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api.value.type: implement proper support, check, and document

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* data/c.m4 (b4_symbol_type_register, b4_type_define_tag)
(b4_symbol_value_union, b4_value_type_setup_union)
(b4_value_type_setup_variant, b4_value_type_setup):
New.
(b4_value_type_define): Use it to set up properly the type.
Handle the various possible values of api.value.type.
* data/c++.m4 (b4_value_type_declare): Likewise.
* data/lalr1.cc (b4_value_type_setup_variant): Redefine.

* tests/types.at: New.
Exercise all the C/C++ skeletons with different types of
api.value.type values.
* tests/local.mk, tests/testsuite.at: Use it.

* doc/bison.texi (%define Summary): Document api.value.type.
* NEWS: Advertise it, together with api.token.constructor.
This commit is contained in:
Akim Demaille
2013-02-08 17:17:33 +01:00
parent dde95ca432
commit 6574576cfb
9 changed files with 463 additions and 25 deletions
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73
NEWS
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@@ -252,6 +252,77 @@ GNU Bison NEWS
use these prefixed token names, although the grammar itself still
uses the short names (as in the sample rule given above).
** Variable api.value.type
This new %define variable supersedes the #define macro YYSTYPE. The use
of YYSTYPE is discouraged. In particular, #defining YYSTYPE *and* either
using %union or %defining api.value.type results in undefined behavior.
Either define api.value.type, or use "%union":
%union
{
int ival;
char *sval;
}
%token <ival> INT "integer"
%token <sval> STRING "string"
%printer { fprintf (yyo, "%d", $$); } <ival>
%destructor { free ($$); } <sval>
/* In yylex(). */
yylval.ival = 42; return INT;
yylval.sval = "42"; return STRING;
The %define variable api.value.type supports several special values. The
value "union" means that the user provides genuine types, not union member
names such as "ival" and "sval" above.
%define api.value.type "union"
%token <int> INT "integer"
%token <char *> STRING "string"
%printer { fprintf (yyo, "%d", $$); } <int>
%destructor { free ($$); } <char *>
/* In yylex(). */
yylval.INT = 42; return INT;
yylval.STRING = "42"; return STRING;
The value "variant" is somewhat equivalent, but for C++ special provision
is made to allow classes to be used (more about this below).
%define api.value.type "variant"
%token <int> INT "integer"
%token <std::string> STRING "string"
Any other name is a user type to use. This is where YYSTYPE used to be
used.
%code requires
{
struct my_value
{
enum
{
is_int, is_string
} kind;
union
{
int ival;
char *sval;
} u;
};
}
%define api.value.type "struct my_value"
%token <u.ival> INT "integer"
%token <u.sval> STRING "string"
%printer { fprintf (yyo, "%d", $$); } <u.ival>
%destructor { free ($$); } <u.sval>
/* In yylex(). */
yylval.u.ival = 42; return INT;
yylval.u.sval = "42"; return STRING;
** Variable parse.error
This variable controls the verbosity of error messages. The use of the
@@ -2536,7 +2607,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
LocalWords: Wprecedence Rassoul Wempty Paolo Bonzini parser's Michiel loc
LocalWords: redeclaration sval fcaret reentrant XSLT xsl Wmaybe yyvsp Tedi
LocalWords: pragmas noreturn untyped Rozenman unexpanded Wojciech Polak
LocalWords: Alexandre MERCHANTABILITY
LocalWords: Alexandre MERCHANTABILITY yytype
Local Variables:
mode: outline

