* src/LR0.c, src/conflicts.c, src/lalr.c, src/lalr.h, src/output.c

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 4fa1aaea9cd3063cc942fcfaa8022247927904da..d76bd6feea7a6a71c7b7642d781026e9b95d1048 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -40,16 +40,18 @@ typedef struct symbol_list
   struct symbol_list *next;
   bucket *sym;
   int line;
   struct symbol_list *next;
   bucket *sym;
   int line;

+

   /* The action is attached to the LHS of a rule. */
   const char *action;
   int action_line;
   /* The action is attached to the LHS of a rule. */
   const char *action;
   int action_line;

+
+  /* The guard is attached to the LHS of a rule. */
+  const char *guard;
+  int guard_line;

   bucket *ruleprec;
   bucket *ruleprec;

-}
-symbol_list;
+} symbol_list;

 
 int lineno;
 
 int lineno;

-char **tags;
-short *user_toknums;

 static symbol_list *grammar;
 static int start_flag;
 static bucket *startval;
 static symbol_list *grammar;
 static int start_flag;
 static bucket *startval;


@@ -64,9 +66,10 @@ static int typed;
 /* Incremented for each %left, %right or %nonassoc seen */
 static int lastprec;
 
 /* Incremented for each %left, %right or %nonassoc seen */
 static int lastprec;
 

-static bucket *errtoken;
-static bucket *undeftoken;
-
+static bucket *errtoken = NULL;
+static bucket *undeftoken = NULL;
+static bucket *eoftoken = NULL;
+static bucket *axiom = NULL;

 
 static symbol_list *
 symbol_list_new (bucket *sym)
 
 static symbol_list *
 symbol_list_new (bucket *sym)


@@ -75,6 +78,10 @@ symbol_list_new (bucket *sym)
   res->next = NULL;
   res->sym = sym;
   res->line = lineno;
   res->next = NULL;
   res->sym = sym;
   res->line = lineno;

+  res->action = NULL;
+  res->action_line = 0;
+  res->guard = NULL;
+  res->guard_line = 0;

   res->ruleprec = NULL;
   return res;
 }
   res->ruleprec = NULL;
   return res;
 }


@@ -326,9 +333,16 @@ copy_at (FILE *fin, struct obstack *oout, int stack_offset)
 
       ungetc (c, fin);
       n = read_signed_integer (fin);
 
       ungetc (c, fin);
       n = read_signed_integer (fin);

-
-      obstack_fgrow1 (oout, "yylsp[%d]", n - stack_offset);
-      locations_flag = 1;
+      if (n > stack_offset)
+       complain (_("invalid value: %s%d"), "@", n);
+      else
+       {
+         /* Offset is always 0 if parser has already popped the stack
+            pointer.  */
+         obstack_fgrow1 (oout, "yylsp[%d]",
+                         n - (semantic_parser ? 0 : stack_offset));
+         locations_flag = 1;
+       }

     }
   else
     {
     }
   else
     {


@@ -383,16 +397,24 @@ copy_dollar (FILE *fin, struct obstack *oout,
       ungetc (c, fin);
       n = read_signed_integer (fin);
 
       ungetc (c, fin);
       n = read_signed_integer (fin);
 

-      if (!type_name && n > 0)
-       type_name = get_type_name (n, rule);
-
-      obstack_fgrow1 (oout, "yyvsp[%d]", n - stack_offset);
-
-      if (type_name)
-       obstack_fgrow1 (oout, ".%s", type_name);
-      if (!type_name && typed)
-       complain (_("$%d of `%s' has no declared type"),
-                 n, rule->sym->tag);
+      if (n > stack_offset)
+       complain (_("invalid value: %s%d"), "$", n);
+      else
+       {
+         if (!type_name && n > 0)
+           type_name = get_type_name (n, rule);
+
+         /* Offset is always 0 if parser has already popped the stack
+            pointer.  */
+         obstack_fgrow1 (oout, "yyvsp[%d]",
+                         n - (semantic_parser ? 0 : stack_offset));
+
+         if (type_name)
+           obstack_fgrow1 (oout, ".%s", type_name);
+         if (!type_name && typed)
+           complain (_("$%d of `%s' has no declared type"),
+                     n, rule->sym->tag);
+       }

