Merge remote-tracking branch 'origin/maint'

[bison.git] / src / scan-code.l

diff --git a/src/scan-code.l b/src/scan-code.l
index d57eafa3f18af24566fe94d6f0341a7656e19ece..24ef5d920c280a35abea7ccfde6a01b7c2428f65 100644 (file)
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -1,6 +1,6 @@
 /* Bison Action Scanner                             -*- C -*-
 
 /* Bison Action Scanner                             -*- C -*-
 

-   Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2006-2012 Free Software Foundation, Inc.

 
    This file is part of Bison, the GNU Compiler Compiler.
 
 
    This file is part of Bison, the GNU Compiler Compiler.
 


@@ -17,7 +17,7 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 

-%option debug nodefault nounput noyywrap never-interactive
+%option debug nodefault noinput nounput noyywrap never-interactive

 %option prefix="code_" outfile="lex.yy.c"
 
 %{
 %option prefix="code_" outfile="lex.yy.c"
 
 %{


@@ -27,13 +27,14 @@
 #define code_wrap() 1
 
 #define FLEX_PREFIX(Id) code_ ## Id
 #define code_wrap() 1
 
 #define FLEX_PREFIX(Id) code_ ## Id

-#include "flex-scanner.h"
+#include <src/flex-scanner.h>

 
 

-#include "complain.h"
-#include "reader.h"
-#include "getargs.h"
-#include "scan-code.h"
-#include "symlist.h"
+#include <src/complain.h>
+#include <src/reader.h>
+#include <src/getargs.h>
+#include <src/muscle-tab.h>
+#include <src/scan-code.h>
+#include <src/symlist.h>

 
 #include <c-ctype.h>
 #include <get-errno.h>
 
 #include <c-ctype.h>
 #include <get-errno.h>


@@ -47,7 +48,7 @@ YY_DECL;
 #define YY_USER_ACTION  location_compute (loc, &loc->end, yytext, yyleng);
 
 static void handle_action_dollar (symbol_list *rule, char *cp,
 #define YY_USER_ACTION  location_compute (loc, &loc->end, yytext, yyleng);
 
 static void handle_action_dollar (symbol_list *rule, char *cp,

-                                 location dollar_loc);
+                                  location dollar_loc);

 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
 
 /* A string to be pushed to obstack after dollar/at has been handled. */
 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
 
 /* A string to be pushed to obstack after dollar/at has been handled. */


@@ -75,17 +76,17 @@ static bool untyped_var_seen;
 /* POSIX says that a tag must be both an id and a C union member, but
    historically almost any character is allowed in a tag.  We disallow
    NUL and newline, as this simplifies our implementation.  */
 /* POSIX says that a tag must be both an id and a C union member, but
    historically almost any character is allowed in a tag.  We disallow
    NUL and newline, as this simplifies our implementation.  */

-tag     [^\0\n>]+
+tag      [^\0\n>]+

 
 /* Zero or more instances of backslash-newline.  Following GCC, allow
    white space between the backslash and the newline.  */
 
 /* Zero or more instances of backslash-newline.  Following GCC, allow
    white space between the backslash and the newline.  */

-splice  (\\[ \f\t\v]*\n)*
+splice   (\\[ \f\t\v]*\n)*

 
 /* C style identifier. Must start with letter. Will be used for
    named symbol references. Shall be kept synchronized with
    scan-gram.l "letter" and "id". */
 
 /* C style identifier. Must start with letter. Will be used for
    named symbol references. Shall be kept synchronized with
    scan-gram.l "letter" and "id". */

-letter   [-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
-id       {letter}({letter}|[0-9])*
+letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
+id        {letter}({letter}|[-0-9])*

 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 %%
 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 %%


@@ -95,10 +96,10 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
   int braces_level = 0;
 
   /* Whether a semicolon is probably needed.
   int braces_level = 0;
 
   /* Whether a semicolon is probably needed.

-     The heuristic is that a semicolon is not needed after `{', `}', `;',
+     The heuristic is that a semicolon is not needed after '{', '}', ';',

      or a C preprocessor directive, and that whitespaces and comments
      do not affect this flag.
      or a C preprocessor directive, and that whitespaces and comments
      do not affect this flag.

-     Note that `{' does not need a semicolon because of `{}'.
+     Note that '{' does not need a semicolon because of '{}'.

      A semicolon may be needed before a cpp direcive, but don't bother.  */
   bool need_semicolon = false;
 
      A semicolon may be needed before a cpp direcive, but don't bother.  */
   bool need_semicolon = false;
 


@@ -111,13 +112,13 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
      is expected to return only once.  This initialization is
      therefore done once per action to translate. */
   aver (sc_context == SC_SYMBOL_ACTION
      is expected to return only once.  This initialization is
      therefore done once per action to translate. */
   aver (sc_context == SC_SYMBOL_ACTION

-       || sc_context == SC_RULE_ACTION
-       || sc_context == INITIAL);
+        || sc_context == SC_RULE_ACTION
+        || sc_context == INITIAL);

   BEGIN sc_context;
 %}
 
   /*------------------------------------------------------------.
   BEGIN sc_context;
 %}
 
   /*------------------------------------------------------------.

