I have been hesitating a lot before doing it ---after all the user
must not use this kind, so what's the point of showing it in
yytoken_kind_t. And eventually I chose to play it safe with the
typing system and make it possible to use yytoken_kind_t for all the
tokens, even the "empty token".
* data/skeletons/c.m4: Give an id and a tag to YYEMPTY.
(b4_token_enums): Define YYEMPTY.
* data/skeletons/c++.m4 (b4_token_enums): Define YYEMPTY.
* data/skeletons/glr.c, data/skeletons/glr.cc, data/skeletons/yacc.c:
(YYEMPTY): Remove.
Use b4_symbol(-2, id) instead.
The user should think of yypcontext fields as accessible only via
yypcontext_* functions. So let's rename yyexpected_tokens to reflect
that.
Let's _not_ rename yyreport_syntax_error, as the user may define this
function, and is not allowed to access directly the fields of
yypcontext_t: she *must* use the "accessors". This is comparable to
the case of C++/Java where the user defines
parser::report_syntax_error, not parser::context::report_syntax_error.
* data/skeletons/glr.c, data/skeletons/yacc.c (yyexpected_tokens):
Rename as...
(yypcontext_expected_tokens): this.
Adjust dependencies.
The name "$end" is nice in the report, in particular it avoids that
pointed-rules (aka items) be too long. It also helps keeping them
"standard".
But it is bad in error messages, we should report "end of file" (or
maybe "end of input", this is debatable). So, unless the user already
defined the alias for the error token herself, make it "end of file".
It should even be translated if the user already translated some
tokens, so that there is now no strong reason to redefine the $end
token.
* src/output.c (prepare_symbol_names): Issue "end of file" instead of
"$end".
* data/skeletons/lalr1.java (yytnamerr_): Remove the renaming hack.
* build-aux/update-test: Accept files with names containing a "+",
such as c++.at.
* tests/actions.at, tests/c++.at, tests/conflicts.at,
* tests/glr-regression.at, tests/regression.at, tests/skeletons.at:
Adjust.
yy::parser features a parse() function, not a yyparse() one.
* data/skeletons/lalr1.cc (yyreport_syntax_error)
(context::yyexpected_tokens): Rename as...
(report_syntax_error, context::expected_tokens): these.
Currently EOF is handled in an adhoc way, with a #define YYEOF 0 in
the implementation file. As a result, the user has to define her own
EOF token if she wants to use it, which is a pity.
Give the $end token a visible kind name, YYEOF. Except that in C,
where enums are not scoped, we would have collisions between all the
definitions of YYEOFs in the header files, so in C, make it
<api.PREFIX>EOF.
* data/skeletons/c.m4 (YYEOF): Override its name to avoid collisions.
Unless the user already gave it a different name.
* data/skeletons/glr.c (YYEOF): Remove.
Use ]b4_symbol(0, [id])[ instead.
Add support for "pre_epilogue", for glr.cc.
* data/skeletons/glr.cc: Remove dead code (never emitted #undefs).
* data/skeletons/yacc.c
* src/parse-gram.c
* src/reader.c
* src/symtab.c
* tests/actions.at
* tests/input.at
* data/skeletons/bison.m4 (b4_symbol_token_kind): Give a definition to
$undefined.
(b4_token_visible_if): $undefined has an id.
* src/output.c (prepare_symbol_definitions): Stop lying: $undefined
_is_ a token.
* tests/input.at: Adjust.
There are people out there that do use YYERRCODE (the token kind of
the error token). See for instance
3812012bb7/unixODBC-2.3.2/Drivers/nn/yylex.c.
Currently, YYERRCODE is defined by yacc.c in an adhoc way as a #define
in the *.c file only. It belongs with the other token kinds.
YYERRCODE is not a nice name, it does not fit in our naming scheme.
YYERROR would be more logical, but it collides with the YYERROR macro.
Shall we keep the same name in all the skeletons? Besides, to avoid
collisions in C, we need to apply the api prefix: YYERRCODE is
actually <PREFIX>ERRCODE. This is not needed in the other languages.
* data/skeletons/bison.m4 (b4_symbol_token_kind): New.
Map the error token to "YYERRCODE".
* data/skeletons/yacc.c (YYERRCODE): Don't define it, it's handled by...
* src/output.c (prepare_symbol_definitions): this.
* tests/input.at (Redefining the error token): Check it.
* data/skeletons/bison.m4 (b4_symbol_kind): Dispatch on the UNDEF
token number rather than its name.
* data/skeletons/c++.m4, data/skeletons/c.m4, data/skeletons/java.m4:
Comment changes.