12
data/bison.m4
View File

@@ -361,6 +361,7 @@ b4_define_flag_if([yacc]) # Whether POSIX Yacc is emulated.
# Whether the symbol has an id.
# - id: string
# If has_id, the id. Guaranteed to be usable as a C identifier.
# Prefixed by api.token.prefix if defined.
# - tag: string.
# A representat of the symbol. Can be 'foo', 'foo.id', '"foo"' etc.
# - user_number: integer
@@ -371,9 +372,13 @@ b4_define_flag_if([yacc]) # Whether POSIX Yacc is emulated.
# The internalized number (used after yytranslate).
# - has_type: 0, 1
# Whether has a semantic value.
# - type_tag: string
# When api.value.type=union, the generated name for the union member.
# yytype_INT etc. for symbols that has_id, otherwise yytype_1 etc.
# - type
# If it has a semantic value, its type tag, or, if variant are used,
# its type.
# In the case of api.value.type=union, type is the real type (e.g. int).
# - has_printer: 0, 1
# - printer: string
# - printer_file: string
@@ -962,3 +967,10 @@ b4_percent_define_ifdef([api.prefix],
[['%s' and '%s' cannot be used together]],
[%name-prefix],
[%define api.prefix])])])
b4_percent_define_ifdef([api.value.type],
[m4_ifdef([b4_union_members],
[b4_complain_at(b4_percent_define_get_loc([api.value.type]),
[['%s' and '%s' cannot be used together]],
[%union],
[%define api.value.type])])])

15
data/c++.m4
View File

@@ -118,15 +118,16 @@ m4_define([b4_token_enums],
# ---------------------
# Declare semantic_type.
m4_define([b4_value_type_declare],
[b4_value_type_setup[]dnl
[ /// Symbol semantic values.
m4_ifdef([b4_union_members],
[ union semantic_type
]m4_bmatch(b4_percent_define_get([api.value.type]),
[^%union\|union$],
[[ union semantic_type
{
b4_user_union_members
};],
[m4_if(b4_tag_seen_flag, 0,
[[ typedef int semantic_type;]],
[[ typedef ]b4_api_PREFIX[STYPE semantic_type;]])])])
]b4_user_union_members[
};]],
[^$], [],
[[ typedef ]b4_percent_define_get([api.value.type])[ semantic_type;]])])
# b4_public_types_declare

