[PATCH 3/5] c++: improvements on symbol kinds

[Akim Demaille]

Instead of

    /// (Internal) symbol kind.
    enum symbol_kind_type
    {
      YYNTOKENS = 5, ///< Number of tokens.
      YYSYMBOL_YYEMPTY = -2,
      YYSYMBOL_YYEOF = 0,                      // END_OF_FILE
      YYSYMBOL_YYERROR = 1,                    // error
      YYSYMBOL_YYUNDEF = 2,                    // $undefined
      YYSYMBOL_TEXT = 3,                       // TEXT
      YYSYMBOL_NUMBER = 4,                     // NUMBER
      YYSYMBOL_YYACCEPT = 5,                   // $accept
      YYSYMBOL_result = 6,                     // result
      YYSYMBOL_list = 7,                       // list
      YYSYMBOL_item = 8                        // item
    };

generate

    /// Symbol kinds.
    struct symbol_kind
    {
      enum symbol_kind_type
      {
        YYNTOKENS = 5, ///< Number of tokens.
        S_YYEMPTY = -2,
        S_YYEOF = 0,                             // END_OF_FILE
        S_YYERROR = 1,                           // error
        S_YYUNDEF = 2,                           // $undefined
        S_TEXT = 3,                              // TEXT
        S_NUMBER = 4,                            // NUMBER
        S_YYACCEPT = 5,                          // $accept
        S_result = 6,                            // result
        S_list = 7,                              // list
        S_item = 8                               // item
      };
    };

* data/skeletons/c++.m4 (api.symbol.prefix): Define to S_.
Adjust all the uses.
(b4_public_types_declare): Nest the enum inside 'struct symbol_kind'.
* data/skeletons/glr.cc, data/skeletons/lalr1.cc,
* tests/headers.at, tests/local.at: Adjust.
---
 data/skeletons/c++.m4   | 36 +++++++++++++++++++++++-------------
 data/skeletons/glr.cc   |  8 ++++----
 data/skeletons/lalr1.cc | 16 +++++++++-------
 tests/headers.at        |  2 +-
 tests/local.at          |  2 +-
 5 files changed, 38 insertions(+), 26 deletions(-)

diff --git a/data/skeletons/c++.m4 b/data/skeletons/c++.m4
index eb273214..a0dbbd97 100644
--- a/data/skeletons/c++.m4
+++ b/data/skeletons/c++.m4
@@ -22,6 +22,8 @@ b4_percent_define_ifdef([[api.value.union.name]],
   [b4_complain_at(b4_percent_define_get_loc([[api.value.union.name]]),
                   [named %union is invalid in C++])])
 
+b4_percent_define_default([[api.symbol.prefix]], [[S_]])
+
 m4_include(b4_skeletonsdir/[c.m4])
 
 b4_percent_define_check_kind([api.namespace], [code], [deprecated])
@@ -187,12 +189,11 @@ m4_define([b4_token_enums],
 # to use a signed type, which matters for yytoken.
 m4_define([b4_declare_symbol_enum],
 [[enum symbol_kind_type
-    {
-      YYNTOKENS = ]b4_tokens_number[, ///< Number of tokens.
-      ]b4_symbol_kind([-2])[ = -2,
-]b4_symbol_foreach([    b4_symbol_enum])[
-    };
-]])
+      {
+        YYNTOKENS = ]b4_tokens_number[, ///< Number of tokens.
+        ]b4_symbol_kind([-2])[ = -2,
+]b4_symbol_foreach([      b4_symbol_enum])dnl
+[      };]])
 
 
 
@@ -252,7 +253,7 @@ m4_define([b4_public_types_declare],
       location_type location;])[
     };
 
-    /// Token numbers.
+    /// Token kinds.
     struct token
     {
       ]b4_token_enums[
@@ -261,8 +262,17 @@ m4_define([b4_public_types_declare],
     /// (External) token kind, as returned by yylex.
     typedef token::yytokentype token_type;
 