     }
   else
     {
     }
   else
     {


@@ -418,7 +440,7 @@ copy_definition (void)
     {
       obstack_fgrow2 (&attrs_obstack, muscle_find ("linef"),
                      lineno, quotearg_style (c_quoting_style,
     {
       obstack_fgrow2 (&attrs_obstack, muscle_find ("linef"),
                      lineno, quotearg_style (c_quoting_style,

-                                             muscle_find("filename")));
+                                             muscle_find ("filename")));

     }
 
   after_percent = 0;
     }
 
   after_percent = 0;


@@ -550,6 +572,9 @@ parse_token_decl (symbol_class what_is, symbol_class what_is_not)
       else if (symbol && token == tok_number)
        {
          symbol->user_token_number = numval;
       else if (symbol && token == tok_number)
        {
          symbol->user_token_number = numval;

+         /* User defined EOF token? */
+         if (numval == 0)
+           eoftoken = symbol;

        }
       else
        {
        }
       else
        {


@@ -874,12 +899,13 @@ parse_thong_decl (void)
   nsyms--;
 }
 
   nsyms--;
 }
 

+

 static void
 parse_muscle_decl (void)
 {
   int ch = ungetc (skip_white_space (), finput);
 static void
 parse_muscle_decl (void)
 {
   int ch = ungetc (skip_white_space (), finput);

-  char* muscle_key;
-  char* muscle_value;
+  char *muscle_key;
+  char *muscle_value;

 
   /* Read key. */
   if (!isalpha (ch) && ch != '_')
 
   /* Read key. */
   if (!isalpha (ch) && ch != '_')


@@ -1072,68 +1098,61 @@ read_declarations (void)
 | matching `}' into the actions file.  STACK_OFFSET is the number of |
 | values in the current rule so far, which says where to find `$0'   |
 | with respect to the top of the stack.                              |
 | matching `}' into the actions file.  STACK_OFFSET is the number of |
 | values in the current rule so far, which says where to find `$0'   |
 | with respect to the top of the stack.                              |

+|                                                                    |
+| This routine is used both for actions and guards.  Only            |
+| ACTION_OBSTACK is used, but this is fine, since we use only        |
+| pointers to relevant portions inside this obstack.                 |

 `-------------------------------------------------------------------*/
 
 static void
 `-------------------------------------------------------------------*/
 
 static void

-copy_action (symbol_list *rule, int stack_offset)
+parse_braces (symbol_list *rule, int stack_offset)

 {
   int c;
   int count;
 
 {
   int c;
   int count;
 

-  /* offset is always 0 if parser has already popped the stack pointer */
-  if (semantic_parser)
-    stack_offset = 0;
-

   count = 1;
   count = 1;

-  c = getc (finput);
-

   while (count > 0)
     {
   while (count > 0)
     {

-      while (c != '}')
-       {
-         switch (c)
-           {
-           case '\n':
-             obstack_1grow (&action_obstack, c);
-             lineno++;
-             break;
-
-           case '{':
-             obstack_1grow (&action_obstack, c);
-             count++;
-             break;
-
-           case '\'':
-           case '"':
-             copy_string (finput, &action_obstack, c);
-             break;
+      while ((c = getc (finput)) != '}')
+       switch (c)
+         {
+         case '\n':
+           obstack_1grow (&action_obstack, c);
+           lineno++;
+           break;

 
 

-           case '/':
-             copy_comment (finput, &action_obstack);
-             break;
+         case '{':
+           obstack_1grow (&action_obstack, c);
+           count++;
+           break;

 
 

-           case '$':
-             copy_dollar (finput, &action_obstack,
-                          rule, stack_offset);
-             break;
+         case '\'':
+         case '"':
+           copy_string (finput, &action_obstack, c);
+           break;