-  | Scanning a C comment.  The initial `/ *' is already eaten.  |
+  | Scanning a C comment.  The initial '/ *' is already eaten.  |

   `------------------------------------------------------------*/
 
 <SC_COMMENT>
   `------------------------------------------------------------*/
 
 <SC_COMMENT>


@@ -127,13 +128,13 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 
   /*--------------------------------------------------------------.
 
 
   /*--------------------------------------------------------------.

-  | Scanning a line comment.  The initial `//' is already eaten.  |
+  | Scanning a line comment.  The initial '//' is already eaten.  |

   `--------------------------------------------------------------*/
 
 <SC_LINE_COMMENT>
 {
   `--------------------------------------------------------------*/
 
 <SC_LINE_COMMENT>
 {

-  "\n"          STRING_GROW; BEGIN sc_context;
-  {splice}      STRING_GROW;
+  "\n"           STRING_GROW; BEGIN sc_context;
+  {splice}       STRING_GROW;

 }
 
 
 }
 
 


@@ -143,17 +144,17 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 <SC_CHARACTER,SC_STRING>
 {
 
 <SC_CHARACTER,SC_STRING>
 {

-  {splice}|\\{splice}. STRING_GROW;
+  {splice}|\\{splice}.  STRING_GROW;

 }
 
 <SC_CHARACTER>
 {
 }
 
 <SC_CHARACTER>
 {

-  "'"          STRING_GROW; BEGIN sc_context;
+  "'"           STRING_GROW; BEGIN sc_context;

 }
 
 <SC_STRING>
 {
 }
 
 <SC_STRING>
 {

-  "\""         STRING_GROW; BEGIN sc_context;
+  "\""          STRING_GROW; BEGIN sc_context;

 }
 
 
 }
 
 


@@ -197,12 +198,12 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
     need_semicolon = true;
   }
   "$"  {
     need_semicolon = true;
   }
   "$"  {

-    warn_at (*loc, _("stray `$'"));
+    complain_at (*loc, Wother, _("stray '$'"));

     obstack_sgrow (&obstack_for_string, "$][");
     need_semicolon = true;
   }
   "@"  {
     obstack_sgrow (&obstack_for_string, "$][");
     need_semicolon = true;
   }
   "@"  {

-    warn_at (*loc, _("stray `@'"));
+    complain_at (*loc, Wother, _("stray '@'"));

     obstack_sgrow (&obstack_for_string, "@@");
     need_semicolon = true;
   }
     obstack_sgrow (&obstack_for_string, "@@");
     need_semicolon = true;
   }


@@ -220,16 +221,18 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
   "}"  {
     bool outer_brace = --braces_level == 0;
 
   "}"  {
     bool outer_brace = --braces_level == 0;
 

-    /* As an undocumented Bison extension, append `;' before the last
+    /* As an undocumented Bison extension, append ';' before the last

        brace in braced code, so that the user code can omit trailing
        brace in braced code, so that the user code can omit trailing

-       `;'.  But do not append `;' if emulating Yacc, since Yacc does
+       ';'.  But do not append ';' if emulating Yacc, since Yacc does

        not append one.  */
     if (outer_brace && !yacc_flag && language_prio == default_prio
         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
       {
        not append one.  */
     if (outer_brace && !yacc_flag && language_prio == default_prio
         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
       {

-       warn_at (*loc, _("a `;' might be needed at the end of action code"));
-       warn_at (*loc, _("future versions of Bison will not add the `;'"));
-       obstack_1grow (&obstack_for_string, ';');
+        complain_at (*loc, Wother,
+                     _("a ';' might be needed at the end of action code"));
+        complain_at (*loc, Wother,
+                     _("future versions of Bison will not add the ';'"));
+        obstack_1grow (&obstack_for_string, ';');

       }
 
     STRING_GROW;
       }
 
     STRING_GROW;


@@ -238,14 +241,27 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
   /* Preprocessing directives should only be recognized at the beginning
      of lines, allowing whitespace including comments, but in C/C++,
 
   /* Preprocessing directives should only be recognized at the beginning
      of lines, allowing whitespace including comments, but in C/C++,

-     `#' can only be the start of preprocessor directives or within
-     `#define' directives anyway, so don't bother with begin of line.  */
+     '#' can only be the start of preprocessor directives or within
+     '#define' directives anyway, so don't bother with begin of line.  */

   "#"       STRING_GROW; in_cpp = true;
 