+    /// Symbol kinds.
+    struct symbol_kind
+    {
+      ]b4_declare_symbol_enum[
+    };
+
     /// (Internal) symbol kind.
-    ]b4_declare_symbol_enum[
+    typedef symbol_kind::symbol_kind_type symbol_kind_type;
+
+    /// The number of tokens.
+    static const symbol_kind_type YYNTOKENS = symbol_kind::YYNTOKENS;
 ]])
 
 
@@ -456,7 +466,7 @@ m4_define([b4_public_types_define],
   bool
   ]b4_parser_class[::basic_symbol<Base>::empty () const YY_NOEXCEPT
   {
-    return Base::type_get () == ]b4_symbol_prefix[YYEMPTY;
+    return Base::type_get () == symbol_kind::]b4_symbol_prefix[YYEMPTY;
   }
 
   template <typename Base>
@@ -472,7 +482,7 @@ m4_define([b4_public_types_define],
 
   // by_type.
   ]b4_inline([$1])b4_parser_class[::by_type::by_type ()
-    : type (]b4_symbol_prefix[YYEMPTY)
+    : type (symbol_kind::]b4_symbol_prefix[YYEMPTY)
   {}
 
 #if 201103L <= YY_CPLUSPLUS
@@ -494,7 +504,7 @@ m4_define([b4_public_types_define],
   ]b4_inline([$1])[void
   ]b4_parser_class[::by_type::clear ()
   {
-    type = ]b4_symbol_prefix[YYEMPTY;
+    type = symbol_kind::]b4_symbol_prefix[YYEMPTY;
   }
 
   ]b4_inline([$1])[void
@@ -540,11 +550,11 @@ m4_define([b4_yytranslate_define],
     const int user_token_number_max_ = ]b4_user_token_number_max[;
 
     if (t <= 0)
-      return ]b4_symbol_prefix[YYEOF;
+      return symbol_kind::]b4_symbol_prefix[YYEOF;
     else if (t <= user_token_number_max_)
       return YY_CAST (symbol_kind_type, translate_table[t]);
     else
-      return ]b4_symbol_prefix[YYUNDEF;]])[
+      return symbol_kind::]b4_symbol_prefix[YYUNDEF;]])[
   }
 ]])
 
diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index 3e7e56c3..a6d7471d 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -357,10 +357,10 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 ]b4_namespace_close[
 ]m4_define([b4_declare_symbol_enum],
 [[typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type 
yysymbol_kind_t;
-#define ]b4_symbol_prefix[YYEMPTY 
]b4_namespace_ref[::]b4_parser_class[::]b4_symbol_prefix[YYEMPTY
-#define ]b4_symbol_prefix[YYERROR 
]b4_namespace_ref[::]b4_parser_class[::]b4_symbol_prefix[YYERROR
-#define ]b4_symbol_prefix[YYEOF   
]b4_namespace_ref[::]b4_parser_class[::]b4_symbol_prefix[YYEOF
-#define ]b4_symbol_prefix[YYUNDEF 
]b4_namespace_ref[::]b4_parser_class[::]b4_symbol_prefix[YYUNDEF
+#define ]b4_symbol_prefix[YYEMPTY 
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
+#define ]b4_symbol_prefix[YYERROR 
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYERROR
+#define ]b4_symbol_prefix[YYEOF   
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
+#define ]b4_symbol_prefix[YYUNDEF 
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
 ]])[
 ]b4_percent_code_get([[provides]])[
 ]m4_popdef([b4_parse_param])dnl
diff --git a/data/skeletons/lalr1.cc b/data/skeletons/lalr1.cc
index e67ecc03..4387fbfc 100644
--- a/data/skeletons/lalr1.cc
+++ b/data/skeletons/lalr1.cc
@@ -700,7 +700,7 @@ b4_parse_error_case([verbose], [[
   ]b4_parser_class[::by_state::type_get () const YY_NOEXCEPT
   {
     if (state == empty_state)
-      return ]b4_symbol_prefix[YYEMPTY;
+      return symbol_kind::]b4_symbol_prefix[YYEMPTY;
     else
       return YY_CAST (symbol_kind_type, yystos_[+state]);
   }
@@ -725,7 +725,7 @@ b4_parse_error_case([verbose], [[
     b4_symbol_variant([that.type_get ()],
                       [value], [move], [YY_MOVE (that.value)])])[
     // that is emptied.
-    that.type = ]b4_symbol_prefix[YYEMPTY;
+    that.type = symbol_kind::]b4_symbol_prefix[YYEMPTY;
   }
 