 
 

-           case '@':
-             copy_at (finput, &action_obstack,
-                      stack_offset);
-             break;
+         case '/':
+           copy_comment (finput, &action_obstack);
+           break;

 
 

-           case EOF:
-             fatal (_("unmatched %s"), "`{'");
+         case '$':
+           copy_dollar (finput, &action_obstack,
+                        rule, stack_offset);
+           break;

 
 

-           default:
-             obstack_1grow (&action_obstack, c);
-           }
+         case '@':
+           copy_at (finput, &action_obstack,
+                    stack_offset);
+           break;

 
 

-         c = getc (finput);
-       }
+         case EOF:
+           fatal (_("unmatched %s"), "`{'");

 
 

-      /* above loop exits when c is '}' */
+         default:
+           obstack_1grow (&action_obstack, c);
+         }

 
 

+      /* Above loop exits when C is '}'.  */

       if (--count)
        {
          obstack_1grow (&action_obstack, c);
       if (--count)
        {
          obstack_1grow (&action_obstack, c);


@@ -1142,108 +1161,29 @@ copy_action (symbol_list *rule, int stack_offset)
     }
 
   obstack_1grow (&action_obstack, '\0');
     }
 
   obstack_1grow (&action_obstack, '\0');

-  rule->action = obstack_finish (&action_obstack);
-  rule->action_line = lineno;

 }
 }

-\f
-/*-------------------------------------------------------------------.
-| After `%guard' is seen in the input file, copy the actual guard    |
-| into the guards file.  If the guard is followed by an action, copy |
-| that into the actions file.  STACK_OFFSET is the number of values  |
-| in the current rule so far, which says where to find `$0' with     |
-| respect to the top of the stack, for the simple parser in which    |
-| the stack is not popped until after the guard is run.              |
-`-------------------------------------------------------------------*/
+

 
 static void
 
 static void

-copy_guard (symbol_list *rule, int stack_offset)
+parse_action (symbol_list *rule, int stack_offset)

 {
 {

-  int c;
-  int count;
-  int brace_flag = 0;
-
-  /* offset is always 0 if parser has already popped the stack pointer */
-  if (semantic_parser)
-    stack_offset = 0;
-
-  obstack_fgrow1 (&guard_obstack, "\ncase %d:\n", nrules);
-  if (!no_lines_flag)
-    obstack_fgrow2 (&guard_obstack, muscle_find ("linef"),
-                   lineno, quotearg_style (c_quoting_style,
-                                           muscle_find ("filename")));
-  obstack_1grow (&guard_obstack, '{');
-
-  count = 0;
-  c = getc (finput);
-
-  while (brace_flag ? (count > 0) : (c != ';'))
-    {
-      switch (c)
-       {
-       case '\n':
-         obstack_1grow (&guard_obstack, c);
-         lineno++;
-         break;
-
-       case '{':
-         obstack_1grow (&guard_obstack, c);
-         brace_flag = 1;
-         count++;
-         break;
-
-       case '}':
-         obstack_1grow (&guard_obstack, c);
-         if (count > 0)
-           count--;
-         else
-           {
-             complain (_("unmatched %s"), "`}'");
-             c = getc (finput);        /* skip it */
-           }
-         break;
-
-       case '\'':
-       case '"':
-         copy_string (finput, &guard_obstack, c);
-         break;
-
-       case '/':
-         copy_comment (finput, &guard_obstack);
-         break;
-
-       case '$':
-         copy_dollar (finput, &guard_obstack, rule, stack_offset);
-         break;
-
-       case '@':
-         copy_at (finput, &guard_obstack, stack_offset);
-         break;
-
-       case EOF:
-         fatal ("%s", _("unterminated %guard clause"));
-
-       default:
-         obstack_1grow (&guard_obstack, c);
-       }
-
-      if (c != '}' || count != 0)
-       c = getc (finput);
-    }
+  rule->action_line = lineno;
+  parse_braces (rule, stack_offset);
+  rule->action = obstack_finish (&action_obstack);
+}

