjust.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y: Use it.
* tests/calc.at: Test it.
* examples/d/calc/calc.y (start, end): Replace by this...
(location): new member variable in the Lexer class.
Use it.
* tests/calc.at: Use the defined location variable.
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.
This avoids heap allocation and gives minimal costs for the
creation and destruction of the YYParser.Symbol struct if
the location tracking is active.
Suggested by H. S. Teoh.
* data/skeletons/lalr1.d: Here.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y: Adjust.
* tests/calc.at: Test it.
The complete symbol approach was deemed to be the right approach for Dlang.
Now, the user can return from yylex() an instance of YYParser.Symbol structure,
which binds together the TokenKind, the semantic value and the location. Before,
the last two were reported separately to the parser.
Only the user API is changed, Bisons's internal structure is kept the same.
* data/skeletons/d.m4 (struct YYParser.Symbol): New.
* data/skeletons/lalr1.d: Change the return value.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate it.
* tests/calc.at, tests/scanner.at: Test it.
Parser.Context class returns a const YYLocation, so Lexer's method
yyerror() needs to receive the location as a const parameter.
Internal error reporting flow is changed to be similar to that of
the other skeletons. Before, case YYERRLAB was calling yyerror()
with the result of yysyntax_error() as the string parameter. As the
custom error message lets the user decide if they want to use
yyerror() or not, this flow needed to be changed. Now, case YYERRLAB
calls yyreportSyntaxError(), that builds the error message using
yysyntaxErrorArguments(). Then yyreportSyntaxError() passes the
error message to the user defined syntax_error() in case of a custom
message, or to yyerror() otherwise.
In the tests in tests/calc.at, the order of the tokens needs to be
changed in order of precedence, so that the D program outputs the
expected tokens in the same order as the other parsers.
* data/skeletons/lalr1.d: Add the custom error message feature.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y: Adjust.
* tests/calc.at, tests/local.at: Test it.
In D's case, yyerrok() is a private method of the Parser class.
It can be called directly as `yyerrok()` from the grammar rules section.
* data/skeletons/lalr1.d: Add yyerrok().
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate yyerrok().
* tests/calc.at: Update D tests to use yyerrok().
examples/java/calc/Calc.java:1531: warning: [deprecation] Integer(String) in Integer has been deprecated
yylval = new Integer(st.sval);
^
* examples/java/calc/Calc.y, examples/java/simple/Calc.y,
* tests/calc.at, tests/scanner.at: Use Integer.parseInt.
Shamelessly stolen from Adrian Vogelsgesang's implementation in
lalr1.cc.
* data/skeletons/lalr1.java (yycdebugNnl, yyLacCheck, yyLacEstablish)
(yyLacDiscard, yylacStack, yylacEstablished): New.
(Context): Use it.
* examples/java/calc/Calc.y: Enable LAC.
* upstream/maint:
doc: fix typo
maint: post-release administrivia
version 3.7.3
build: don't link bison against libreadline
gnulib: update
glr.cc: fix: use symbol_name
build: fix a concurrent build issue in examples
This is something that has always bothered me: with pure parsers (and
they all should be) the user does not have an (easy) access to yynerrs
at the end of the parse. In the case of error recovery, that's the
only direct means to know if there were errors. The usual approach
being having the user maintain a counter incremented each time yyerror
is called.
So here, also capture yynerrs in the return value of the start-symbol
parsing functions.
* data/skeletons/yacc.c (yy_parse_impl_t): New.
(yy_parse_impl): Use it.
(b4_accept): Fill it.
* examples/c/lexcalc/parse.y, examples/c/lexcalc/scan.l: No longer
pass nerrs as lex- and parse-param, just use the resulting yynerrs.
bistromathic and reccalc both demonstrate %param.
After all, why not?
* src/reader.c (switching_token): Use symbol_id_get.
(check_start_symbols): Require that the start symbol is a token only
if it's the only one.
* examples/c/lexcalc/parse.y: Let NUM be a start symbol.
For each start symbol, generate a parsing function with a richer
return value than the usual of yyparse. Reserve a place for the
returned semantic value, in order to avoid having to pass a pointer as
argument to "return" that value. This also makes the call to the
parsing function independent of whether a given start-symbol is typed.
For instance, if the grammar file contains:
%type <int> expression
%start input expression
(so "input" is valueless) we get
typedef struct
{
int yystatus;
} yyparse_input_t;
yyparse_input_t yyparse_input (void);
typedef struct
{
int yyvalue;
int yystatus;
} yyparse_expression_t;
yyparse_expression_t yyparse_expression (void);
This commit also changes the implementation of the parser termination:
when there are multiple start symbols, it is the initial rules that
explicitly YYACCEPT. They do that after having exported the
start-symbol's value (if it is typed):
switch (yyn)
{
case 1: /* $accept: YY_EXPRESSION expression $end */
{ ((*yyvalue).TOK_expression) = (yyvsp[-1].TOK_expression); YYACCEPT; }
break;
case 2: /* $accept: YY_INPUT input $end */
{ YYACCEPT; }
break;
I have tried several ways to deal with termination, and this is the
one that appears the best one to me. It is also the most natural.