 #if YY_CPLUSPLUS < 201103L
@@ -1089,7 +1089,7 @@ b4_dollar_popdef])[]dnl
            error, discard it.  */
 
         // Return failure if at end of input.
-        if (yyla.type_get () == ]b4_symbol_prefix[YYEOF)
+        if (yyla.type_get () == symbol_kind::]b4_symbol_prefix[YYEOF)
           YYABORT;
         else if (!yyla.empty ())
           {
@@ -1131,8 +1131,9 @@ b4_dollar_popdef])[]dnl
           yyn = yypact_[+yystack_[0].state];
           if (!yy_pact_value_is_default_ (yyn))
             {
-              yyn += ]b4_symbol_prefix[YYERROR;
-              if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == 
]b4_symbol_prefix[YYERROR)
+              yyn += symbol_kind::]b4_symbol_prefix[YYERROR;
+              if (0 <= yyn && yyn <= yylast_
+                  && yycheck_[yyn] == symbol_kind::]b4_symbol_prefix[YYERROR)
                 {
                   yyn = yytable_[yyn];
                   if (0 < yyn)
@@ -1244,7 +1245,8 @@ b4_dollar_popdef])[]dnl
     for (int yyx = 0; yyx < YYNTOKENS; ++yyx)
       {
         symbol_kind_type yysym = YY_CAST (symbol_kind_type, yyx);
-        if (yysym != ]b4_symbol_prefix[YYERROR && yysym != 
]b4_symbol_prefix[YYUNDEF
+        if (yysym != symbol_kind::]b4_symbol_prefix[YYERROR
+            && yysym != symbol_kind::]b4_symbol_prefix[YYUNDEF
             && yyparser_.yy_lac_check_ (yysym))
           {
             if (!yyarg)
@@ -1266,7 +1268,7 @@ b4_dollar_popdef])[]dnl
         int yychecklim = yylast_ - yyn + 1;
         int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
         for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
-          if (yycheck_[yyx + yyn] == yyx && yyx != ]b4_symbol_prefix[YYERROR
+          if (yycheck_[yyx + yyn] == yyx && yyx != 
symbol_kind::]b4_symbol_prefix[YYERROR
               && !yy_table_value_is_error_ (yytable_[yyx + yyn]))
             {
               if (!yyarg)
diff --git a/tests/headers.at b/tests/headers.at
index d746b8d7..f1cb7316 100644
--- a/tests/headers.at
+++ b/tests/headers.at
@@ -321,7 +321,7 @@ AT_PERL_CHECK([[-n -0777 -e '
       |YYChar
       |YYNTOKENS  # This is actual scoped in a C++ class.
       |YYPUSH_MORE(?:_DEFINED)?
-      |YYSYMBOL_(\w+)  # These guys are scoped.
+      |S_(YY(ACCEPT|EMPTY|EOF|ERROR|UNDEF))  # These guys are scoped.
       |YYUSE
       |YY_ATTRIBUTE(?:_PURE|_UNUSED)
       |YY(?:_REINTERPRET)?_CAST
diff --git a/tests/local.at b/tests/local.at
index 1b656a80..3e1cc1a8 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -756,7 +756,7 @@ void
   std::cerr << "syntax error";
   {
     symbol_kind_type la = ctx.token ();
-    if (la != YYSYMBOL_YYEMPTY)
+    if (la != symbol_kind::S_YYEMPTY)
       fprintf (stderr, " on token [%s]", yysymbol_name (la));
   }
   {
-- 
2.26.0