   {splice}  STRING_GROW;
   "#"       STRING_GROW; in_cpp = true;
 
   {splice}  STRING_GROW;

-  [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false; 
+  [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;

   [ \t\f]   STRING_GROW;
   [ \t\f]   STRING_GROW;

-  .         STRING_GROW; need_semicolon = true;
+
+  /* YYFAIL is undocumented and was formally deprecated in Bison
+     2.4.2.  */
+  YYFAIL {
+    STRING_GROW; need_semicolon = true;
+    complain_at (*loc, Wother,
+                 _("use of YYFAIL, which is deprecated and will be removed"));
+  }
+
+  /* The sole purpose of this is to make sure identifiers that merely
+     contain YYFAIL don't produce the above warning.  */
+  [A-Za-z_][0-9A-Za-z_]* STRING_GROW; need_semicolon = true;
+
+  . STRING_GROW; need_semicolon = true;

 }
 
 <SC_SYMBOL_ACTION>
 }
 
 <SC_SYMBOL_ACTION>


@@ -256,7 +272,7 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
   }
   "@$" {
     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
   }
   "@$" {
     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");

-    locations_flag = true;
+    muscle_percent_define_ensure("locations", the_location, true);

   }
 }
 
   }
 }
 


@@ -267,20 +283,20 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 <*>
 {
 
 <*>
 {

-  \$   obstack_sgrow (&obstack_for_string, "$][");
-  \@   obstack_sgrow (&obstack_for_string, "@@");
-  \[   obstack_sgrow (&obstack_for_string, "@{");
-  \]   obstack_sgrow (&obstack_for_string, "@}");
+  \$    obstack_sgrow (&obstack_for_string, "$][");
+  \@    obstack_sgrow (&obstack_for_string, "@@");
+  \[    obstack_sgrow (&obstack_for_string, "@{");
+  \]    obstack_sgrow (&obstack_for_string, "@}");

 }
 
   /*-----------------------------------------------------.
   | By default, grow the string obstack with the input.  |
   `-----------------------------------------------------*/
 
 }
 
   /*-----------------------------------------------------.
   | By default, grow the string obstack with the input.  |
   `-----------------------------------------------------*/
 

-<*>.|\n        STRING_GROW;
+<*>.|\n STRING_GROW;

 
  /* End of processing. */
 
  /* End of processing. */

-<*><<EOF>>      {
+<*><<EOF>>       {

                    STRING_FINISH;
                    return last_string;
                  }
                    STRING_FINISH;
                    return last_string;
                  }


@@ -306,7 +322,7 @@ contains_dot_or_dash (const char* p)
 typedef struct
 {
   /* Index in symbol list. */
 typedef struct
 {
   /* Index in symbol list. */

-  unsigned index;
+  unsigned symbol_index;

 
   /* Matched symbol id and loc. */
   uniqstr id;
 
   /* Matched symbol id and loc. */
   uniqstr id;


@@ -337,24 +353,23 @@ static unsigned variant_table_size = 0;
 static unsigned variant_count = 0;
 
 static variant *
 static unsigned variant_count = 0;
 
 static variant *

-variant_table_grow ()
+variant_table_grow (void)

 {
   ++variant_count;
   if (variant_count > variant_table_size)
     {
       while (variant_count > variant_table_size)
 {
   ++variant_count;
   if (variant_count > variant_table_size)
     {
       while (variant_count > variant_table_size)

-       variant_table_size = 2 * variant_table_size + 3;
+        variant_table_size = 2 * variant_table_size + 3;

       variant_table = xnrealloc (variant_table, variant_table_size,
       variant_table = xnrealloc (variant_table, variant_table_size,

-                                sizeof *variant_table);
+                                 sizeof *variant_table);

     }
   return &variant_table[variant_count - 1];
 }
 
 static void
     }
   return &variant_table[variant_count - 1];
 }
 
 static void

-variant_table_free ()
+variant_table_free (void)

 {
 {

-  if (variant_table)
-    free (variant_table);
+  free (variant_table);

   variant_table = 0;
   variant_table_size = variant_count = 0;
 }
   variant_table = 0;
   variant_table_size = variant_count = 0;
 }


@@ -375,20 +390,20 @@ find_prefix_end (const char *prefix, char *begin, char *end)
 }
 
 static variant *
 }
 
 static variant *

-variant_add (uniqstr id, location loc, unsigned index,
-            char *cp, char *cp_end, bool exact_mode)
+variant_add (uniqstr id, location id_loc, unsigned symbol_index,
+             char *cp, char *cp_end, bool explicit_bracketing)

 {
   char *prefix_end;
 
   prefix_end = find_prefix_end (id, cp, cp_end);
   if (prefix_end &&
       (prefix_end == cp_end ||
 {
   char *prefix_end;
 
   prefix_end = find_prefix_end (id, cp, cp_end);
   if (prefix_end &&
       (prefix_end == cp_end ||

