X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/0e78e603f696b4b820231b56fdb21c2a173e6bd3..5e424082ced49dcbe89b76aed509161b4e914cee:/src/reader.c?ds=sidebyside

diff --git a/src/reader.c b/src/reader.c
index c1cbb097..f2bc42e7 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,5 +1,5 @@
 /* Input parser for bison
-   Copyright 1984, 1986, 1989, 1992, 1998, 2000, 2001
+   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -38,43 +38,28 @@
 typedef struct symbol_list
 {
   struct symbol_list *next;
-  bucket *sym;
+  symbol_t *sym;
   int 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;
+  symbol_t *ruleprec;
 } symbol_list;
 
 int lineno;
-char **tags;
-short *user_toknums;
-static symbol_list *grammar;
-static int start_flag;
-static bucket *startval;
-
-/* Nonzero if components of semantic values are used, implying
-   they must be unions.  */
-static int value_components_used;
+static symbol_list *grammar = NULL;
+static int start_flag = 0;
 
 /* Nonzero if %union has been seen.  */
-static int typed;
+static int typed = 0;
 
 /* Incremented for each %left, %right or %nonassoc seen */
-static int lastprec;
-
-static bucket *errtoken = NULL;
-static bucket *undeftoken = NULL;
-static bucket *eoftoken = NULL;
-static bucket *axiom = NULL;
+static int lastprec = 0;
 
 static symbol_list *
-symbol_list_new (bucket *sym)
+symbol_list_new (symbol_t *sym)
 {
   symbol_list *res = XMALLOC (symbol_list, 1);
   res->next = NULL;
@@ -82,14 +67,10 @@ symbol_list_new (bucket *sym)
   res->line = lineno;
   res->action = NULL;
   res->action_line = 0;
-  res->guard = NULL;
-  res->guard_line = 0;
   res->ruleprec = NULL;
   return res;
 }
 
-
-
 /*===================\
 | Low level lexing.  |
 \===================*/
@@ -167,12 +148,34 @@ get_type_name (int n, symbol_list *rule)
 	  complain (_("invalid $ value"));
 	  return NULL;
 	}
-      i++;
+      ++i;
     }
 
   return rp->sym->type_name;
 }
 
+/*------------------------------------------------------------------.
+| Copy the character C to OOUT, and insert quadigraphs when needed. |
+`------------------------------------------------------------------*/
+
+static inline void
+copy_character (struct obstack *oout, int c)
+{
+  switch (c)
+    {
+    case '[':
+      obstack_sgrow (oout, "@<:@");
+      break;
+
+    case ']':
+      obstack_sgrow (oout, "@:>@");
+      break;
+
+    default:
+      obstack_1grow (oout, c);
+    }
+}
+
 /*------------------------------------------------------------.
 | Dump the string from FIN to OOUT if non null.  MATCH is the |
 | delimiter of the string (either ' or ").                    |
@@ -200,17 +203,17 @@ copy_string2 (FILE *fin, struct obstack *oout, int match, int store)
 	  continue;
 	}
 
-      obstack_1grow (oout, c);
+      copy_character (oout, c);
 
       if (c == '\\')
 	{
 	  c = getc (fin);
 	  if (c == EOF)
 	    fatal (_("unterminated string at end of file"));
-	  obstack_1grow (oout, c);
+	  copy_character (oout, c);
 
 	  if (c == '\n')
-	    lineno++;
+	    ++lineno;
 	}
 
       c = getc (fin);
@@ -293,7 +296,7 @@ copy_comment (FILE *fin, struct obstack *oout)
 	}
       else if (c == '\n')
 	{
-	  lineno++;
+	  ++lineno;
 	  obstack_1grow (oout, c);
 	  if (cplus_comment)
 	    ended = 1;
@@ -304,30 +307,29 @@ copy_comment (FILE *fin, struct obstack *oout)
 	fatal (_("unterminated comment"));
       else
 	{
-	  obstack_1grow (oout, c);
+	  copy_character (oout, c);
 	  c = getc (fin);
 	}
     }
 }
 
 
-/*-----------------------------------------------------------------.
-| FIN is pointing to a location (i.e., a `@').  Output to OOUT a   |
-| reference to this location. 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.                                 |
-`-----------------------------------------------------------------*/
+/*-------------------------------------------------------------------.
+| FIN is pointing to a location (i.e., a `@').  Output to OOUT a     |
+| reference to this location. RULE_LENGTH 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.                                   |
+`-------------------------------------------------------------------*/
 
 static inline void
-copy_at (FILE *fin, struct obstack *oout, int stack_offset)
+copy_at (FILE *fin, struct obstack *oout, int rule_length)
 {
-  int c;
+  int c = getc (fin);
+  locations_flag = 1;
 
-  c = getc (fin);
   if (c == '$')
     {
-      obstack_sgrow (oout, "yyloc");
-      locations_flag = 1;
+      obstack_sgrow (oout, "]b4_lhs_location[");
     }
   else if (isdigit (c) || c == '-')
     {
@@ -335,16 +337,11 @@ copy_at (FILE *fin, struct obstack *oout, int stack_offset)
 
       ungetc (c, fin);
       n = read_signed_integer (fin);
-      if (n > stack_offset)
+      if (n > rule_length)
 	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;
-	}
+	obstack_fgrow2 (oout, "]b4_rhs_location([%d], [%d])[",
+			rule_length, n);
     }
   else
     {
@@ -355,19 +352,19 @@ copy_at (FILE *fin, struct obstack *oout, int stack_offset)
 }
 