A forthcoming commit (tokens: properly define the "error" token kind)
revealed a problem in the C++ generated headers: they are not
self-contained. With this file:
%language "c++"
%define api.value.type variant
%code {
static int yylex (yy::parser::semantic_type *lvalp);
}
%token <int> X
%%
exp:
X { printf ("x\n"); }
;
%%
void
yy::parser::error (const std::string& m)
{
std::cerr << m << '\n';
}
static
int yylex (yy::parser::semantic_type *lvalp)
{
static int const input[] = {yy::parser::token::X, 0};
static int toknum = 0;
return input[toknum++];
}
int
main (int argc, char const* argv[])
{
yy::parser p;
return p.parse ();
}
the generated header fails to compile cleanly (foo.cc just #includes
the generated header):
$ clang++-mp-9.0 -c -Wundefined-func-template foo.cc
In file included from foo.cc:1:
bar.tab.hh:550:12: warning: instantiation of function 'yy::parser::basic_symbol<yy::parser::by_type>::basic_symbol' required here, but no definition is available
[-Wundefined-func-template]
struct symbol_type : basic_symbol<by_type>
^
bar.tab.hh:436:7: note: forward declaration of template entity is here
basic_symbol (basic_symbol&& that);
^
bar.tab.hh:550:12: note: add an explicit instantiation declaration to suppress this warning if 'yy::parser::basic_symbol<yy::parser::by_type>::basic_symbol' is explicitly instantiated
in another translation unit
struct symbol_type : basic_symbol<by_type>
^
1 warning generated.
* data/skeletons/c++.m4 (b4_public_types_define): Move the
implementation of the basic_symbol move-ctor to...
(b4_public_types_define): here, its declaration.
* tests/headers.at (Sane headers): Use a declared token so that the
corresponding token constructor is declared. Which triggers the
aforementioned issue.
That's one nice benefit from using enums.
* data/skeletons/lalr1.java (YYSYMBOL_YYEMPTY): No longer define it.
Use 'null' instead.
* examples/java/calc/Calc.y, tests/local.at: Adjust.
* data/skeletons/bison.m4, data/skeletons/c++.m4, data/skeletons/c.m4,
* data/skeletons/glr.cc, data/skeletons/lalr1.cc,
* data/skeletons/lalr1.d, data/skeletons/lalr1.java:
Refer to the "kind" of a symbol, not its "type", where appropriate.
* maint:
maint: post-release administrivia
version 3.5.4
examples: reccalc: really compile cleanly in C99
news: announce that Bison 3.6 drops YYERROR_VERBOSE
news: update for 3.5.4
style: fix spellos
typo: succesful -> successful
package: improve the readme
java: check and fix support for api.token.raw
java: style: prefer 'int[] foo' to 'int foo[]'
build: fix syntax-check issues
tests: recheck: work properly when the test suite was interrupted
doc: c++: promote api.token.raw
build: fix compatibility with old compilers
examples: reccalc: compile cleanly in C99
The first name is too long. We already have `yypstate`, so
`yypcontext` is ok. We are also migrating to using `*_t` for our
types.
* NEWS, data/skeletons/glr.c, data/skeletons/yacc.c, doc/bison.texi,
* examples/c/bistromathic/parse.y, src/parse-gram.y, tests/local.at:
(yyparse_context_t, yyparse_context_location, yyparse_context_token):
Rename as...
(yypcontext_t, yypcontext_location, yypcontext_token): these.
The Java enums are very different from the C model. As a consequence,
one cannot "build" an enum directly from an integer, we must retrieve
it. That's the purpose of the SymbolType.get class method.
* data/skeletons/java.m4 (b4_symbol_enum, b4_case_code_symbol)
(b4_declare_symbol_enum): New.
* data/skeletons/lalr1.java: Use SymbolType,
SymbolType.YYSYMBOL_YYEMPTY, etc.
* examples/java/calc/Calc.y, tests/local.at: Adjust.
* tests/local.at (AT_LANG_MATCH, AT_YYERROR_DECLARE(java))
(AT_YYERROR_DECLARE_EXTERN(java), AT_PARSER_CLASS): New.
(AT_MAIN_DEFINE(java)): Use AT_PARSER_CLASS.
* tests/scanner.at: Add a test for Java.
* data/skeletons/lalr1.java (yytranslate_): Cast the result.
* data/skeletons/d.m4 (b4_symbol_enum, b4_declare_symbol_enum): New.
* data/skeletons/lalr1.d: Use them.
Use SymbolType, SymbolType.YYSYMBOL_YYEMPTY etc. where appropriate.
(undef_token_, token_number_type, yy_error_token_): Remove.
Because of the insane current implementation of glr.cc, things are a
bit nasty. We will rename symbol_number_type as symbol_type_type
later, to keep this commit small.