-       (!exact_mode && is_dot_or_dash (*prefix_end))))
+       (!explicit_bracketing && is_dot_or_dash (*prefix_end))))

     {
       variant *r = variant_table_grow ();
     {
       variant *r = variant_table_grow ();

-      r->index = index;
+      r->symbol_index = symbol_index;

       r->id = id;
       r->id = id;

-      r->loc = loc;
+      r->loc = id_loc;

       r->hidden_by = NULL;
       r->err = 0;
       return r;
       r->hidden_by = NULL;
       r->err = 0;
       return r;


@@ -398,38 +413,115 @@ variant_add (uniqstr id, location loc, unsigned index,
 }
 
 static const char *
 }
 
 static const char *

-get_at_spec(unsigned index)
+get_at_spec(unsigned symbol_index)

 {
   static char at_buf[20];
 {
   static char at_buf[20];

-  if (index == 0)
+  if (symbol_index == 0)

     strcpy (at_buf, "$$");
   else
     strcpy (at_buf, "$$");
   else

-    snprintf (at_buf, sizeof at_buf, "$%u", index);
+    snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);

   return at_buf;
 }
 
   return at_buf;
 }
 

+static void
+show_sub_messages (const char* cp, bool explicit_bracketing,
+                   int midrule_rhs_index, char dollar_or_at,
+                   bool is_warning, unsigned indent)
+{
+  unsigned i;
+
+  for (i = 0; i < variant_count; ++i)
+    {
+      const variant *var = &variant_table[i];
+      const char *at_spec = get_at_spec (var->symbol_index);
+
+      if (var->err == 0)
+        {
+          if (is_warning)
+            complain_at_indent (var->loc, Wother, &indent,
+                                _("refers to: %c%s at %s"), dollar_or_at,
+                                var->id, at_spec);
+          else
+            complain_at_indent (var->loc, complaint, &indent,
+                                _("refers to: %c%s at %s"), dollar_or_at,
+                                var->id, at_spec);
+        }
+      else
+        {
+          static struct obstack msg_buf;
+          const char *tail = explicit_bracketing ? "" :
+            cp + strlen (var->id);
+          const char *id = var->hidden_by ? var->hidden_by->id :
+            var->id;
+          location id_loc = var->hidden_by ? var->hidden_by->loc :
+            var->loc;
+
+          /* Create the explanation message. */
+          obstack_init (&msg_buf);
+
+          obstack_fgrow1 (&msg_buf, _("possibly meant: %c"), dollar_or_at);
+          if (contains_dot_or_dash (id))
+            obstack_fgrow1 (&msg_buf, "[%s]", id);
+          else
+            obstack_sgrow (&msg_buf, id);
+          obstack_sgrow (&msg_buf, tail);
+
+          if (var->err & VARIANT_HIDDEN)
+            {
+              obstack_fgrow1 (&msg_buf, _(", hiding %c"), dollar_or_at);
+              if (contains_dot_or_dash (var->id))
+                obstack_fgrow1 (&msg_buf, "[%s]", var->id);
+              else
+                obstack_sgrow (&msg_buf, var->id);
+              obstack_sgrow (&msg_buf, tail);
+            }
+
+          obstack_fgrow1 (&msg_buf, _(" at %s"), at_spec);
+
+          if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
+            {
+              const char *format =
+                _(", cannot be accessed from mid-rule action at $%d");
+              obstack_fgrow1 (&msg_buf, format, midrule_rhs_index);
+            }
+
+          obstack_1grow (&msg_buf, '\0');
+          if (is_warning)
+            complain_at_indent (id_loc, Wother, &indent, "%s",
+                                (char *) obstack_finish (&msg_buf));
+          else
+            complain_at_indent (id_loc, complaint, &indent, "%s",
+                                (char *) obstack_finish (&msg_buf));
+          obstack_free (&msg_buf, 0);
+        }
+    }
+}
+

 /* Returned from "parse_ref" when the reference
    is inappropriate. */
 #define INVALID_REF (INT_MIN)
 
 /* Returned from "parse_ref" when the reference
 /* Returned from "parse_ref" when the reference
    is inappropriate. */
 #define INVALID_REF (INT_MIN)
 
 /* Returned from "parse_ref" when the reference

-   points to LHS ($$) of the current rule. */
+   points to LHS ($$) of the current rule or midrule. */

 #define LHS_REF (INT_MIN + 1)
 
 #define LHS_REF (INT_MIN + 1)
 