 
-/*-------------------------------------------------------------------.
-| FIN is pointing to a wannabee semantic value (i.e., a `$').        |
-|                                                                    |
-| Possible inputs: $[<TYPENAME>]($|integer)                          |
-|                                                                    |
-| Output to OOUT a reference to this semantic value. STACK_OFFSET is |
-| the number of values in the current rule so far, which says where  |
-| to find `$0' with respect to the top of the stack.                 |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| FIN is pointing to a wannabee semantic value (i.e., a `$').       |
+|                                                                   |
+| Possible inputs: $[<TYPENAME>]($|integer)                         |
+|                                                                   |
+| Output to OOUT a reference to this semantic value. RULE_LENGTH 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.                |
+`------------------------------------------------------------------*/
 
 static inline void
 copy_dollar (FILE *fin, struct obstack *oout,
-	     symbol_list *rule, int stack_offset)
+	     symbol_list *rule, int rule_length)
 {
   int c = getc (fin);
   const char *type_name = NULL;
@@ -377,21 +374,20 @@ copy_dollar (FILE *fin, struct obstack *oout,
     {
       read_type_name (fin);
       type_name = token_buffer;
-      value_components_used = 1;
       c = getc (fin);
     }
 
   if (c == '$')
     {
-      obstack_sgrow (oout, "yyval");
-
       if (!type_name)
 	type_name = get_type_name (0, rule);
-      if (type_name)
-	obstack_fgrow1 (oout, ".%s", type_name);
       if (!type_name && typed)
 	complain (_("$$ of `%s' has no declared type"),
 		  rule->sym->tag);
+      if (!type_name)
+	type_name = "";
+      obstack_fgrow1 (oout,
+		      "]b4_lhs_value([%s])[", type_name);
     }
   else if (isdigit (c) || c == '-')
     {
@@ -399,23 +395,19 @@ copy_dollar (FILE *fin, struct obstack *oout,
       ungetc (c, fin);
       n = read_signed_integer (fin);
 
-      if (n > stack_offset)
+      if (n > rule_length)
 	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);
+	  if (!type_name)
+	    type_name = "";
+	  obstack_fgrow3 (oout, "]b4_rhs_value([%d], [%d], [%s])[",
+			  rule_length, n, type_name);
 	}
     }
   else
@@ -432,7 +424,7 @@ copy_dollar (FILE *fin, struct obstack *oout,
 `-------------------------------------------------------------------*/
 
 static void
-copy_definition (void)
+copy_definition (struct obstack *oout)
 {
   int c;
   /* -1 while reading a character if prev char was %. */
@@ -440,7 +432,7 @@ copy_definition (void)
 
   if (!no_lines_flag)
     {
-      obstack_fgrow2 (&attrs_obstack, muscle_find ("linef"),
+      obstack_fgrow2 (oout, muscle_find ("linef"),
 		      lineno, quotearg_style (c_quoting_style,
 					      muscle_find ("filename")));
     }
@@ -454,8 +446,8 @@ copy_definition (void)
       switch (c)
 	{
 	case '\n':
-	  obstack_1grow (&attrs_obstack, c);
-	  lineno++;
+	  obstack_1grow (oout, c);
+	  ++lineno;
 	  break;
 
 	case '%':
@@ -464,18 +456,18 @@ copy_definition (void)
 
 	case '\'':
 	case '"':
-	  copy_string (finput, &attrs_obstack, c);
+	  copy_string (finput, oout, c);
 	  break;
 
 	case '/':
-	  copy_comment (finput, &attrs_obstack);
+	  copy_comment (finput, oout);
 	  break;
 
 	case EOF:
 	  fatal ("%s", _("unterminated `%{' definition"));
 
 	default:
-	  obstack_1grow (&attrs_obstack, c);
+	  copy_character (oout, c);
 	}
 
       c = getc (finput);
@@ -484,27 +476,25 @@ copy_definition (void)
 	{
 	  if (c == '}')
 	    return;
-	  obstack_1grow (&attrs_obstack, '%');
+	  obstack_1grow (oout, '%');
 	}
       after_percent = 0;
     }
 }
 
 
-/*-------------------------------------------------------------------.
-| Parse what comes after %token or %nterm.  For %token, WHAT_IS is   |
-| token_sym and WHAT_IS_NOT is nterm_sym.  For %nterm, the arguments |
-| are reversed.                                                      |
-`-------------------------------------------------------------------*/
+/*------------------------------------------.
+| Parse what comes after %token or %nterm.  |
+`------------------------------------------*/
 
 static void
-parse_token_decl (symbol_class what_is, symbol_class what_is_not)
+parse_token_decl (symbol_class class)
 {
   token_t token = tok_undef;
   char *typename = NULL;
 
   /* The symbol being defined.  */
-  struct bucket *symbol = NULL;
+  symbol_t *symbol = NULL;
 