 
 

-  c = skip_white_space ();

 
 

-  obstack_sgrow (&guard_obstack, ";\n    break;}");
-  if (c == '{')
-    copy_action (rule, stack_offset);
-  else if (c == '=')
-    {
-      c = getc (finput);       /* why not skip_white_space -wjh */
-      if (c == '{')
-       copy_action (rule, stack_offset);
-    }
-  else
-    ungetc (c, finput);
+static void
+parse_guard (symbol_list *rule, int stack_offset)
+{
+  token_t t = lex ();
+  if (t != tok_left_curly)
+    complain (_("invalid %s declaration"), "%guard");
+  rule->guard_line = lineno;
+  parse_braces (rule, stack_offset);
+  rule->guard = obstack_finish (&action_obstack);

 }
 }

+

 \f
 
 /*-------------------------------------------------------------------.
 \f
 
 /*-------------------------------------------------------------------.


@@ -1446,7 +1386,7 @@ readgram (void)
              }
            else                /* handle an action.  */
              {
              }
            else                /* handle an action.  */
              {

-               copy_action (crule, rulelength);
+               parse_action (crule, rulelength);

                action_flag = 1;
                xactions++;     /* JF */
              }
                action_flag = 1;
                xactions++;     /* JF */
              }


@@ -1465,20 +1405,22 @@ readgram (void)
            crule->ruleprec = symval;
            t = lex ();
          }
            crule->ruleprec = symval;
            t = lex ();
          }

+

        if (t == tok_guard)
          {
            if (!semantic_parser)
              complain (_("%%guard present but %%semantic_parser not specified"));
 
        if (t == tok_guard)
          {
            if (!semantic_parser)
              complain (_("%%guard present but %%semantic_parser not specified"));
 

-           copy_guard (crule, rulelength);
+           parse_guard (crule, rulelength);

            t = lex ();
          }
            t = lex ();
          }

-       else if (t == tok_left_curly)
+
+       if (t == tok_left_curly)

          {
            /* This case never occurs -wjh */
            if (action_flag)
              complain (_("two actions at end of one rule"));
          {
            /* This case never occurs -wjh */
            if (action_flag)
              complain (_("two actions at end of one rule"));

-           copy_action (crule, rulelength);
+           parse_action (crule, rulelength);

            action_flag = 1;
            xactions++; /* -wjh */
            t = lex ();
            action_flag = 1;
            xactions++; /* -wjh */
            t = lex ();


@@ -1507,12 +1449,8 @@ readgram (void)
        t = lex ();
       }
 
        t = lex ();
       }
 

-

   /* grammar has been read.  Do some checking */
 
   /* grammar has been read.  Do some checking */
 

-  if (nsyms > MAXSHORT)
-    fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
-          MAXSHORT);

   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 


@@ -1528,6 +1466,25 @@ readgram (void)
        bp->value = nvars++;
       }
 
        bp->value = nvars++;
       }
 

+  /* Insert the initial rule, which line is that of the first rule
+     (not that of the start symbol):
+
+     axiom: %start EOF.  */
+  p = symbol_list_new (axiom);
+  p->line = grammar->line;
+  p->next = symbol_list_new (startval);
+  p->next->next = symbol_list_new (eoftoken);
+  p->next->next->next = symbol_list_new (NULL);
+  p->next->next->next->next = grammar;
+  nrules += 1;
+  nitems += 3;
+  grammar = p;
+  startval = axiom;
+
+  if (nsyms > MAXSHORT)
+    fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
+          MAXSHORT);
+

   ntokens = nsyms - nvars;
 }
 
   ntokens = nsyms - nvars;
 }
 


@@ -1546,7 +1503,7 @@ read_additionnal_code (void)
     {
       obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
                      lineno, quotearg_style (c_quoting_style,
     {
       obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
                      lineno, quotearg_style (c_quoting_style,

-                                             muscle_find("filename")));
+                                             muscle_find ("filename")));