+/* Sub-messages indent. */
+#define SUB_INDENT (4)
+

 /* Parse named or positional reference. In case of positional
    references, can return negative values for $-n "deep" stack
    accesses. */
 static long int
 parse_ref (char *cp, symbol_list *rule, int rule_length,
 /* Parse named or positional reference. In case of positional
    references, can return negative values for $-n "deep" stack
    accesses. */
 static long int
 parse_ref (char *cp, symbol_list *rule, int rule_length,

-          int midrule_rhs_index, char *text, location loc,
-          char dollar_or_at)
+           int midrule_rhs_index, char *text, location text_loc,
+           char dollar_or_at)

 {
   symbol_list *l;
   char *cp_end;
 {
   symbol_list *l;
   char *cp_end;

-  bool exact_mode;
-  bool has_error;
-  bool has_valid;
+  bool explicit_bracketing;

   unsigned i;
   unsigned i;

+  unsigned valid_variants = 0;
+  unsigned valid_variant_index = 0;

 
   if ('$' == *cp)
     return LHS_REF;
 
   if ('$' == *cp)
     return LHS_REF;


@@ -438,12 +530,13 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
     {
       long int num = strtol (cp, &cp, 10);
       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
     {
       long int num = strtol (cp, &cp, 10);
       if (1 - INT_MAX + rule_length <= num && num <= rule_length)

-       return num;
+        return num;

       else
       else

-       {
-         complain_at (loc, _("integer out of range: %s"), quote (text));
-         return INVALID_REF;
-       }
+        {
+          complain_at (text_loc, complaint, _("integer out of range: %s"),
+                       quote (text));
+          return INVALID_REF;
+        }

     }
 
   if ('[' == *cp)
     }
 
   if ('[' == *cp)


@@ -451,159 +544,147 @@ parse_ref (char *cp, symbol_list *rule, int rule_length,
       /* Ignore the brackets. */
       char *p;
       for (p = ++cp; *p != ']'; ++p)
       /* Ignore the brackets. */
       char *p;
       for (p = ++cp; *p != ']'; ++p)

-       continue;
+        continue;

       cp_end = p;
 
       cp_end = p;
 

-      exact_mode = true;
+      explicit_bracketing = true;

     }
   else
     {
       /* Take all characters of the name. */
       char* p;
       for (p = cp; *p; ++p)
     }
   else
     {
       /* Take all characters of the name. */
       char* p;
       for (p = cp; *p; ++p)

-       if (is_dot_or_dash (*p))
-         {
-           ref_tail_fields = p;
-           break;
-         }
+        if (is_dot_or_dash (*p))
+          {
+            ref_tail_fields = p;
+            break;
+          }

       for (p = cp; *p; ++p)
       for (p = cp; *p; ++p)

-       continue;
+        continue;

       cp_end = p;
 
       cp_end = p;
 

-      exact_mode = false;
+      explicit_bracketing = false;

     }
 
   /* Add all relevant variants. */
   {
     }
 
   /* Add all relevant variants. */
   {

-    unsigned index;
+    unsigned symbol_index;

     variant_count = 0;
     variant_count = 0;

-    for (index = 0, l = rule; !symbol_list_null (l); ++index, l = l->next)
+    for (symbol_index = 0, l = rule; !symbol_list_null (l);
+         ++symbol_index, l = l->next)

       {
       {

-       variant *variant;
-       if (l->content_type != SYMLIST_SYMBOL)
-         continue;
-
-       variant = variant_add (l->content.sym->tag, l->sym_loc, index,
-                              cp, cp_end, exact_mode);
-
-       if (variant && l->named_ref)
-         variant->hidden_by = l->named_ref;
-
-       if (l->named_ref)
-         variant_add (l->named_ref->id, l->named_ref->loc, index,
-                      cp, cp_end, exact_mode);
+        variant *var;
+        if (l->content_type != SYMLIST_SYMBOL)
+          continue;
+
+        var = variant_add (l->content.sym->tag, l->sym_loc,
+                           symbol_index, cp, cp_end, explicit_bracketing);
+        if (var && l->named_ref)
+          var->hidden_by = l->named_ref;
+
+        if (l->named_ref)
+          variant_add (l->named_ref->id, l->named_ref->loc,
+                       symbol_index, cp, cp_end, explicit_bracketing);

       }
   }
 
   /* Check errors. */
       }
   }
 
   /* Check errors. */

-  has_error = false;
-  has_valid = false;

   for (i = 0; i < variant_count; ++i)
     {
   for (i = 0; i < variant_count; ++i)
     {

-      variant *variant = &variant_table[i];
-      unsigned index = variant->index;
+      variant *var = &variant_table[i];
+      unsigned symbol_index = var->symbol_index;

 
       /* Check visibility from mid-rule actions. */
       if (midrule_rhs_index != 0
 
       /* Check visibility from mid-rule actions. */
       if (midrule_rhs_index != 0

-         && (index == 0 || midrule_rhs_index < index))
-       {
-         variant->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
-         has_error = true;
-       }
+          && (symbol_index == 0 || midrule_rhs_index < symbol_index))
+        var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;