   /* After `%token' and `%nterm', any number of symbols maybe be
      defined.  */
@@ -520,69 +510,40 @@ parse_token_decl (symbol_class what_is, symbol_class what_is_not)
 	fatal (_("Premature EOF after %s"), token_buffer);
 
       token = lex ();
-      if (token == tok_comma)
+      switch (token)
 	{
+	case tok_comma:
 	  symbol = NULL;
-	  continue;
-	}
-      if (token == tok_typename)
-	{
+	  break;
+
+	case tok_typename:
 	  typename = xstrdup (token_buffer);
-	  value_components_used = 1;
 	  symbol = NULL;
-	}
-      else if (token == tok_identifier && *symval->tag == '\"' && symbol)
-	{
-	  if (symval->alias)
-	    warn (_("symbol `%s' used more than once as a literal string"),
-		  symval->tag);
-	  else if (symbol->alias)
-	    warn (_("symbol `%s' given more than one literal string"),
-		  symbol->tag);
+	  break;
+
+	case tok_identifier:
+	  if (*symval->tag == '\"' && symbol)
+	    {
+	      symbol_make_alias (symbol, symval, typename);
+	      symbol = NULL;
+	    }
 	  else
 	    {
-	      symval->class = token_sym;
-	      symval->type_name = typename;
-	      symval->user_token_number = symbol->user_token_number;
-	      symbol->user_token_number = SALIAS;
-	      symval->alias = symbol;
-	      symbol->alias = symval;
-	      /* symbol and symval combined are only one symbol */
-	      nsyms--;
+	      symbol = symval;
+	      symbol_class_set (symbol, class);
+	      if (typename)
+		symbol_type_set (symbol, typename);
 	    }
- 	  symbol = NULL;
-	}
-      else if (token == tok_identifier)
-	{
-	  int oldclass = symval->class;
-	  symbol = symval;
+	  break;
 
-	  if (symbol->class == what_is_not)
-	    complain (_("symbol %s redefined"), symbol->tag);
-	  symbol->class = what_is;
-	  if (what_is == nterm_sym && oldclass != nterm_sym)
-	    symbol->value = nvars++;
+	case tok_number:
+	  symbol_user_token_number_set (symbol, numval);
+	  break;
 
-	  if (typename)
-	    {
-	      if (symbol->type_name == NULL)
-		symbol->type_name = typename;
-	      else if (strcmp (typename, symbol->type_name) != 0)
-		complain (_("type redeclaration for %s"), symbol->tag);
-	    }
-	}
-      else if (symbol && token == tok_number)
-	{
-	  symbol->user_token_number = numval;
-	  /* User defined EOF token? */
-	  if (numval == 0)
-	    eoftoken = symbol;
-	}
-      else
-	{
+	default:
 	  complain (_("`%s' is invalid in %s"),
 		    token_buffer,
-		    (what_is == token_sym) ? "%token" : "%nterm");
+		    (class == token_sym) ? "%token" : "%nterm");
 	  skip_to_char ('%');
 	}
     }
@@ -604,7 +565,7 @@ parse_start_decl (void)
   else
     {
       start_flag = 1;
-      startval = symval;
+      startsymbol = symval;
     }
 }
 
@@ -641,17 +602,12 @@ parse_type_decl (void)
 
       switch (t)
 	{
-
 	case tok_comma:
 	case tok_semicolon:
 	  break;
 
 	case tok_identifier:
-	  if (symval->type_name == NULL)
-	    symval->type_name = name;
-	  else if (strcmp (name, symval->type_name) != 0)
-	    complain (_("type redeclaration for %s"), symval->tag);
-
+	  symbol_type_set (symval, name);
 	  break;
 
 	default:
@@ -675,7 +631,8 @@ parse_assoc_decl (associativity assoc)
   char *name = NULL;
   int prev = 0;
 
-  lastprec++;			/* Assign a new precedence level, never 0.  */
+  /* Assign a new precedence level, never 0.  */
+  ++lastprec;
 
   for (;;)
     {
@@ -699,32 +656,22 @@ parse_assoc_decl (associativity assoc)
 	  break;
 
 	case tok_identifier:
-	  if (symval->prec != 0)
-	    complain (_("redefining precedence of %s"), symval->tag);
-	  symval->prec = lastprec;
-	  symval->assoc = assoc;
-	  if (symval->class == nterm_sym)
-	    complain (_("symbol %s redefined"), symval->tag);
-	  symval->class = token_sym;
+	  symbol_class_set (symval, token_sym);
+	  symbol_precedence_set (symval, lastprec, assoc);
 	  if (name)
-	    {			/* record the type, if one is specified */
-	      if (symval->type_name == NULL)
-		symval->type_name = name;
-	      else if (strcmp (name, symval->type_name) != 0)
-		complain (_("type redeclaration for %s"), symval->tag);
-	    }
+	    symbol_type_set (symval, name);
 	  break;
 
 	case tok_number:
 	  if (prev == tok_identifier)
 	    {
-	      symval->user_token_number = numval;
+	      symbol_user_token_number_set (symval, numval);
 	    }
 	  else
 	    {
-	      complain (_
-			("invalid text (%s) - number should be after identifier"),
-token_buffer);
+	      complain
+		(_("invalid text (%s) - number should be after identifier"),
+		 token_buffer);
 	      skip_to_char ('%');
 	    }
 	  break;
@@ -761,6 +708,7 @@ parse_union_decl (void)
 
   typed = 1;
 