* data/skeletons/c++.m4 (b4_declare_symbol_enum): New.
Also define YYNTOKENS to avoid type clashes when yyntokens_ was
actually defined in another enum.
Use it.
(symbol_number_type): Be an alias of symbol_type_type.
Use YYSYMBOL_YYEMPTY and the like.
Use symbol_number_type where appropriate.
(empty_symbol): Remove.
(yytranslate_): Use symbol_number_type, not token_number_type.
* data/skeletons/lalr1.cc: Use symbol_number_type where appropriate.
Adjust to the replacement of empty_symbol by YYSYMBOL_YYEMPTY.
(yy_error_token_, yy_undef_token_, yyeof_, yyntokens_): Remove.
Adjust dependencies.
* data/skeletons/glr.cc: Use symbol_number_type where appropriate.
Forward definitions of YYSYMBOL_YYEMPTY, etc. to glr.c.
* tests/headers.at: Accept YYNTOKENS and other YYSYMBOL_*.
* tests/local.at (AT_YYERROR_DEFINE(c++)): Use symbol_number_type.
Now that yacc.c and glr.c both know yysymbol_type_t, convert the
common routines.
* data/skeletons/c.m4 (yydestruct, yy_symbol_value_print)
(yy_symbol_print): Use yysymbol_type_t instead of int.
* data/skeletons/glr.c: Use yySymbol where appropriate.
* data/skeletons/yacc.c (YY_ACCESSING_SYMBOL): New wrapper around
yystos.
Use it.
* tests/local.at (yyreport_syntax_error): Use yysymbol_type_t where
appropriate.
Apply the same changes as in yacc.c. Now yySymbol and yysymbol_type_t
are aliases. We will remove the former later, to avoid cluttering
this commit.
* data/skeletons/glr.c: Use b4_declare_symbol_enum.
Use YYSYMBOL_YYEOF etc. where appropriate.
(YYUNDEFTOK, YYTERROR): Remove.
(YYTRANSLATE, yySymbol, yyexpected_tokens, yysyntax_error_arguments):
Adjust.
(yy_accessing_symbol): New.
Use it where appropriate.
This triggers warnings with several compilers. For instance ICC fills
the logs with pages and pages of
input.c(477): error: a value of type "int" cannot be used to initialize an entity of type "const yysymbol_type_t={yysymbol_type_t}"
0, 2, 2, 2, 2, 2, 2, 2, 2, 2,
^
input.c(477): error: a value of type "int" cannot be used to initialize an entity of type "const yysymbol_type_t={yysymbol_type_t}"
0, 2, 2, 2, 2, 2, 2, 2, 2, 2,
^
And so does G++9 when compiling yacc.c's (C) output
input.c:545:8: error: invalid conversion from 'int' to 'yysymbol_type_t' [-fpermissive]
545 | 0, 5, 9, 2, 2, 2, 2, 2, 2, 2,
| ^
| |
| int
input.c:545:15: error: invalid conversion from 'int' to 'yysymbol_type_t' [-fpermissive]
545 | 0, 5, 9, 2, 2, 2, 2, 2, 2, 2,
| ^
| |
| int
Clang++ is no exception
input.c:545:8: error: cannot initialize an array element of type 'const yysymbol_type_t' with an rvalue of type 'int'
0, 5, 9, 2, 2, 2, 2, 2, 2, 2,
^
input.c:545:15: error: cannot initialize an array element of type 'const yysymbol_type_t' with an rvalue of type 'int'
0, 5, 9, 2, 2, 2, 2, 2, 2, 2,
^
At some point we could use yysymbol_type_t's enumerators to define
yytranslate. Meanwhile...
* data/skeletons/yacc.c (yytranslate): Use the original integral type
to define it.
(YYTRANSLATE): Cast the result into yysymbol_type_t.
Currently we define enumerators only for symbols that have an
identifier. That rules out tokens such as '+', and nonterminals such
as foo-bar and foo.bar. As a consequence we are taking chances: the
compiler might compile yysymbol_type_t as too small an integral type
for some symbol codes.
* data/skeletons/bison.m4 (b4_symbol_sid): Forge a unique symbol
identifier for symbols that don't have an ID.
This is not only cleaner, it also protects us from mixing signed
values (YYEMPTY is #defined as -2) with unsigned types (the
yysymbol_type_t enum is typically compiled as a small unsigned).