 
       /* Check correct bracketing. */
 
       /* Check correct bracketing. */

-      if (!exact_mode && contains_dot_or_dash (variant->id))
-       {
-         variant->err |= VARIANT_BAD_BRACKETING;
-         has_error = true;
-       }
+      if (!explicit_bracketing && contains_dot_or_dash (var->id))
+        var->err |= VARIANT_BAD_BRACKETING;

 
       /* Check using of hidden symbols. */
 
       /* Check using of hidden symbols. */

-      if (variant->hidden_by)
-       {
-         variant->err |= VARIANT_HIDDEN;
-         has_error = true;
-       }
-
-      if (!variant->err)
-       has_valid = true;
+      if (var->hidden_by)
+        var->err |= VARIANT_HIDDEN;
+
+      if (!var->err)
+        {
+          valid_variant_index = i;
+          ++valid_variants;
+        }

     }
 
     }
 

-  if (variant_count == 1 && has_valid)
+  switch (valid_variants)

     {
     {

-      /* The only "good" case is here. */
-      unsigned index = variant_table[0].index;
-      if (index == midrule_rhs_index)
-       return LHS_REF;
-      else
-       return index;
-    }
-
-  /* Start complaining. */
-
-  if (variant_count == 0)
-    complain_at (loc, _("invalid reference: %s, symbol not found"),
-                quote (text));
-  else if (variant_count > 1 && !has_error)
-    complain_at (loc, _("ambiguous reference: %s"),
-                quote (text));
-  else if (variant_count > 1 && has_valid && has_error)
-    complain_at (loc, _("misleading reference: %s"),
-                quote (text));
-  else
-    complain_at (loc, _("invalid reference: %s"),
-                quote (text));
-
-  for (i = 0; i < variant_count; ++i)
-    {
-      const variant *variant = &variant_table[i];
-      const char *at_spec = get_at_spec (variant->index);
-
-      if (variant->err == 0)
-       complain_at (variant->loc, _("  refers to: %c%s at %s"),
-                    dollar_or_at, variant->id, at_spec);
-      else
-       {
-         static struct obstack msg_buf;
-         const char *tail = exact_mode ? "" :
-           cp + strlen (variant->id);
-         const char *id = variant->hidden_by ? variant->hidden_by->id :
-           variant->id;
-         location loc = variant->hidden_by ? variant->hidden_by->loc :
-           variant->loc;
-
-         /* Create the explanation message. */
-         obstack_init (&msg_buf);
-
-         obstack_fgrow1 (&msg_buf, "  possibly meant: %c", dollar_or_at);
-         if (contains_dot_or_dash (id))
-           obstack_fgrow1 (&msg_buf, "[%s]", id);
-         else
-           obstack_sgrow (&msg_buf, id);
-         obstack_sgrow (&msg_buf, tail);
-
-         if (variant->err & VARIANT_HIDDEN)
-           {
-             obstack_fgrow1 (&msg_buf, ", hiding %c", dollar_or_at);
-             if (contains_dot_or_dash (variant->id))
-               obstack_fgrow1 (&msg_buf, "[%s]", variant->id);
-             else
-               obstack_sgrow (&msg_buf, variant->id);
-             obstack_sgrow (&msg_buf, tail);
-           }
-
-         obstack_fgrow1 (&msg_buf, " at %s", at_spec);
-
-         if (variant->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
-           obstack_fgrow1 (&msg_buf, ", cannot be accessed from "
-                           "mid-rule action at $%d", midrule_rhs_index);
-
-         obstack_1grow (&msg_buf, '\0');
-         complain_at (loc, _("%s"), (char *) obstack_finish (&msg_buf));
-         obstack_free (&msg_buf, 0);
-       }
+    case 0:
+      {
+        unsigned len = (explicit_bracketing || !ref_tail_fields) ?
+          cp_end - cp : ref_tail_fields - cp;
+        unsigned indent = 0;
+
+        complain_at_indent (text_loc, complaint, &indent,
+                            _("invalid reference: %s"), quote (text));
+        indent += SUB_INDENT;
+        if (len == 0)
+          {
+            location sym_loc = text_loc;
+            sym_loc.start.column += 1;
+            sym_loc.end = sym_loc.start;
+            const char *format =
+              _("syntax error after '%c', expecting integer, letter,"
+                " '_', '[', or '$'");
+            complain_at_indent (sym_loc, complaint, &indent, format,
+                                dollar_or_at);
+          }
+        else if (midrule_rhs_index)
+          {
+            const char *format =
+              _("symbol not found in production before $%d: %.*s");
+            complain_at_indent (rule->location, complaint, &indent, format,
+                                midrule_rhs_index, len, cp);
+          }
+        else
+          {
+            const char *format =
+              _("symbol not found in production: %.*s");
+            complain_at_indent (rule->location, complaint, &indent, format,
+                                len, cp);
+          }
+
+        if (variant_count > 0)
+          show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+                             dollar_or_at, false, indent);
+        return INVALID_REF;
+      }
+    case 1:
+      {
+        unsigned indent = 0;
+        if (variant_count > 1)
+          {
+            complain_at_indent (text_loc, Wother, &indent,
+                                _("misleading reference: %s"), quote (text));
+            show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+                               dollar_or_at, true, indent + SUB_INDENT);
+          }
+        {
+          unsigned symbol_index =
+            variant_table[valid_variant_index].symbol_index;
+          return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
+        }
+      }
+    case 2:
+    default:
+      {
+        unsigned indent = 0;
+        complain_at_indent (text_loc, complaint, &indent,
+                            _("ambiguous reference: %s"), quote (text));
+        show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+                           dollar_or_at, false, indent + SUB_INDENT);
+        return INVALID_REF;
+      }