117
data/c.m4
View File

@@ -492,28 +492,127 @@ b4_locations_if([, yylocationp])[]b4_user_args[);
}]dnl
])
## ---------------- ##
## api.value.type. ##
## ---------------- ##
# ---------------------- #
# api.value.type=union. #
# ---------------------- #
# b4_symbol_type_register(SYMBOL-NUM)
# -----------------------------------
# Symbol SYMBOL-NUM has a type (for variant) instead of a type-tag.
# Extend the definition of %union's body with a field of that type,
# and extend the symbol's "type" field to point to the field name,
# instead of the type name.
m4_define([b4_symbol_type_register],
[m4_define([b4_symbol($1, type_tag)],
[b4_symbol_if([$1], [has_id],
[b4_symbol([$1], [id])],
[yytype_[]b4_symbol([$1], [number])])])dnl
m4_append([b4_user_union_members],
m4_expand([
b4_symbol_tag_comment([$1])dnl
b4_symbol([$1], [type]) b4_symbol([$1], [type_tag]);]))
])
# b4_type_define_tag(SYMBOL1-NUM, ...)
# ------------------------------------
# For the batch of symbols SYMBOL1-NUM... (which all have the same
# type), enhance the %union definition for each of them, and set
# there "type" field to the field tag name, instead of the type name.
m4_define([b4_type_define_tag],
[b4_symbol_if([$1], [has_type],
[m4_map([b4_symbol_type_register], [$@])])
])
# b4_symbol_value_union(VAL, [TYPE])
# ----------------------------------
# Same of b4_symbol_value, but when api.value.type=union.
m4_define([b4_symbol_value_union],
[m4_ifval([$2],
[(*($2*)(&$1))],
[$1])])
])
# b4_value_type_setup_union
# -------------------------
# Setup support for api.value.type=union. Symbols are defined with a
# type instead of a union member name: build the corresponding union,
# and give the symbols their tag.
m4_define([b4_value_type_setup_union],
[m4_define([b4_union_members])
b4_type_foreach([b4_type_define_tag])
m4_copy_force([b4_symbol_value_union], [b4_symbol_value])
])
# ---------------- #
# api.value.type. #
# ---------------- #
# b4_value_type_setup_variant
# ---------------------------
# Setup support for api.value.type=variant. By default, fail, specialized
# by other skeletons.
m4_define([b4_value_type_setup_variant],
[b4_complain_at(b4_percent_define_get_loc([api.value.type]),
[['%s' does not support '%s']],
[b4_skeleton],
[%define api.value.type variant])])
# b4_value_type_setup
# -------------------
# Check if api.value.type is properly defined, and possibly prepare
# its use.
m4_define([b4_value_type_setup],
[b4_percent_define_default([[api.value.type]],
[m4_ifdef([b4_union_members], [%union],
[m4_if(b4_tag_seen_flag, 0, [int],
[])])])dnl
m4_case(b4_percent_define_get([api.value.type]),
[union], [b4_value_type_setup_union],
[variant], [b4_value_type_setup_variant])])
## -------------- ##
## Declarations. ##
## -------------- ##
# b4_value_type_define
# --------------------
m4_define([b4_value_type_define],
[[/* Value type. */
#if ! defined ]b4_api_PREFIX[STYPE && ! defined ]b4_api_PREFIX[STYPE_IS_DECLARED
]m4_ifdef([b4_union_members],
[[typedef union ]b4_union_name[ ]b4_api_PREFIX[STYPE;
[b4_value_type_setup[]dnl
/* Value type. */
m4_bmatch(b4_percent_define_get([api.value.type]),
[^%?union$],
[[#if ! defined ]b4_api_PREFIX[STYPE && ! defined ]b4_api_PREFIX[STYPE_IS_DECLARED
typedef union ]b4_union_name[ ]b4_api_PREFIX[STYPE;
union ]b4_union_name[
{
]b4_user_union_members[
};
# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1]],
[m4_if(b4_tag_seen_flag, 0,
[[typedef int ]b4_api_PREFIX[STYPE;
# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1]])])[
# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1
# define ]b4_api_PREFIX[STYPE_IS_DECLARED 1
#endif
]])
]],
[^$], [],
[[#if ! defined ]b4_api_PREFIX[STYPE && ! defined ]b4_api_PREFIX[STYPE_IS_DECLARED
typedef ]b4_percent_define_get([api.value.type])[ ]b4_api_PREFIX[STYPE;
# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1
# define ]b4_api_PREFIX[STYPE_IS_DECLARED 1
#endif
]])])
# b4_location_type_define

8
data/lalr1.cc
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@@ -17,6 +17,8 @@
m4_include(b4_pkgdatadir/[c++.m4])
# api.value.type=variant is valid.
m4_define([b4_value_type_setup_variant])
# b4_integral_parser_table_declare(TABLE-NAME, CONTENT, COMMENT)
# --------------------------------------------------------------
@@ -42,9 +44,11 @@ m4_define([b4_integral_parser_table_define],
# b4_symbol_value_template(VAL, [TYPE])
# -------------------------------------
# Same as b4_symbol_value, but used in a template method. It makes
# a difference when using variants.
# a difference when using variants. Note that b4_value_type_setup_union
# overrides b4_symbol_value, so we must override it again.
m4_copy([b4_symbol_value], [b4_symbol_value_template])
m4_append([b4_value_type_setup_union],
[m4_copy_force([b4_symbol_value_union], [b4_symbol_value_template])])
# b4_lhs_value([TYPE])
# --------------------