+  MUSCLE_INSERT_INT ("stype_line", lineno);
   obstack_init (&union_obstack);
   obstack_sgrow (&union_obstack, "union");
 
@@ -775,7 +723,7 @@ parse_union_decl (void)
       switch (c)
 	{
 	case '\n':
-	  lineno++;
+	  ++lineno;
 	  break;
 
 	case '/':
@@ -783,7 +731,7 @@ parse_union_decl (void)
 	  break;
 
 	case '{':
-	  count++;
+	  ++count;
 	  break;
 
 	case '}':
@@ -824,84 +772,6 @@ parse_expect_decl (void)
 }
 
 
-/*-------------------------------------------------------------------.
-| Parse what comes after %thong.  the full syntax is                 |
-|                                                                    |
-|                %thong <type> token number literal                  |
-|                                                                    |
-| the <type> or number may be omitted.  The number specifies the     |
-| user_token_number.                                                 |
-|                                                                    |
-| Two symbols are entered in the table, one for the token symbol and |
-| one for the literal.  Both are given the <type>, if any, from the  |
-| declaration.  The ->user_token_number of the first is SALIAS and   |
-| the ->user_token_number of the second is set to the number, if     |
-| any, from the declaration.  The two symbols are linked via         |
-| pointers in their ->alias fields.                                  |
-|                                                                    |
-| During OUTPUT_DEFINES_TABLE, the symbol is reported thereafter,    |
-| only the literal string is retained it is the literal string that  |
-| is output to yytname                                               |
-`-------------------------------------------------------------------*/
-
-static void
-parse_thong_decl (void)
-{
-  token_t token;
-  struct bucket *symbol;
-  char *typename = 0;
-  int usrtoknum = SUNDEF;
-
-  token = lex ();		/* fetch typename or first token */
-  if (token == tok_typename)
-    {
-      typename = xstrdup (token_buffer);
-      value_components_used = 1;
-      token = lex ();		/* fetch first token */
-    }
-
-  /* process first token */
-
-  if (token != tok_identifier)
-    {
-      complain (_("unrecognized item %s, expected an identifier"),
-		token_buffer);
-      skip_to_char ('%');
-      return;
-    }
-  symval->class = token_sym;
-  symval->type_name = typename;
-  symval->user_token_number = SALIAS;
-  symbol = symval;
-
-  token = lex ();		/* get number or literal string */
-
-  if (token == tok_number)
-    {
-      usrtoknum = numval;
-      token = lex ();		/* okay, did number, now get literal */
-    }
-
-  /* process literal string token */
-
-  if (token != tok_identifier || *symval->tag != '\"')
-    {
-      complain (_("expected string constant instead of %s"), token_buffer);
-      skip_to_char ('%');
-      return;
-    }
-  symval->class = token_sym;
-  symval->type_name = typename;
-  symval->user_token_number = usrtoknum;
-
-  symval->alias = symbol;
-  symbol->alias = symval;
-
-  /* symbol and symval combined are only one symbol.  */
-  nsyms--;
-}
-
-
 static void
 parse_muscle_decl (void)
 {
@@ -997,7 +867,7 @@ parse_skel_decl (void)
 /*----------------------------------------------------------------.
 | Read from finput until `%%' is seen.  Discard the `%%'.  Handle |
 | any `%' declarations, and copy the contents of any `%{ ... %}'  |
-| groups to ATTRS_OBSTACK.                                        |
+| groups to PRE_PROLOGUE_OBSTACK or POST_PROLOGUE_OBSTACK.        |
 `----------------------------------------------------------------*/
 
 static void
@@ -1017,15 +887,18 @@ read_declarations (void)
 	      return;
 
 	    case tok_percent_left_curly:
-	      copy_definition ();
+              if (!typed)
+		copy_definition (&pre_prologue_obstack);
+	      else
+		copy_definition (&post_prologue_obstack);
 	      break;
 
 	    case tok_token:
-	      parse_token_decl (token_sym, nterm_sym);
+	      parse_token_decl (token_sym);
 	      break;
 
 	    case tok_nterm:
-	      parse_token_decl (nterm_sym, token_sym);
+	      parse_token_decl (nterm_sym);
 	      break;
 
 	    case tok_type:
@@ -1044,10 +917,6 @@ read_declarations (void)
 	      parse_expect_decl ();
 	      break;
 