     }
 
     }
 

+  /* Not reachable. */

   return INVALID_REF;
 }
 
   return INVALID_REF;
 }
 


@@ -614,7 +695,7 @@ int max_left_semantic_context = 0;
 
 
 /*------------------------------------------------------------------.
 
 
 /*------------------------------------------------------------------.

-| TEXT is pointing to a wannabee semantic value (i.e., a `$').      |
+| TEXT is pointing to a wannabee semantic value (i.e., a '$').      |

 |                                                                   |
 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 |                                                                   |
 |                                                                   |
 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 |                                                                   |


@@ -647,19 +728,20 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
     {
       type_name = ++cp;
       while (*cp != '>')
     {
       type_name = ++cp;
       while (*cp != '>')

-       ++cp;
+        ++cp;

 
       /* The '>' symbol will be later replaced by '\0'. Original
 
       /* The '>' symbol will be later replaced by '\0'. Original

-        'text' is needed for error messages. */
+         'text' is needed for error messages. */

       gt_ptr = cp;
       ++cp;
       if (untyped_var_seen)
       gt_ptr = cp;
       ++cp;
       if (untyped_var_seen)

-       complain_at (dollar_loc, _("explicit type given in untyped grammar"));
+        complain_at (dollar_loc, complaint,
+                  _("explicit type given in untyped grammar"));

       tag_seen = true;
     }
 
   n = parse_ref (cp, effective_rule, effective_rule_length,
       tag_seen = true;
     }
 
   n = parse_ref (cp, effective_rule, effective_rule_length,

-                rule->midrule_parent_rhs_index, text, dollar_loc, '$');
+                 rule->midrule_parent_rhs_index, text, dollar_loc, '$');

 
   if (gt_ptr)
     *gt_ptr = '\0';
 
   if (gt_ptr)
     *gt_ptr = '\0';


@@ -671,61 +753,63 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 
     case LHS_REF:
       if (!type_name)
 
     case LHS_REF:
       if (!type_name)

-       type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
+        type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);

 
       if (!type_name)
 
       if (!type_name)

-       {
-         if (union_seen | tag_seen)
-           {
-             if (rule->midrule_parent_rule)
-               complain_at (dollar_loc,
-                            _("$$ for the midrule at $%d of `%s'"
-                              " has no declared type"),
-                            rule->midrule_parent_rhs_index,
-                            effective_rule->content.sym->tag);
-             else
-               complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
-                            rule->content.sym->tag);
-           }
-         else
-           untyped_var_seen = true;
-         type_name = "";
-       }
+        {
+          if (union_seen | tag_seen)
+            {
+              if (rule->midrule_parent_rule)
+                complain_at (dollar_loc, complaint,
+                             _("$$ for the midrule at $%d of %s"
+                               " has no declared type"),
+                             rule->midrule_parent_rhs_index,
+                             quote (effective_rule->content.sym->tag));
+              else
+                complain_at (dollar_loc, complaint,
+                             _("$$ of %s has no declared type"),
+                             quote (rule->content.sym->tag));
+            }
+          else
+            untyped_var_seen = true;
+          type_name = "";
+        }

 
       obstack_fgrow1 (&obstack_for_string,
 
       obstack_fgrow1 (&obstack_for_string,

-                     "]b4_lhs_value([%s])[", type_name);
+                      "]b4_lhs_value([%s])[", type_name);

       rule->action_props.is_value_used = true;
       break;
 
     default:
       if (max_left_semantic_context < 1 - n)
       rule->action_props.is_value_used = true;
       break;
 
     default:
       if (max_left_semantic_context < 1 - n)

-       max_left_semantic_context = 1 - n;
+        max_left_semantic_context = 1 - n;

       if (!type_name && 0 < n)
       if (!type_name && 0 < n)