82
doc/bison.texi
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@@ -5586,6 +5586,7 @@ Summary,,%skeleton}).
Unaccepted @var{variable}s produce an error.
Some of the accepted @var{variable}s are described below.
@c ================================================== api.namespace
@deffn Directive {%define api.namespace} @{@var{namespace}@}
@itemize
@item Languages(s): C++
@@ -5812,14 +5813,89 @@ introduced in Bison 2.8
@deffn Directive {%define api.value.type} @var{type}
@itemize @bullet
@item Language(s):
C++
all
@item Purpose:
Request variant-based semantic values.
The type for semantic values.
@item Accepted Values:
@table @asis
@item @code{""}
This grammar has no semantic value at all. This is not properly supported
yet.
@item @code{%union} (C, C++)
The type is defined thanks to the @code{%union} directive. You don't have
to define @code{api.value.type} in that case, using @code{%union} suffices.
@xref{Union Decl, ,The Collection of Value Types}.
For instance:
@example
%define api.value.type "%union"
%union
@{
int ival;
char *sval;
@}
%token <ival> INT "integer"
%token <sval> STR "string"
@end example
@item @code{union} (C, C++)
The symbols are defined with type names, from which Bison will generate a
@code{union}. For instance:
@example
%define api.value.type "union"
%token <int> INT "integer"
%token <char *> STR "string"
@end example
This feature needs user feedback to stabilize. Note that most C++ objects
cannot be stored in a @code{union}.
@item @code{variant} (C++)
This is similar to @code{union}, but special storage techniques are used to
allow any kind of C++ object to be used. For instance:
@example
%define api.value.type "variant"
%token <int> INT "integer"
%token <std::string> STR "string"
@end example
This feature needs user feedback to stabilize.
@xref{C++ Variants}.
@item any other identifier
Use this name as semantic value.
@example
%code requires
@{
struct my_value
@{
enum
@{
is_int, is_str
@} kind;
union
@{
int ival;
char *sval;
@} u;
@};
@}
%define api.value.type "struct my_value"
%token <u.ival> INT "integer"
%token <u.sval> STR "string"
@end example
@end table
@item Default Value:
FIXME:
@itemize @minus
@item
@code{%union} if @code{%union} is used, otherwise @dots{}
@item
@code{int} if type tags are used (i.e., @samp{%token <@var{type}>@dots{}} or
@samp{%token <@var{type}>@dots{}} is used), otherwise @dots{}
@item
@code{""}
@end itemize
@item History:
introduced in Bison 2.8. Was introduced for Java only in 2.3b as
@code{stype}.

3
tests/local.mk
View File

@@ -63,7 +63,8 @@ TESTSUITE_AT = \
tests/sets.at \
tests/skeletons.at \
tests/synclines.at \
tests/torture.at
tests/torture.at \
tests/types.at
TESTSUITE = $(top_srcdir)/tests/testsuite

7
tests/testsuite.at
View File

@@ -35,6 +35,9 @@ m4_include([sets.at])
# Testing grammar reduction.
m4_include([reduce.at])
# Testing conflicts detection and resolution.
m4_include([conflicts.at])
# Testing that #lines are correct.
m4_include([synclines.at])
@@ -44,8 +47,8 @@ m4_include([headers.at])
# Testing that user actions are properly performed.
m4_include([actions.at])
# Testing conflicts detection and resolution.
m4_include([conflicts.at])
# Testing semantic types support.
m4_include([types.at])
# Fulling testing (compilation and execution of the parser) on calc.
m4_include([calc.at])