     }
 
   while ((c = getc (finput)) != EOF)
     }
 
   while ((c = getc (finput)) != EOF)


@@ -1590,18 +1547,17 @@ token_translations_init (void)
       /* A token which translation has already been set? */
       if (token_translations[bp->user_token_number] != 2)
        complain (_("tokens %s and %s both assigned number %d"),
       /* A token which translation has already been set? */
       if (token_translations[bp->user_token_number] != 2)
        complain (_("tokens %s and %s both assigned number %d"),

-                 tags[token_translations[bp->user_token_number]],
+                 symbols[token_translations[bp->user_token_number]]->tag,

                  bp->tag, bp->user_token_number);
       token_translations[bp->user_token_number] = bp->value;
     }
 }
 
 
                  bp->tag, bp->user_token_number);
       token_translations[bp->user_token_number] = bp->value;
     }
 }
 
 

-/*------------------------------------------------------------------.
-| Assign symbol numbers, and write definition of token names into   |
-| FDEFINES.  Set up vectors TAGS and SPREC of names and precedences |
-| of symbols.                                                       |
-`------------------------------------------------------------------*/
+/*----------------------------------------------------------------.
+| Assign symbol numbers, and write definition of token names into |
+| FDEFINES.  Set up vectors SYMBOL_TABLE, TAGS of symbols.        |
+`----------------------------------------------------------------*/

 
 static void
 packsymbols (void)
 
 static void
 packsymbols (void)


@@ -1609,17 +1565,8 @@ packsymbols (void)
   bucket *bp = NULL;
   int tokno = 1;
   int last_user_token_number;
   bucket *bp = NULL;
   int tokno = 1;
   int last_user_token_number;

-  static char DOLLAR[] = "$";
-
-  tags = XCALLOC (char *, nsyms + 1);
-  user_toknums = XCALLOC (short, nsyms + 1);

 
 

-  sprec = XCALLOC (short, nsyms);
-  sassoc = XCALLOC (short, nsyms);
-
-  /* The EOF token. */
-  tags[0] = DOLLAR;
-  user_toknums[0] = 0;
+  symbols = XCALLOC (bucket *, nsyms);

 
   max_user_token_number = 256;
   last_user_token_number = 256;
 
   max_user_token_number = 256;
   last_user_token_number = 256;


@@ -1632,11 +1579,18 @@ packsymbols (void)
        }
       else if (bp->alias)
        {
        }
       else if (bp->alias)
        {

-         /* this symbol and its alias are a single token defn.
-            allocate a tokno, and assign to both check agreement of
-            ->prec and ->assoc fields and make both the same */
-         if (bp->value == 0)
-           bp->value = bp->alias->value = tokno++;
+         /* This symbol and its alias are a single token defn.
+            Allocate a tokno, and assign to both check agreement of
+            prec and assoc fields and make both the same */
+         if (bp->value == -1)
+           {
+             if (bp == eoftoken || bp->alias == eoftoken)
+               bp->value = bp->alias->value = 0;
+             else
+               {
+                 bp->value = bp->alias->value = tokno++;
+               }
+           }

 
          if (bp->prec != bp->alias->prec)
            {
 
          if (bp->prec != bp->alias->prec)
            {


@@ -1662,13 +1616,17 @@ packsymbols (void)
                bp->assoc = bp->alias->assoc;
            }
 
                bp->assoc = bp->alias->assoc;
            }
 

+         /* Do not do processing below for SALIASs.  */

          if (bp->user_token_number == SALIAS)
          if (bp->user_token_number == SALIAS)

-           continue;           /* do not do processing below for SALIASs */
+           continue;

 
        }
 
        }

-      else                     /* bp->class == token_sym */
+      else /* bp->class == token_sym */

        {
        {

-         bp->value = tokno++;
+         if (bp == eoftoken)
+           bp->value = 0;
+         else
+           bp->value = tokno++;

        }
 
       if (bp->class == token_sym)
        }
 
       if (bp->class == token_sym)