-	    case tok_thong:
-	      parse_thong_decl ();
-	      break;
-
 	    case tok_left:
 	      parse_assoc_decl (left_assoc);
 	      break;
@@ -1074,7 +943,7 @@ read_declarations (void)
 	    case tok_stropt:
 	    case tok_intopt:
 	    case tok_obsolete:
-	      abort ();
+	      assert (0);
 	      break;
 
 	    case tok_illegal:
@@ -1095,37 +964,37 @@ read_declarations (void)
     }
 }
 
-/*-------------------------------------------------------------------.
-| Assuming that a `{' has just been seen, copy everything up to the  |
-| 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.                 |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| Assuming that a `{' has just been seen, copy everything up to the |
+| matching `}' into ACTION_OBSTACK.                                 |
+|                                                                   |
+| RULE_LENGTH 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.  It is not the same as the rule->length in the case of mid |
+| rule actions.                                                     |
+|                                                                   |
+| This routine is used for actions.                                 |
+`------------------------------------------------------------------*/
 
 static void
-parse_braces (symbol_list *rule, int stack_offset)
+parse_action (symbol_list *rule, int rule_length)
 {
-  int c;
-  int count;
-
-  count = 1;
+  int count = 1;
+  rule->action_line = lineno;
   while (count > 0)
     {
+      int c;
       while ((c = getc (finput)) != '}')
 	switch (c)
 	  {
 	  case '\n':
-	    obstack_1grow (&action_obstack, c);
-	    lineno++;
+	    copy_character (&action_obstack, c);
+	    ++lineno;
 	    break;
 
 	  case '{':
-	    obstack_1grow (&action_obstack, c);
-	    count++;
+	    copy_character (&action_obstack, c);
+	    ++count;
 	    break;
 
 	  case '\'':
@@ -1138,54 +1007,29 @@ parse_braces (symbol_list *rule, int stack_offset)
 	    break;
 
 	  case '$':
-	    copy_dollar (finput, &action_obstack,
-			 rule, stack_offset);
+	    copy_dollar (finput, &action_obstack, rule, rule_length);
 	    break;
 
 	  case '@':
-	    copy_at (finput, &action_obstack,
-		     stack_offset);
+	    copy_at (finput, &action_obstack, rule_length);
 	    break;
 
 	  case EOF:
 	    fatal (_("unmatched %s"), "`{'");
 
 	  default:
-	    obstack_1grow (&action_obstack, c);
+	    copy_character (&action_obstack, c);
 	  }
 
       /* Above loop exits when C is '}'.  */
       if (--count)
-	{
-	  obstack_1grow (&action_obstack, c);
-	  c = getc (finput);
-	}
+	copy_character (&action_obstack, c);
     }
 
   obstack_1grow (&action_obstack, '\0');
-}
-
-
-static void
-parse_action (symbol_list *rule, int stack_offset)
-{
-  rule->action_line = lineno;
-  parse_braces (rule, stack_offset);
   rule->action = obstack_finish (&action_obstack);
 }
 
-
-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);
-}
-
 
 
 /*-------------------------------------------------------------------.
@@ -1193,20 +1037,20 @@ parse_guard (symbol_list *rule, int stack_offset)
 | with the user's names.                                             |
 `-------------------------------------------------------------------*/
 
-static bucket *
+static symbol_t *
 gensym (void)
 {
   /* Incremented for each generated symbol */
   static int gensym_count = 0;
   static char buf[256];
 
-  bucket *sym;
+  symbol_t *sym;
 
   sprintf (buf, "@%d", ++gensym_count);
   token_buffer = buf;
   sym = getsym (token_buffer);
   sym->class = nterm_sym;
-  sym->value = nvars++;
+  sym->number = nvars++;
   return sym;
 }
 
@@ -1217,8 +1061,8 @@ gensym (void)
 | null pointer instead of a symbol to terminate the rule.  The next  |
 | symbol is the lhs of the following rule.                           |
 |                                                                    |
-| All guards and actions are copied out to the appropriate files,    |
-| labelled by the rule number they apply to.                         |
+| All actions are copied out, labelled by the rule number they apply |
+| to.                                                                |
 |                                                                    |
 | Bison used to allow some %directives in the rules sections, but    |
 | this is no longer consider appropriate: (i) the documented grammar |
@@ -1232,10 +1076,9 @@ static void
 readgram (void)
 {
   token_t t;
-  bucket *lhs = NULL;
+  symbol_t *lhs = NULL;
   symbol_list *p = NULL;
   symbol_list *p1 = NULL;
-  bucket *bp;
 
   /* Points to first symbol_list of current rule. its symbol is the
      lhs of the rule.  */
@@ -1252,7 +1095,7 @@ readgram (void)
 	/* Number of symbols in rhs of this rule so far */
 	int rulelength = 0;
 	int xactions = 0;	/* JF for error checking */
-	bucket *first_rhs = 0;
+	symbol_t *first_rhs = 0;
 
 	if (t == tok_identifier)
 	  {
@@ -1260,7 +1103,7 @@ readgram (void)
 
 	    if (!start_flag)
 	      {
-		startval = lhs;
+		startsymbol = lhs;
 		start_flag = 1;
 	      }
 
@@ -1279,8 +1122,8 @@ readgram (void)
 	  }
 	/* start a new rule and record its lhs.  */
 
-	nrules++;
-	nitems++;
+	++nrules;
+	++nritems;
 
 	p = symbol_list_new (lhs);
 
