glr2.cc: move state_stack into the unnamed namespace

* data/skeletons/glr2.cc: here.
Prefer `using` to `typedef`, this is C++11.
Use the type alias we introduced.

data/skeletons/glr2.cc

@@ -1660,12 +1660,15 @@ void glr_state::destroy (char const* yymsg, ]b4_namespace_ref[::]b4_parser_class
 #undef YYFILL
 #define YYFILL(N) yyfill (yyvsp, yylow, (N), yynormal)
 
-class state_stack
+namespace
 {
-public:
-  typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind symbol_kind;
-  typedef ]b4_namespace_ref[::]b4_parser_class[::value_type value_type;]b4_locations_if([[
-  typedef ]b4_namespace_ref[::]b4_parser_class[::location_type location_type;]])[
+  class state_stack
+  {
+  public:
+    using parser_type = ]b4_namespace_ref[::]b4_parser_class[;
+    using symbol_kind = parser_type::symbol_kind;
+    using value_type = parser_type::value_type;]b4_locations_if([[
+    using location_type = parser_type::location_type;]])[
 
     /** Initialize to a single empty stack, with total maximum
      *  capacity for all stacks of YYSIZE.  */
@@ -1683,7 +1686,7 @@ public:
       return YYHEADROOM <= spaceLeft () || yyexpandGLRStack ();
     }
 
-private:
+  private:
     /** If *this is expandable, extend it.  WARNING: Pointers into the
         stack from outside should be considered invalid after this call.
         We always expand when there are 1 or fewer items left AFTER an
@@ -1719,7 +1722,7 @@ private:
       return true;
     }
 
-public:
+  public:
 #else
     bool yyexpandGLRStackIfNeeded ()
     {
@@ -1951,7 +1954,7 @@ public:
 
     void
     yy_reduce_print (bool yynormal, glr_stack_item* yyvsp, state_set_index yyk,
-                   rule_num yyrule, ]b4_namespace_ref[::]b4_parser_class[& yyparser)
+                     rule_num yyrule, parser_type& yyparser)
     {
       int yynrhs = yyrhsLength (yyrule);]b4_locations_if([
       int yylow = 1;])[
@@ -2015,7 +2018,7 @@ public:
 
     YYRESULTTAG
     yyreportAmbiguity (const semantic_option& yyx0,
-                     const semantic_option& yyx1, ]b4_namespace_ref[::]b4_parser_class[& yyparser]b4_locations_if([, const location_type& yyloc])[)
+                       const semantic_option& yyx1, parser_type& yyparser]b4_locations_if([, const location_type& yyloc])[)
     {
       YY_USE (yyx0);
       YY_USE (yyx1);
@@ -2033,7 +2036,6 @@ public:
       return yyabort;
     }
 
-  /* DEBUGGING ONLY */
 #if ]b4_api_PREFIX[DEBUG
     /* Print YYS (possibly NULL) and its predecessors. */
     void
@@ -2047,7 +2049,7 @@ public:
     }
 #endif
 
-private:
+  private:
     size_t spaceLeft() const
     {
       return yyitems.capacity() - yyitems.size();
@@ -2066,13 +2068,13 @@ private:
     }
 
 
-public:
-
+  public:
     std::vector<glr_stack_item> yyitems;
     // Where the stack splits. Anything below this address is deterministic.
     const glr_state* yysplitPoint;
     glr_state_set yytops;
-};
+  }; // class state_stack
+} // namespace
 
 #undef YYFILL
 #define YYFILL(N) yystateStack.yyfill (yyvsp, yylow, (N), yynormal)
@@ -2095,7 +2097,7 @@ namespace ]b4_namespace_ref[
     friend context;
   ]])[
 
-    glr_stack (size_t yysize, ]b4_namespace_ref[::]b4_parser_class[& yyparser_yyarg]m4_ifset([b4_parse_param], [, b4_parse_param_decl])[)
+    glr_stack (size_t yysize, parser_type& yyparser_yyarg]m4_ifset([b4_parse_param], [, b4_parse_param_decl])[)
       : yyerrState (0)
       , yystateStack (yysize)
       , yyerrcnt (0)
@@ -2118,7 +2120,7 @@ namespace ]b4_namespace_ref[
     int yyerrcnt;
     symbol_type yyla;
     YYJMP_BUF yyexception_buffer;
-    ]b4_namespace_ref[::]b4_parser_class[& yyparser;
+    parser_type& yyparser;
 
   #define YYCHK1(YYE)                                                          \
     do {                                                                       \
@@ -2607,7 +2609,7 @@ namespace ]b4_namespace_ref[
        so pretend the stack is "normal". */
     YY_REDUCE_PRINT ((yynormal || yyk == create_state_set_index (-1), yyvsp, yyk, yyrule, yyparser));
     #if YY_EXCEPTIONS
-      typedef ]b4_namespace_ref[::]b4_parser_class[::syntax_error syntax_error;
+      typedef parser_type::syntax_error syntax_error;
       try
       {
     #endif // YY_EXCEPTIONS
@@ -3085,7 +3087,7 @@ namespace ]b4_namespace_ref[
               yyla.kind_ = yyparser.yytranslate_ (]b4_yylex[);]])[
             }
 #if YY_EXCEPTIONS
-          catch (const ]b4_namespace_ref[::]b4_parser_class[::syntax_error& yyexc)
+          catch (const parser_type::syntax_error& yyexc)
             {
               YYCDEBUG << "Caught exception: " << yyexc.what () << '\n';]b4_locations_if([
               this->yyla.location = yyexc.location;])[