glr2.cc: get rid of the yyerror scaffolding

[Akim Demaille]

With more TODO :)

commit f3f7f6e1dca60cae09146f0a6439477a055567e1
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Sat Sep 5 07:37:34 2020 +0200

    glr2.cc: get rid of the yyerror scaffolding
    
    The yyerror stand-alone function was used to bounce from glr.c's call
    to yyerror to glr.cc's parser.error.  Now that glr.c is out of the
    way, just directly use parser.error.
    
    * data/skeletons/glr2.cc (yyerror): Remove.
    Adjust callers.
    (b4_yyerror_args, b4_lyyerror_args, b4_pure_formals): Remove.
    Now unused.

diff --git a/TODO b/TODO
index 5e0149cd..5c3210d2 100644
--- a/TODO
+++ b/TODO
@@ -187,6 +187,13 @@ It should be a member of the parser object, see lalr1.cc.  
Let the parser
 object decide what the debug stream is, rather than open coding std::cerr.
 And use YYCDEBUG rather than YY_DEBUG_STREAM.
 
+*** Avoid pointers
+There are many places where pointers should be replaced with references.
+
+*** Use proper type names
+Don't use YYSTYPE and YYLTYPE but parser::semantic_type and
+parser::location_type.  Undefine YYSTYPE and YYLTYPE.
+
 * Chains
 ** Unit rules / Injection rules (Akim Demaille)
 Maybe we could expand unit rules (or "injections", see
diff --git a/data/skeletons/glr2.cc b/data/skeletons/glr2.cc
index 81ee2299..b69a74bb 100644
--- a/data/skeletons/glr2.cc
+++ b/data/skeletons/glr2.cc
@@ -86,15 +86,6 @@ yy_symbol_print (FILE *, 
]b4_namespace_ref[::]b4_parser_class[& yyparser, ]b4_na
 [yylloc.initialize ();]m4_ifdef([b4_initial_action], [
 m4_defn([b4_initial_action])]))])[
 
-# Hijack the post prologue to declare yyerror.
-]m4_append([b4_post_prologue],
-[b4_syncline([@oline@], [@ofile@])dnl
-[static void
-yyerror (]b4_namespace_ref[::]b4_parser_class[& yyparser, 
]b4_locations_if([[const ]b4_namespace_ref::b4_parser_class[::location_type 
*yylocationp,
-         ]])[]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param),
-         ])[const std::string& msg);]])[
-
-
 ]m4_define([b4_define_symbol_kind],
 [m4_format([#define %-15s %s],
            b4_symbol($][1, kind_base),
@@ -396,32 +387,16 @@ m4_define([b4_user_formals],
 [m4_ifset([b4_parse_param], [, b4_user_formals_no_comma])])
 
 # b4_user_formals_no_comma
-# ---------------
+# ------------------------
 # The possible parse-params formal arguments.
 m4_define([b4_user_formals_no_comma],
 [m4_ifset([b4_parse_param], [b4_formals(b4_parse_param)])])
 
-# b4_yyerror_args
-# ---------------
-# Optional effective arguments passed to yyerror: user args plus yylloc, and
-# a trailing comma.
-m4_define([b4_yyerror_args],
-[yyparser, b4_pure_if([b4_locations_if([yylocp, ])])dnl
-m4_ifset([b4_parse_param], [b4_args(b4_parse_param), ])])
-
-
-
-# b4_lyyerror_args
-# ----------------
-# Same as above, but on the lookahead, hence &yylloc instead of yylocp.
-m4_define([b4_lyyerror_args],
-[yyparser, []b4_pure_if([b4_locations_if([&yylloc, ])])dnl
-m4_ifset([b4_parse_param], [b4_args(b4_parse_param), ])])
-
 
 # b4_pure_args
 # ------------
-# Same as b4_yyerror_args, but with a leading comma.
+# Optional effective arguments passed to yyerror: user args plus yylloc, and
+# a leading comma.
 m4_define([b4_pure_args],
 [b4_pure_if([b4_locations_if([, yylocp])])[]b4_user_args])
 
@@ -433,14 +408,6 @@ m4_define([b4_lpure_args],
 [b4_pure_if([b4_locations_if([, &yylloc])])[]b4_user_args])
 
 
-
-# b4_pure_formals
-# ---------------
-# Arguments passed to yyerror: user formals plus yylocp with leading comma.
-m4_define([b4_pure_formals],
-[b4_pure_if([b4_locations_if([, YYLTYPE *yylocp])])[]b4_user_formals])
-
-
 # b4_locuser_formals(LOC = yylocp)
 # --------------------------------
 # User formal arguments, possibly preceded by location argument.
@@ -1733,7 +1700,7 @@ struct yyStateStack {
 
   YYRESULTTAG
   yyreportAmbiguity (yySemanticOption* yyx0,
-                     yySemanticOption* yyx1, 
]b4_namespace_ref[::]b4_parser_class[& yyparser]b4_pure_formals[)
+                     yySemanticOption* yyx1, 
]b4_namespace_ref[::]b4_parser_class[& yyparser]b4_locations_if([, YYLTYPE 
*yylocp])[)
   {
     YYUSE (yyx0);
     YYUSE (yyx1);
@@ -1747,7 +1714,7 @@ struct yyStateStack {
     std::cerr << "\n";
 #endif
 