-       type_name =
-         symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
+        type_name =
+          symbol_list_n_type_name_get (effective_rule, dollar_loc, n);

       if (!type_name)
       if (!type_name)

-       {
-         if (union_seen | tag_seen)
-           complain_at (dollar_loc, _("$%s of `%s' has no declared type"),
-                        cp, effective_rule->content.sym->tag);
-         else
-           untyped_var_seen = true;
-         type_name = "";
-       }
+        {
+          if (union_seen | tag_seen)
+            complain_at (dollar_loc, complaint,
+                         _("$%s of %s has no declared type"), cp,
+                         quote (effective_rule->content.sym->tag));
+          else
+            untyped_var_seen = true;
+          type_name = "";
+        }

 
       obstack_fgrow3 (&obstack_for_string,
 
       obstack_fgrow3 (&obstack_for_string,

-                     "]b4_rhs_value(%d, %d, [%s])[",
-                     effective_rule_length, n, type_name);
+                      "]b4_rhs_value(%d, %d, [%s])[",
+                      effective_rule_length, n, type_name);

       if (n > 0)
       if (n > 0)

-       symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
-         true;
+        symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
+          true;

       break;
     }
 }
 
 
 /*------------------------------------------------------.
       break;
     }
 }
 
 
 /*------------------------------------------------------.

-| TEXT is a location token (i.e., a `@...').  Output to |
+| TEXT is a location token (i.e., a '@...').  Output to |

 | OBSTACK_FOR_STRING a reference to this location.      |
 `------------------------------------------------------*/
 
 | OBSTACK_FOR_STRING a reference to this location.      |
 `------------------------------------------------------*/
 


@@ -748,10 +832,10 @@ handle_action_at (symbol_list *rule, char *text, location at_loc)
       effective_rule_length = symbol_list_length (rule->next);
     }
 
       effective_rule_length = symbol_list_length (rule->next);
     }
 

-  locations_flag = true;
+  muscle_percent_define_ensure("locations", at_loc, true);

 
   n = parse_ref (cp, effective_rule, effective_rule_length,
 
   n = parse_ref (cp, effective_rule, effective_rule_length,

-                      rule->midrule_parent_rhs_index, text, at_loc, '@');
+                       rule->midrule_parent_rhs_index, text, at_loc, '@');

   switch (n)
     {
     case INVALID_REF:
   switch (n)
     {
     case INVALID_REF:


@@ -763,7 +847,7 @@ handle_action_at (symbol_list *rule, char *text, location at_loc)
 
     default:
       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 
     default:
       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",

-                     effective_rule_length, n);
+                      effective_rule_length, n);

       break;
     }
 }
       break;
     }
 }


@@ -810,39 +894,36 @@ code_props const code_props_none = CODE_PROPS_NONE_INIT;
 
 void
 code_props_plain_init (code_props *self, char const *code,
 
 void
 code_props_plain_init (code_props *self, char const *code,

-                      location code_loc)
+                       location code_loc)

 {
 {

+  code_props_none_init (self);

   self->kind = CODE_PROPS_PLAIN;
   self->code = code;
   self->location = code_loc;
   self->kind = CODE_PROPS_PLAIN;
   self->code = code;
   self->location = code_loc;

-  self->is_value_used = false;
-  self->rule = NULL;
-  self->named_ref = NULL;

 }
 
 void
 code_props_symbol_action_init (code_props *self, char const *code,
                                location code_loc)
 {
 }
 
 void
 code_props_symbol_action_init (code_props *self, char const *code,
                                location code_loc)
 {

+  code_props_none_init (self);

   self->kind = CODE_PROPS_SYMBOL_ACTION;
   self->code = code;
   self->location = code_loc;
   self->kind = CODE_PROPS_SYMBOL_ACTION;
   self->code = code;
   self->location = code_loc;

-  self->is_value_used = false;
-  self->rule = NULL;
-  self->named_ref = NULL;

 }
 
 void
 code_props_rule_action_init (code_props *self, char const *code,
                              location code_loc, symbol_list *rule,
 }
 
 void
 code_props_rule_action_init (code_props *self, char const *code,
                              location code_loc, symbol_list *rule,

-                            named_ref *named_ref)
+                             named_ref *name, bool is_predicate)

 {
 {

+  code_props_none_init (self);

   self->kind = CODE_PROPS_RULE_ACTION;
   self->code = code;
   self->location = code_loc;
   self->kind = CODE_PROPS_RULE_ACTION;
   self->code = code;
   self->location = code_loc;

-  self->is_value_used = false;

   self->rule = rule;
   self->rule = rule;

-  self->named_ref = named_ref;
+  self->named_ref = name;
+  self->is_predicate = is_predicate;

 }
 
 void
 }
 
 void