@@ -1298,8 +1141,8 @@ readgram (void)
 	if (lhs->class == unknown_sym)
 	  {
 	    lhs->class = nterm_sym;
-	    lhs->value = nvars;
-	    nvars++;
+	    lhs->number = nvars;
+	    ++nvars;
 	  }
 	else if (lhs->class == token_sym)
 	  complain (_("rule given for %s, which is a token"), lhs->tag);
@@ -1323,7 +1166,7 @@ readgram (void)
 	       If one does, exit this rule now.  */
 	    if (t == tok_identifier)
 	      {
-		bucket *ssave;
+		symbol_t *ssave;
 		token_t t1;
 
 		ssave = symval;
@@ -1331,7 +1174,10 @@ readgram (void)
 		unlex (t1);
 		symval = ssave;
 		if (t1 == tok_colon)
-		  break;
+		  {
+		    warn (_("previous rule lacks an ending `;'"));
+		    break;
+		  }
 
 		if (!first_rhs)	/* JF */
 		  first_rhs = symval;
@@ -1349,16 +1195,21 @@ readgram (void)
 		   inserting the new rule before it.  */
 
 		/* Make a dummy nonterminal, a gensym.  */
-		bucket *sdummy = gensym ();
+		symbol_t *sdummy = gensym ();
 
 		/* Make a new rule, whose body is empty, before the
 		   current one, so that the action just read can
 		   belong to it.  */
-		nrules++;
-		nitems++;
+		++nrules;
+		++nritems;
 		p = symbol_list_new (sdummy);
 		/* Attach its lineno to that of the host rule. */
 		p->line = crule->line;
+		/* Move the action from the host rule to this one. */
+		p->action = crule->action;
+		p->action_line = crule->action_line;
+		crule->action = NULL;
+
 		if (crule1)
 		  crule1->next = p;
 		else
@@ -1371,7 +1222,7 @@ readgram (void)
 
 		/* Insert the dummy generated by that rule into this
 		   rule.  */
-		nitems++;
+		++nritems;
 		p = symbol_list_new (sdummy);
 		p1->next = p;
 		p1 = p;
@@ -1381,7 +1232,7 @@ readgram (void)
 
 	    if (t == tok_identifier)
 	      {
-		nitems++;
+		++nritems;
 		p = symbol_list_new (symval);
 		p1->next = p;
 		p1 = p;
@@ -1390,9 +1241,9 @@ readgram (void)
 	      {
 		parse_action (crule, rulelength);
 		action_flag = 1;
-		xactions++;	/* JF */
+		++xactions;	/* JF */
 	      }
-	    rulelength++;
+	    ++rulelength;
 	  }			/* end of  read rhs of rule */
 
 	/* Put an empty link in the list to mark the end of this rule  */
@@ -1408,15 +1259,6 @@ readgram (void)
 	    t = lex ();
 	  }
 
-	if (t == tok_guard)
-	  {
-	    if (!semantic_parser)
-	      complain (_("%%guard present but %%semantic_parser not specified"));
-
-	    parse_guard (crule, rulelength);
-	    t = lex ();
-	  }
-
 	if (t == tok_left_curly)
 	  {
 	    /* This case never occurs -wjh */
@@ -1424,7 +1266,7 @@ readgram (void)
 	      complain (_("two actions at end of one rule"));
 	    parse_action (crule, rulelength);
 	    action_flag = 1;
-	    xactions++;	/* -wjh */
+	    ++xactions;	/* -wjh */
 	    t = lex ();
 	  }
 	/* If $$ is being set in default way, report if any type
@@ -1442,6 +1284,8 @@ readgram (void)
 	/* Warn if there is no default for $$ but we need one.  */
 	else if (!xactions && !first_rhs && lhs->type_name != 0)
 	  complain (_("empty rule for typed nonterminal, and no action"));
+	if (t == tok_two_percents || t == tok_eof)
+	  warn (_("previous rule lacks an ending `;'"));
 	if (t == tok_semicolon)
 	  t = lex ();
       }
@@ -1457,16 +1301,7 @@ readgram (void)
     fatal (_("no rules in the input grammar"));
 
   /* Report any undefined symbols and consider them nonterminals.  */
-
-  for (bp = firstsymbol; bp; bp = bp->next)
-    if (bp->class == unknown_sym)
-      {
-	complain (_
-		  ("symbol %s is used, but is not defined as a token and has no rules"),
-		  bp->tag);
-	bp->class = nterm_sym;
-	bp->value = nvars++;
-      }
+  symbols_check_defined ();
 
   /* Insert the initial rule, which line is that of the first rule
      (not that of the start symbol):
@@ -1474,20 +1309,19 @@ readgram (void)
      axiom: %start EOF.  */
   p = symbol_list_new (axiom);
   p->line = grammar->line;
-  p->next = symbol_list_new (startval);
+  p->next = symbol_list_new (startsymbol);
   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;
+  nritems += 3;
   grammar = p;
-  startval = axiom;
 
-  if (nsyms > MAXSHORT)
+  if (nsyms > SHRT_MAX)
     fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
-	   MAXSHORT);
+	   SHRT_MAX);
 
-  ntokens = nsyms - nvars;
+  assert (nsyms == ntokens + nvars);
 }
 
 /* At the end of the grammar file, some C source code must
@@ -1496,7 +1330,7 @@ readgram (void)
 static void
 read_additionnal_code (void)
 {
-  char c;
+  int c;
   struct obstack el_obstack;
 
   obstack_init (&el_obstack);
@@ -1509,227 +1343,27 @@ read_additionnal_code (void)
     }
 
   while ((c = getc (finput)) != EOF)
-    obstack_1grow (&el_obstack, c);
+    copy_character (&el_obstack, c);
 
   obstack_1grow (&el_obstack, 0);
   muscle_insert ("epilogue", obstack_finish (&el_obstack));
 }
 