171
tests/types.at Normal file
View File

@@ -0,0 +1,171 @@
# Value type. -*- Autotest -*-
# Copyright (C) 2013 Free Software Foundation, Inc.
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
AT_BANNER([[Value type tests.]])
## ----------------------------------- ##
## %union vs. %define api.value.type. ##
## ----------------------------------- ##
AT_SETUP([[%union vs. %define api.value.type]])
AT_DATA([[input.y]],
[[%union { int ival; }
%define api.value.type "%union"
%%
exp: %empty;
]])
AT_BISON_CHECK([[input.y]], [[1]], [[]],
[[input.y:2.9-22: error: '%union' and '%define api.value.type' cannot be used together
]])
AT_CLEANUP
## ---------------- ##
## api.value.type. ##
## ---------------- ##
# AT_TEST($1: BISON-DIRECTIVES,
# $2: MORE-BISON-DIRECTIVES,
# $3: PARSER-ACTION,
# $4: INPUT, $5: SCANNER-ACTION,
# $6: RESULT)
# --------------------------------------
# Compile the grammar and check the expected result.
# BISON-DIRECTIVES are passed to AT_SETUP, contrary to MORE-BISON-DIRECTIVES.
m4_pushdef([AT_TEST],
[
AT_SETUP([$1])
AT_KEYWORDS([api.value.type])
AT_BISON_OPTION_PUSHDEFS([$1 $2])
AT_DATA_GRAMMAR([test.y],
[[%debug
%code
{
# include <stdio.h>
# include <stdlib.h>
]AT_YYERROR_DECLARE[
]AT_YYLEX_DECLARE[
}
]$1[
]$2[
%%
start: $3;
%%
]AT_YYERROR_DEFINE[
]AT_YYLEX_DEFINE([$4], [$5])[
]AT_MAIN_DEFINE[
]])
AT_FULL_COMPILE([[test]])
AT_PARSER_CHECK([./test], 0, [$6
], [stderr])
AT_BISON_OPTION_POPDEFS
AT_CLEANUP
])
m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc]],
[# A built-in type.
AT_TEST([%skeleton "]b4_skel["
%define api.value.type double],
[],
['1' '2' { printf ("%2.1f\n", $1 + $2); }],
["12"],
[AT_VAL = (res - '0') / 10.0],
[0.3])
# A user defined struct.
AT_TEST([%skeleton "]b4_skel["
%define api.value.type "struct foo"],
[%code requires { struct foo { float fval; int ival; }; }],
['1' '2'
{ printf ("%d %2.1f\n", $1.ival + $2.ival, $1.fval + $2.fval); }],
["12"],
[AT_VAL.ival = (res - '0') * 10;
AT_VAL.fval = (res - '0') / 10.f],
[30 0.3])
# A user defined union.
AT_TEST([%skeleton "]b4_skel["
%define api.value.type "union foo"],
[%code requires { union foo { float fval; int ival; }; }],
['1' '2' { printf ("%d %2.1f\n", $1.ival, $2.fval); }],
["12"],
[if (res == '1')
AT_VAL.ival = 10;
else
AT_VAL.fval = .2f],
[10 0.2])
# A %union.
AT_TEST([%skeleton "]b4_skel["
%union { float fval; int ival; };],
[%token <ival> '1';
%token <fval> '2';],
['1' '2' { printf ("%d %2.1f\n", $1, $2); }],
["12"],
[if (res == '1')
AT_VAL.ival = 10;
else
AT_VAL.fval = 0.2f],
[10 0.2])
# A Bison-defined union.
# The tokens names are not available directly in C++, we use their
# user number to keep it simple between C and C++.
AT_TEST([%skeleton "]b4_skel["
%define api.value.type union],
[%token <int> ONE 101;
%token <float> TWO 102 THREE 103;
%printer { ]AT_SKEL_CC_IF([[yyoutput << $$]],
[[fprintf (yyo, "%d", $$)]])[; } <int>
%printer { ]AT_SKEL_CC_IF([[yyoutput << $$]],
[[fprintf (yyo, "%f", $$)]])[; } <float>
],
[ONE TWO THREE { printf ("%d %2.1f %2.1f\n", $1, $2, $3); }],
[{ 101, 102, 103, EOF }],
[if (res == 101)
AT_VAL.ONE = 10;
else if (res == 102)
AT_VAL.TWO = .2f;
else if (res == 103)
AT_VAL.THREE = 3.3f],
[10 0.2 3.3])
# A Bison-defined variant, for lalr1.cc only.
m4_if(b4_skel, [lalr1.cc], [
AT_TEST([%skeleton "]b4_skel["
%define api.value.type variant],
[%token <int> '1';
%token <std::string> '2';],
['1' '2' { std::cout << $1 << ", " << $2 << std::endl; }],
["12"],
[if (res == '1')
AT_VAL.build(10);
else
AT_VAL.build<std::string>("two");],
[10, two])])
])
m4_popdef([AT_TEST])