For instance GCC 9:
input.c: In function 'yyparse':
input.c:1107:7: error: conversion to 'unsigned int' from 'int'
may change the sign of the result
[-Werror=sign-conversion]
1107 | yyn += yytoken;
| ^~
input.c:1107:10: error: conversion to 'int' from 'unsigned int'
may change the sign of the result
[-Werror=sign-conversion]
1107 | yyn += yytoken;
| ^~~~~~~
input.c:1108:47: error: comparison of integer expressions of
different signedness:
'yytype_int8' {aka 'const signed char'} and
'yysymbol_type_t' {aka 'enum yysymbol_type_t'}
[-Werror=sign-compare]
1108 | if (yyn < 0 || YYLAST < yyn || yycheck[yyn] != yytoken)
| ^~
input.c:702:25: error: operand of ?: changes signedness from 'int'
to 'unsigned int' due to unsignedness of
other operand [-Werror=sign-compare]
702 | #define YYEMPTY (-2)
| ^~~~
input.c:1220:33: note: in expansion of macro 'YYEMPTY'
1220 | yytoken = yychar == YYEMPTY ? YYEMPTY : YYTRANSLATE (yychar);
| ^~~~~~~
input.c:1220:41: error: unsigned conversion from 'int' to
'unsigned int' changes value
from '-2' to '4294967294'
[-Werror=sign-conversion]
1220 | yytoken = yychar == YYEMPTY ? YYEMPTY : YYTRANSLATE (yychar);
| ^
Eventually, it might be interesting to move away from -2 (which is the
only possible negative symbol number) and use the next available
number, to save bits. We could actually even simply use "0" and shift
the rest, which would allow to write "!yytoken" to mean really
"yytoken != YYEMPTY".
* data/skeletons/c.m4 (b4_declare_symbol_enum): Define YYSYMBOL_YYEMPTY.
* data/skeletons/yacc.c: Use it.
* src/parse-gram.y (yyreport_syntax_error): Use YYSYMBOL_YYEMPTY, not
YYEMPTY, when dealing with a symbol.
* tests/regression.at: Adjust.
Now that we have a proper type for internal symbol numbers, let's use
it. More code needs conversion, e.g., printers and destructors, but
they are shared with glr.c, which is not ready yet for this change.
It will also help us deal with warnings such as (GCC9 on GNU/Linux):
input.c: In function 'int yyparse()':
input.c:475:37: error: enumeral and non-enumeral type in conditional expression [-Werror=extra]
475 | (0 <= (YYX) && (YYX) <= YYMAXUTOK ? yytranslate[YYX] : YYSYMBOL_YYUNDEF)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
input.c:1024:17: note: in expansion of macro 'YYTRANSLATE'
1024 | yytoken = YYTRANSLATE (yychar);
| ^~~~~~~~~~~
* data/skeletons/yacc.c (yytranslate, yysymbol_name)
(yyparse_context_t, yyexpected_tokens, yypstate_expected_tokens)
(yysyntax_error_arguments):
Use yysymbol_type_t instead of int.
There's a number of advantage in exposing the symbol (internal)
numbers:
- custom error messages can use them to decide how to represent a
given symbol, or a set of symbols.
- we need something similar in uses of yyexpected_tokens. For
instance, currently, bistromathic's completion() reads:
int ntokens = expected_tokens (line, tokens, YYNTOKENS);
[...]
for (int i = 0; i < ntokens; ++i)
if (tokens[i] == YYTRANSLATE (TOK_VAR))
[...]
else if (tokens[i] == YYTRANSLATE (TOK_FUN))
[...]
else
[...]
- now that it's a compile-time expression, we can easily build static
tables, switch, etc.
- some users depended on the ability to get the token number from a
symbol to write test cases for their scanners. But Bison 3.5
removed the table this feature depended upon (a reverse
yytranslate). Now they can check against the actual symbol number,
without having pay (space and time) a conversion.
See https://lists.gnu.org/r/bug-bison/2020-01/msg00001.html, and
https://lists.gnu.org/archive/html/bug-bison/2020-03/msg00015.html.
- it helps us clearly separate the internal symbol numbers from the
external token numbers, whose difference is sometimes blurred in the
code when values coincide (e.g. "yychar = yytoken = YYEOF").
- it allows us to get rid of ugly macros with inconsistent names such
as YYUNDEFTOK and YYTERROR, and to group related definitions
together.
- similarly it provides a clean access to the $accept symbol (which
proves convenient in a current experimentation of mine with several
%start symbols).
Let's declare this type as a private type (in the *.c file, not
the *.h one). So it does not need to be influenced by the api prefix.
* data/skeletons/bison.m4 (b4_symbol_sid): New.
(b4_symbol): Use it.
* data/skeletons/c.m4 (b4_symbol_enum, b4_declare_symbol_enum): New.
* data/skeletons/yacc.c: Use b4_declare_symbol_enum.
(YYUNDEFTOK, YYTERROR): Remove.
Use the corresponding symbol enum instead.