-    yyerror (]b4_yyerror_args[YY_("syntax is ambiguous"));
+    yyparser.error (]b4_locations_if([*yylocp, ])[YY_("syntax is ambiguous"));
     return yyabort;
   }
 
@@ -1895,7 +1862,7 @@ struct yyGLRStack {
   yyFail (]b4_locations_if([YYLTYPE* yylocp, ])[const char* yymsg)
   {
     if (yymsg != YY_NULLPTR)
-      yyerror (]b4_yyerror_args[yymsg);
+      yyparser.error (]b4_locations_if([*yylocp, ])[yymsg);
     YYLONGJMP (yyexception_buffer, 1);
   }
 
@@ -1937,7 +1904,7 @@ struct yyGLRStack {
       return;
 ]b4_parse_error_bmatch(
 [simple],
-[[    yyerror (]b4_lyyerror_args[YY_("syntax error"));]],
+[[    yyparser.error (]b4_locations_if([yylloc, ])[YY_("syntax error"));]],
 [[    {
     ]b4_namespace_ref::b4_parser_class[::symbol_kind_type yytoken
       = yychar == ]b4_namespace_ref::b4_parser_class::token::b4_symbol(-2, id)[
@@ -2030,7 +1997,7 @@ struct yyGLRStack {
         }
       else
         yymsg += *yyp;
-     yyerror (]b4_lyyerror_args[yymsg);
+     yyparser.error (]b4_locations_if([[yylloc, ]])[yymsg);
     }
 ]])[
     yynerrs += 1;
@@ -2231,7 +2198,7 @@ struct yyGLRStack {
   # define yyclearin (yychar = 
]b4_namespace_ref::b4_parser_class::token::b4_symbol(-2, id)[)
   # undef YYBACKUP
   # define YYBACKUP(Token, Value)                                              
\
-    return yyerror (]b4_yyerror_args[YY_("syntax error: cannot back up")),     
\
+    return yyparser.error (]b4_locations_if([*yylocp, ])[YY_("syntax error: 
cannot back up")),     \
            yyerrok, yyerr
 
     yylow = 1;
@@ -2259,7 +2226,7 @@ struct yyGLRStack {
       {
         YY_DEBUG_STREAM  << "Caught exception: " << yyexc.what() << 
'\n';]b4_locations_if([
         *yylocp = yyexc.location;])[
-        yyerror (]b4_yyerror_args[yyexc.what ());
+        yyparser.error (]b4_locations_if([*yylocp, ])[yyexc.what ());
         YYERROR;
       }
   #endif // YY_EXCEPTIONS
@@ -2530,7 +2497,7 @@ struct yyGLRStack {
               {
               case 0:]b4_locations_if([[
                 yyresolveLocations (yys, 1);]])[
-                return yystateStack.yyreportAmbiguity (yybest, yyp, 
yyparser]b4_pure_args[);
+                return yystateStack.yyreportAmbiguity (yybest, yyp, 
yyparser]b4_locations_if([, yylocp])[);
                 break;
               case 1:
                 yymerge = true;
@@ -2699,7 +2666,7 @@ yygetToken (int *yycharp, 
]b4_namespace_ref[::]b4_parser_class[& yyparser][]b4_p
         {
           YY_DEBUG_STREAM <<  "Caught exception: " << yyexc.what() << 
"\n";]b4_locations_if([
           yylloc = yyexc.location;])[
-          yyerror (]b4_lyyerror_args[yyexc.what ());
+          yyparser.error (]b4_locations_if([yylloc, ])[yyexc.what ());
           // Map errors caught in the scanner to the error token, so that error
           // handling is started.
           *yycharp = ]b4_namespace_ref::b4_parser_class::token::b4_symbol(1, 
id)[;
@@ -3014,7 +2981,7 @@ b4_dollar_popdef])[]dnl
   goto yyreturn;
 
  yyexhaustedlab:
-  yyerror (]b4_lyyerror_args[YY_("memory exhausted"));
+  yyparser.error (]b4_locations_if([yylloc, ])[YY_("memory exhausted"));
   yyresult = 2;
   goto yyreturn;
 
@@ -3057,15 +3024,6 @@ m4_if(b4_prefix, [yy], [],
 | Report an error.  |
 `------------------*/
 
-static void
-yyerror (]b4_namespace_ref[::]b4_parser_class[& yyparser, 
]b4_locations_if([[const ]b4_namespace_ref::b4_parser_class[::location_type 
*yylocationp,
-         ]])[]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param),
-         ])[const std::string& msg)
-{
-]b4_parse_param_use[]dnl
-[  yyparser.error (]b4_locations_if([[*yylocationp, ]])[msg);
-}
-
 
 ]b4_namespace_open[
 ]dnl In this section, the parse params are the original parse_params.