 
-/*------------------------------------------------------------------.
-| Set TOKEN_TRANSLATIONS.  Check that no two symbols share the same |
-| number.                                                           |
-`------------------------------------------------------------------*/
-
-static void
-token_translations_init (void)
-{
-  bucket *bp = NULL;
-  int i;
-
-  token_translations = XCALLOC (short, max_user_token_number + 1);
-
-  /* Initialize all entries for literal tokens to 2, the internal
-     token number for $undefined., which represents all invalid
-     inputs.  */
-  for (i = 0; i <= max_user_token_number; i++)
-    token_translations[i] = 2;
-
-  for (bp = firstsymbol; bp; bp = bp->next)
-    {
-      /* Non-terminal? */
-      if (bp->value >= ntokens)
-	continue;
-      /* A token string alias? */
-      if (bp->user_token_number == SALIAS)
-	continue;
-
-      assert (bp->user_token_number != SUNDEF);
-
-      /* 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]],
-		  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 SYMBOL_TABLE, TAGS of symbols.        |
-`----------------------------------------------------------------*/
-
-static void
-packsymbols (void)
-{
-  bucket *bp = NULL;
-  int tokno = 1;
-  int last_user_token_number;
-
-  tags = XCALLOC (char *, nsyms + 1);
-  user_toknums = XCALLOC (short, nsyms + 1);
-  symbols = XCALLOC (bucket *, nsyms);
-
-  sassoc = XCALLOC (short, nsyms);
-
-  max_user_token_number = 256;
-  last_user_token_number = 256;
-
-  for (bp = firstsymbol; bp; bp = bp->next)
-    {
-      if (bp->class == nterm_sym)
-	{
-	  bp->value += ntokens;
-	}
-      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 == -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 != 0 && bp->alias->prec != 0
-		  && bp->user_token_number == SALIAS)
-		complain (_("conflicting precedences for %s and %s"),
-			  bp->tag, bp->alias->tag);
-	      if (bp->prec != 0)
-		bp->alias->prec = bp->prec;
-	      else
-		bp->prec = bp->alias->prec;
-	    }
-
-	  if (bp->assoc != bp->alias->assoc)
-	    {
-	      if (bp->assoc != 0 && bp->alias->assoc != 0
-		  && bp->user_token_number == SALIAS)
-		complain (_("conflicting assoc values for %s and %s"),
-			  bp->tag, bp->alias->tag);
-	      if (bp->assoc != 0)
-		bp->alias->assoc = bp->assoc;
-	      else
-		bp->assoc = bp->alias->assoc;
-	    }
-
-	  /* Do not do processing below for SALIASs.  */
-	  if (bp->user_token_number == SALIAS)
-	    continue;
-
-	}
-      else /* bp->class == token_sym */
-	{
-	  if (bp == eoftoken)
-	    bp->value = 0;
-	  else
-	    bp->value = tokno++;
-	}
-
-      if (bp->class == token_sym)
-	{
-	  if (bp->user_token_number == SUNDEF)
-	    bp->user_token_number = ++last_user_token_number;
-	  if (bp->user_token_number > max_user_token_number)
-	    max_user_token_number = bp->user_token_number;
-	}
-
-      symbols[bp->value] = bp;
-      tags[bp->value] = bp->tag;
-      user_toknums[bp->value] = bp->user_token_number;
-      sassoc[bp->value] = bp->assoc;
-    }
-
-  token_translations_init ();
-
-  error_token_number = errtoken->value;
-
-  if (startval->class == unknown_sym)
-    fatal (_("the start symbol %s is undefined"), startval->tag);
-  else if (startval->class == token_sym)
-    fatal (_("the start symbol %s is a token"), startval->tag);
-
-  start_symbol = startval->value;
-}
-
-
-/*---------------------------------------------------------------.
-| Save the definition of token names in the `TOKENDEFS' muscle.  |
-`---------------------------------------------------------------*/
-
-static void
-symbols_save (void)
-{
-  struct obstack tokendefs;
-  bucket *bp;
-  obstack_init (&tokendefs);
-
-  for (bp = firstsymbol; bp; bp = bp->next)
-    {
-      char *symbol = bp->tag;                /* get symbol */
-
-      if (bp->value >= ntokens)
-	continue;
-      if (bp->user_token_number == SALIAS)
-	continue;
-      if ('\'' == *symbol)
-	continue;               /* skip literal character */
-      if (bp == errtoken)
-	continue;               /* skip error token */
-      if ('\"' == *symbol)
-	{
-	  /* use literal string only if given a symbol with an alias */
-	  if (bp->alias)
-	    symbol = bp->alias->tag;
-	  else
-	    continue;
-	}
-
-      /* Don't #define nonliteral tokens whose names contain periods.  */
-      if (strchr (symbol, '.'))
-	continue;
-
-      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.  */
-	obstack_fgrow2 (&tokendefs, "# define T%s\t%d\n", symbol, bp->value);
-    }
-
-  obstack_1grow (&tokendefs, 0);
-  muscle_insert ("tokendef", xstrdup (obstack_finish (&tokendefs)));
-  obstack_free (&tokendefs, NULL);
-}
-
-
 /*---------------------------------------------------------------.
 | Convert the rules into the representation using RRHS, RLHS and |
-| RITEMS.                                                        |
+| RITEM.                                                         |
 `---------------------------------------------------------------*/
 