* src/scan-code.h, src/scan-code.l (obstack_for_actions): New.
* src/reader.c (grammar_rule_check_and_complete): Generate the actions
of the rules for each start symbol.
* data/skeletons/bison.m4 (b4_symbol_slot): New, with safer semantics
than type and type_tag.
* data/skeletons/yacc.c (b4_accept): New.
Generates the body of the action of the start rules.
(_b4_declare_sub_yyparse): For each start symbol define a dedicated
return type for its parsing function.
Adjust the declaration of its parsing function.
(_b4_define_sub_yyparse): Adjust the definition of the function.
* examples/c/lexcalc/parse.y: Check the case of valueless symbols.
* examples/c/lexcalc/lexcalc.test: Check start symbols.
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.
* data/skeletons/lalr1.d: Change the return value.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Adjust.
* tests/scanner.at: Adjust.
* tests/calc.at (_AT_DATA_CALC_Y(d)): New, extracted from...
(_AT_DATA_CALC_Y(c)): here.
The two grammars have been sufficiently different to be separated.
Still trying to be them together results in a maintenance burden. For
the same reason, instead of specifying the results for D and for the
rest, compute the expected results with D from the regular case.
Based on the test case 668 (cxx-type.at:437) "GLR: Merge conflicting
parses, pure, locations".
* examples/c/glr/Makefile, examples/c/glr/README.md,
* examples/c/glr/c++-types.test, examples/c/glr/c++-types.y,
* examples/c/glr/local.mk: New.
The name "defines" is incorrect, the generated file contains far more
than just #defines.
* src/getargs.h, src/getargs.c (-H, --header): New option.
With optional argument, just like --defines, --xml, etc.
(defines_flag): Rename as...
(header_flag): this.
Adjust dependencies.
* data/skeletons/bison.m4, data/skeletons/c.m4, data/skeletons/glr.c,
* data/skeletons/glr.cc, data/skeletons/glr2.cc, data/skeletons/lalr1.cc,
* data/skeletons/yacc.c:
Adjust.
* examples, doc/bison.texi: Adjust.
* tests/headers.at, tests/local.at, tests/output.at: Convert most
tests from using --defines to using --header.
Reported by Dennis Clarke.
https://lists.gnu.org/r/bug-bison/2020-08/msg00013.html
* examples/d/local.mk, examples/java/calc/local.mk,
* examples/java/simple/local.mk: Pass bison's options before its
argument, in case we're in POSIX mode.
Reported by Agency for Defense Development.
https://lists.gnu.org/r/bug-bison/2020-08/msg00008.html
On an empty such as
%token FOO
BAR
FOO 0
%%
input: %empty
we crash because when we find FOO 0, we decrement ntokens (since FOO
was discovered to be EOF, which is already known to be a token, so we
increment ntokens for it, and need to cancel this). This "works well"
when EOF is properly defined in one go, but here it is first defined
and later only assign token code 0. In the meanwhile BAR was given
the token number that we just decremented.
To fix this, assign symbol numbers after parsing, not during parsing,
so that we also saw all the explicit token codes. To maintain the
current numbers (I'd like to keep no difference in the output, not
just equivalence), we need to make sure the symbols are numbered in
the same order: that of appearance in the source file. So we need the
locations to be correct, which was almost the case, except for nterms
that appeared several times as LHS (i.e., several times as "foo:
..."). Fixing the use of location_of_lhs sufficed (it appears it was
intended for this use, but its implementation was unfinished: it was
always set to "false" only).
* src/symtab.c (symbol_location_as_lhs_set): Update location_of_lhs.
(symbol_code_set): Remove broken hack that decremented ntokens.
(symbol_class_set, dummy_symbol_get): Don't set number, ntokens and
nnterms.
(symbol_check_defined): Do it.
(symbols): Don't count nsyms here.
Actually, don't count nsyms at all: let it be done in...
* src/reader.c (check_and_convert_grammar): here. Define nsyms from
ntokens and nnterms after parsing.
* tests/input.at (EOF redeclared): New.
* examples/c/bistromathic/bistromathic.test: Adjust the traces: in
"%nterm <double> exp %% input: ...", exp used to be numbered before
input.
* examples/c/bistromathic/parse.y (user_context): We need the current
line.
(yyreport_syntax_error): Quote the guilty line, with squiggles.
* examples/c/bistromathic/bistromathic.test: Adjust.
Currently autocompletion on a line with errors leaks the error
messages. It can be useful to let the user know, but GNU Readline
does not provide us with an nice way to display the error. So we
actually break into the current line of the user.
So instead, do not show these errors.
* examples/c/bistromathic/parse.y (user_context): New.
Use %param to pass it to the parser and scanner.
Keep quiet when in computing autocompletion.
That quite defeats the whole point of locations... But anyway, we
should not see these messages at all.
* examples/c/bistromathic/parse.y (expected_tokens): Fix (useless)
location tracking.