@@ -1679,10 +1637,7 @@ packsymbols (void)
            max_user_token_number = bp->user_token_number;
        }
 
            max_user_token_number = bp->user_token_number;
        }
 

-      tags[bp->value] = bp->tag;
-      user_toknums[bp->value] = bp->user_token_number;
-      sprec[bp->value] = bp->prec;
-      sassoc[bp->value] = bp->assoc;
+      symbols[bp->value] = bp;

     }
 
   token_translations_init ();
     }
 
   token_translations_init ();


@@ -1707,13 +1662,11 @@ symbols_save (void)
 {
   struct obstack tokendefs;
   bucket *bp;
 {
   struct obstack tokendefs;
   bucket *bp;

-  char *cp, *symbol;
-  char c;

   obstack_init (&tokendefs);
 
   for (bp = firstsymbol; bp; bp = bp->next)
     {
   obstack_init (&tokendefs);
 
   for (bp = firstsymbol; bp; bp = bp->next)
     {

-      symbol = bp->tag;                /* get symbol */
+      char *symbol = bp->tag;                /* get symbol */

 
       if (bp->value >= ntokens)
        continue;
 
       if (bp->value >= ntokens)
        continue;


@@ -1733,17 +1686,15 @@ symbols_save (void)
        }
 
       /* Don't #define nonliteral tokens whose names contain periods.  */
        }
 
       /* Don't #define nonliteral tokens whose names contain periods.  */

-      cp = symbol;
-      while ((c = *cp++) && c != '.');
-      if (c != '\0')
+      if (strchr (symbol, '.'))

        continue;
 
        continue;
 

-      obstack_fgrow2 (&tokendefs, "# define\t%s\t%d\n",
+      obstack_fgrow2 (&tokendefs, "# define %s\t%d\n",

                      symbol, bp->user_token_number);
       if (semantic_parser)
        /* FIXME: This is probably wrong, and should be just as
           above. --akim.  */
                      symbol, bp->user_token_number);
       if (semantic_parser)
        /* FIXME: This is probably wrong, and should be just as
           above. --akim.  */

-       obstack_fgrow2 (&tokendefs, "# define\tT%s\t%d\n", symbol, bp->value);
+       obstack_fgrow2 (&tokendefs, "# define T%s\t%d\n", symbol, bp->value);

     }
 
   obstack_1grow (&tokendefs, 0);
     }
 
   obstack_1grow (&tokendefs, 0);


@@ -1764,8 +1715,12 @@ packgram (void)
   int ruleno;
   symbol_list *p;
 
   int ruleno;
   symbol_list *p;
 

+  /* We use short to index items.  */
+  if (nitems >= MAXSHORT)
+    fatal (_("too many items (max %d)"), MAXSHORT);
+

   ritem = XCALLOC (short, nitems + 1);
   ritem = XCALLOC (short, nitems + 1);

-  rule_table = XCALLOC (rule_t, nrules) - 1;
+  rules = XCALLOC (rule_t, nrules) - 1;

 
   itemno = 0;
   ruleno = 1;
 
   itemno = 0;
   ruleno = 1;


@@ -1774,12 +1729,14 @@ packgram (void)
   while (p)
     {
       bucket *ruleprec = p->ruleprec;
   while (p)
     {
       bucket *ruleprec = p->ruleprec;

-      rule_table[ruleno].lhs = p->sym->value;
-      rule_table[ruleno].rhs = itemno;
-      rule_table[ruleno].line = p->line;
-      rule_table[ruleno].useful = TRUE;
-      rule_table[ruleno].action = p->action;
-      rule_table[ruleno].action_line = p->action_line;
+      rules[ruleno].lhs = p->sym->value;
+      rules[ruleno].rhs = itemno;
+      rules[ruleno].line = p->line;
+      rules[ruleno].useful = TRUE;
+      rules[ruleno].action = p->action;
+      rules[ruleno].action_line = p->action_line;
+      rules[ruleno].guard = p->guard;
+      rules[ruleno].guard_line = p->guard_line;

 
       p = p->next;
       while (p && p->sym)
 
       p = p->next;
       while (p && p->sym)