 static void
 packgram (void)
 {
-  int itemno;
+  unsigned int itemno;
   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);
-  rule_table = XCALLOC (rule_t, nrules) - 1;
+  ritem = XCALLOC (item_number_t, nritems);
+  rules = XCALLOC (rule_t, nrules) - 1;
 
   itemno = 0;
   ruleno = 1;
@@ -1737,27 +1371,26 @@ packgram (void)
   p = grammar;
   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;
-      rule_table[ruleno].guard = p->guard;
-      rule_table[ruleno].guard_line = p->guard_line;
+      symbol_t *ruleprec = p->ruleprec;
+      rules[ruleno].user_number = ruleno;
+      rules[ruleno].number = ruleno;
+      rules[ruleno].lhs = p->sym;
+      rules[ruleno].rhs = ritem + itemno;
+      rules[ruleno].line = p->line;
+      rules[ruleno].useful = TRUE;
+      rules[ruleno].action = p->action;
+      rules[ruleno].action_line = p->action_line;
 
       p = p->next;
       while (p && p->sym)
 	{
-	  ritem[itemno++] = p->sym->value;
+	  /* item_number_t = symbol_number_t.
+	     But the former needs to contain more: negative rule numbers. */
+	  ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
 	  /* A rule gets by default the precedence and associativity
 	     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;
 	  if (p)
 	    p = p->next;
 	}
@@ -1766,53 +1399,32 @@ packgram (void)
          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].precsym = ruleprec;
+	  rules[ruleno].prec = ruleprec;
 	}
-
       ritem[itemno++] = -ruleno;
-      ruleno++;
+      ++ruleno;
 
       if (p)
 	p = p->next;
     }
 
-  ritem[itemno] = 0;
-  nritems = itemno;
-  assert (nritems == nitems);
+  assert (itemno == nritems);
 
   if (trace_flag)
     ritem_print (stderr);
 }
 
-/*-------------------------------------------------------------------.
-| Read in the grammar specification and record it in the format      |
-| described in gram.h.  All guards are copied into the GUARD_OBSTACK |
-| and all actions into ACTION_OBSTACK, in each case forming the body |
-| of a C function (YYGUARD or YYACTION) which contains a switch      |
-| statement to decide which guard or action to execute.              |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| Read in the grammar specification and record it in the format     |
+| described in gram.h.  All actions are copied into ACTION_OBSTACK, |
+| in each case forming the body of a C function (YYACTION) which    |
+| contains a switch statement to decide which action to execute.    |
+`------------------------------------------------------------------*/
 
 void
 reader (void)
 {
-  start_flag = 0;
-  startval = NULL;		/* start symbol not specified yet. */
-
-  nsyms = 0;
-  nvars = 0;
-  nrules = 0;
-  nitems = 0;
-
-  typed = 0;
-  lastprec = 0;
-
-  semantic_parser = 0;
-  pure_parser = 0;
-
-  grammar = NULL;
-
   lex_init ();
   lineno = 1;
 
@@ -1820,28 +1432,29 @@ reader (void)
   obstack_init (&muscle_obstack);
 
   /* Initialize the symbol table.  */
-  tabinit ();
+  symbols_new ();
 
   /* Construct the axiom symbol. */
   axiom = getsym ("$axiom");
   axiom->class = nterm_sym;
-  axiom->value = nvars++;
+  axiom->number = nvars++;
 
   /* Construct the error token */
   errtoken = getsym ("error");
   errtoken->class = token_sym;
-  errtoken->user_token_number = 256;	/* Value specified by POSIX.  */
+  errtoken->number = ntokens++;
 
   /* Construct a token that represents all undefined literal tokens.
      It is always token number 2.  */
   undeftoken = getsym ("$undefined.");
   undeftoken->class = token_sym;
-  undeftoken->user_token_number = 2;
+  undeftoken->number = ntokens++;
 
   /* Initialize the obstacks. */
   obstack_init (&action_obstack);
-  obstack_init (&attrs_obstack);
   obstack_init (&output_obstack);
+  obstack_init (&pre_prologue_obstack);
+  obstack_init (&post_prologue_obstack);
 
   finput = xfopen (infile, "r");
 
@@ -1855,12 +1468,13 @@ reader (void)
     {
       eoftoken = getsym ("$");
       eoftoken->class = token_sym;
+      eoftoken->number = 0;
       /* Value specified by POSIX.  */
       eoftoken->user_token_number = 0;
     }
 
   /* Read in the grammar, build grammar in list form.  Write out
-     guards and actions.  */
+     actions.  */
   readgram ();
   /* Some C code is given at the end of the grammar file. */
   read_additionnal_code ();
@@ -1870,10 +1484,11 @@ reader (void)
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */
-  packsymbols ();
-  /* Save them. */
-  symbols_save ();
+  symbols_pack ();
 
   /* Convert the grammar into the format described in gram.h.  */
   packgram ();
+
+  /* The grammar as a symbol_list is no longer needed. */
+  LIST_FREE (symbol_list, grammar);
 }