c++: provide yy::parser::symbol_type::name

* data/skeletons/c++.m4 (yy::parser::basic_symbol::name): New.
* data/skeletons/lalr1.cc (yy_print_): Use it.
* doc/bison.texi: Document.
* tests/c++.at: Check.

NEWS

@@ -8,6 +8,10 @@ GNU Bison NEWS
 
   In C++, yy::parser::symbol_name is now a public member, as was intended.
 
+** New features
+
+  In C++, yy::parser::symbol_type now has a public name() member function.
+
 * Noteworthy changes in release 3.6 (2020-05-08) [stable]
 
 ** Backward incompatible changes

data/skeletons/c++.m4

@@ -357,6 +357,29 @@ m4_define([b4_symbol_type_define],
         Base::clear ();
       }
 
+]b4_parse_error_bmatch(
+[custom\|detailed],
+[[      /// The user-facing name of this symbol.
+      const char *name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }]],
+[simple],
+[[#if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+      /// The user-facing name of this symbol.
+      const char *name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }
+#endif // #if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+]],
+[verbose],
+[[      /// The user-facing name of this symbol.
+      std::string name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }]])[
+
       /// Backward compatibility (Bison 3.6).
       symbol_kind_type type_get () const YY_NOEXCEPT;
 

data/skeletons/lalr1.cc

@@ -256,8 +256,7 @@ m4_define([b4_shared_declarations],
 [verbose],
 [[    /// The user-facing name of the symbol whose (internal) number is
     /// YYSYMBOL.  No bounds checking.
-    static std::string symbol_name (symbol_kind_type yysymbol);
-]])[
+    static std::string symbol_name (symbol_kind_type yysymbol);]])[
 
 ]b4_token_constructor_define[
 ]b4_parse_error_bmatch([custom\|detailed\|verbose], [[
@@ -822,7 +821,7 @@ m4_if(b4_prefix, [yy], [],
       {
         symbol_kind_type yykind = yysym.kind ();
         yyo << (yykind < YYNTOKENS ? "token" : "nterm")
-            << ' ' << symbol_name (yykind) << " ("]b4_locations_if([
+            << ' ' << yysym.name () << " ("]b4_locations_if([
             << yysym.location << ": "])[;
         ]b4_symbol_actions([printer])[
         yyo << ')';

doc/bison.texi

@@ -12154,6 +12154,8 @@ values, which is always less than @code{YYNTOKENS}.
 
 @deftypemethod {parser} {const char *} symbol_name (@code{symbol_kind_t} @var{symbol}) @code{const}
 The name of the symbol whose kind is @var{symbol}, possibly translated.
+
+Returns a @code{std::string} when @code{parse.error} is @code{verbose}.
 @end deftypemethod
 
 A custom syntax error function looks as follows.  This implementation is
@@ -12286,6 +12288,12 @@ applicable) location.
 The kind of this symbol.
 @end deftypemethod
 
+@deftypemethod {symbol_type} {const char *} name () @code{const}
+The name of the kind of this symbol.
+
+Returns a @code{std::string} when @code{parse.error} is @code{verbose}.
+@end deftypemethod
+
 @sp 1
 
 For each token kind, Bison generates named constructors as follows.

tests/c++.at

@@ -162,6 +162,7 @@ int main()
     parser::symbol_type s = parser::make_INT (12);
     assert_eq (s.kind (), parser::symbol_kind::S_INT);
     assert_eq (parser::symbol_name (s.kind ()), "\"int\"");
+    assert_eq (s.name (), "\"int\"");
     assert_eq (s.value.as<int> (), 12);
   }