@@ -1789,8 +1746,8 @@ packgram (void)
             of the last token in it.  */
          if (p->sym->class == token_sym)
            {
             of the last token in it.  */
          if (p->sym->class == token_sym)
            {

-             rule_table[ruleno].prec = p->sym->prec;
-             rule_table[ruleno].assoc = p->sym->assoc;
+             rules[ruleno].prec = p->sym->prec;
+             rules[ruleno].assoc = p->sym->assoc;

            }
          if (p)
            p = p->next;
            }
          if (p)
            p = p->next;


@@ -1800,9 +1757,9 @@ packgram (void)
          the specified symbol's precedence replaces the default.  */
       if (ruleprec)
        {
          the specified symbol's precedence replaces the default.  */
       if (ruleprec)
        {

-         rule_table[ruleno].prec = ruleprec->prec;
-         rule_table[ruleno].assoc = ruleprec->assoc;
-         rule_table[ruleno].precsym = ruleprec->value;
+         rules[ruleno].prec = ruleprec->prec;
+         rules[ruleno].assoc = ruleprec->assoc;
+         rules[ruleno].precsym = ruleprec->value;

        }
 
       ritem[itemno++] = -ruleno;
        }
 
       ritem[itemno++] = -ruleno;


@@ -1813,6 +1770,8 @@ packgram (void)
     }
 
   ritem[itemno] = 0;
     }
 
   ritem[itemno] = 0;

+  nritems = itemno;
+  assert (nritems == nitems);

 
   if (trace_flag)
     ritem_print (stderr);
 
   if (trace_flag)
     ritem_print (stderr);


@@ -1832,7 +1791,7 @@ reader (void)
   start_flag = 0;
   startval = NULL;             /* start symbol not specified yet. */
 
   start_flag = 0;
   startval = NULL;             /* start symbol not specified yet. */
 

-  nsyms = 1;
+  nsyms = 0;

   nvars = 0;
   nrules = 0;
   nitems = 0;
   nvars = 0;
   nrules = 0;
   nitems = 0;


@@ -1854,6 +1813,11 @@ reader (void)
   /* Initialize the symbol table.  */
   tabinit ();
 
   /* Initialize the symbol table.  */
   tabinit ();
 

+  /* Construct the axiom symbol. */
+  axiom = getsym ("$axiom");
+  axiom->class = nterm_sym;
+  axiom->value = nvars++;
+

   /* Construct the error token */
   errtoken = getsym ("error");
   errtoken->class = token_sym;
   /* Construct the error token */
   errtoken = getsym ("error");
   errtoken->class = token_sym;


@@ -1868,7 +1832,6 @@ reader (void)
   /* Initialize the obstacks. */
   obstack_init (&action_obstack);
   obstack_init (&attrs_obstack);
   /* Initialize the obstacks. */
   obstack_init (&action_obstack);
   obstack_init (&attrs_obstack);

-  obstack_init (&guard_obstack);

   obstack_init (&output_obstack);
 
   finput = xfopen (infile, "r");
   obstack_init (&output_obstack);
 
   finput = xfopen (infile, "r");


@@ -1877,6 +1840,16 @@ reader (void)
      TABLE_OBSTACK and FDEFINES file.  Also notice any %token, %left,
      etc. found there.  */
   read_declarations ();
      TABLE_OBSTACK and FDEFINES file.  Also notice any %token, %left,
      etc. found there.  */
   read_declarations ();

+
+  /* If the user did not define her EOFTOKEN, do it now. */
+  if (!eoftoken)
+    {
+      eoftoken = getsym ("$");
+      eoftoken->class = token_sym;
+      /* Value specified by POSIX.  */
+      eoftoken->user_token_number = 0;
+    }
+

   /* Read in the grammar, build grammar in list form.  Write out
      guards and actions.  */
   readgram ();
   /* Read in the grammar, build grammar in list form.  Write out
      guards and actions.  */
   readgram ();