Actually handle the yytable zero value correctly this time.

* data/bison.m4 (b4_integral_parser_tables_map): Don't mention
zero values in the YYTABLE comments.
* data/glr.c (yytable_value_is_error): Don't check for zero
value.
* data/lalr1.cc (yy_table_value_is_error_): Likewise.
* data/yacc.c (yytable_value_is_error): Likewise.
* data/lalr1.java (yy_table_value_is_error_): Likewise.
(yysyntax_error): Fix typo in code: use yytable_ not yycheck_.
* src/tables.h: In header comments, explain why it's useless to
check for a zero value in yytable.

ChangeLog

@@ -1,3 +1,17 @@
+2009-08-26  Joel E. Denny  <jdenny@clemson.edu>
+
+	Actually handle the yytable zero value correctly this time.
+	* data/bison.m4 (b4_integral_parser_tables_map): Don't mention
+	zero values in the YYTABLE comments.
+	* data/glr.c (yytable_value_is_error): Don't check for zero
+	value.
+	* data/lalr1.cc (yy_table_value_is_error_): Likewise.
+	* data/yacc.c (yytable_value_is_error): Likewise.
+	* data/lalr1.java (yy_table_value_is_error_): Likewise.
+	(yysyntax_error): Fix typo in code: use yytable_ not yycheck_.
+	* src/tables.h: In header comments, explain why it's useless to
+	check for a zero value in yytable.
+
 2009-08-25  Joel E. Denny  <jdenny@clemson.edu>
 
 	More fixes related to last two patches.

data/bison.m4

@@ -266,7 +266,7 @@ $1([defgoto], [b4_defgoto], [[YYDEFGOTO[NTERM-NUM].]])
 $1([table], [b4_table],
    [[YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
 positive, shift that token.  If negative, reduce the rule which
-number is the opposite.  If zero or YYTABLE_NINF, syntax error.]])
+number is the opposite.  If YYTABLE_NINF, syntax error.]])
 
 $1([check], [b4_check])
 

data/glr.c

@@ -972,8 +972,7 @@ yydefaultAction (yyStateNum yystate)
 }
 
 #define yytable_value_is_error(yytable_value) \
-  (]b4_table_value_equals([[table]], [[yytable_value]], [b4_table_ninf])[ \
+  ]b4_table_value_equals([[table]], [[yytable_value]], [b4_table_ninf])[
-   || ]b4_table_value_equals([[table]], [[yytable_value]], [[0]])[)
 
 /** Set *YYACTION to the action to take in YYSTATE on seeing YYTOKEN.
  *  Result R means

data/lalr1.cc

@@ -668,7 +668,7 @@ b4_percent_code_get[]dnl
   inline bool
   ]b4_parser_class_name[::yy_table_value_is_error_ (int yyvalue)
   {
-    return yyvalue == 0 || yyvalue == yytable_ninf_;
+    return yyvalue == yytable_ninf_;
   }
 
   int

data/lalr1.java

@@ -745,7 +745,7 @@ m4_popdef([b4_at_dollar])])dnl
             int count = 0;
             for (int x = yyxbegin; x < yyxend; ++x)
               if (yycheck_[x + yyn] == x && x != yyterror_
-                  && !yy_table_value_is_error_ (yycheck_[x + yyn]))
+                  && !yy_table_value_is_error_ (yytable_[x + yyn]))
                 ++count;
 
             // FIXME: This method of building the message is not compatible
@@ -757,7 +757,7 @@ m4_popdef([b4_at_dollar])])dnl
                 count = 0;
                 for (int x = yyxbegin; x < yyxend; ++x)
                   if (yycheck_[x + yyn] == x && x != yyterror_
-                      && !yy_table_value_is_error_ (yycheck_[x + yyn]))
+                      && !yy_table_value_is_error_ (yytable_[x + yyn]))
                     {
                       res.append (count++ == 0 ? ", expecting " : " or ");
                       res.append (yytnamerr_ (yytname_[x]));
@@ -785,7 +785,7 @@ m4_popdef([b4_at_dollar])])dnl
    */
   private static boolean yy_table_value_is_error_ (int yyvalue)
   {
-    return yyvalue == 0 || yyvalue == yytable_ninf_;
+    return yyvalue == yytable_ninf_;
   }
 
   private static final ]b4_int_type_for([b4_pact])[ yypact_ninf_ = ]b4_pact_ninf[;

data/yacc.c

@@ -531,8 +531,7 @@ static const ]b4_int_type_for([b4_toknum])[ yytoknum[] =
 #define YYTABLE_NINF ]b4_table_ninf[
 
 #define yytable_value_is_error(yytable_value) \
-  (]b4_table_value_equals([[table]], [[yytable_value]], [b4_table_ninf])[ \
+  ]b4_table_value_equals([[table]], [[yytable_value]], [b4_table_ninf])[
-  || ]b4_table_value_equals([[table]], [[yytable_value]], [[0]])[)
 
 ]b4_parser_tables_define[
 

src/parse-gram.h

@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 2.4.388-53f03.  */
+/* A Bison parser, made by GNU Bison 2.4.390-0aaa.  */
 
 /* Interface for Bison's Yacc-like parsers in C
 
@@ -157,7 +157,7 @@
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
 typedef union YYSTYPE
 {
-/* Line 1609 of yacc.c  */
+/* Line 1608 of yacc.c  */
 #line 94 "parse-gram.y"
 
   symbol *symbol;
@@ -171,7 +171,7 @@ typedef union YYSTYPE
   named_ref *named_ref;
 
 
-/* Line 1609 of yacc.c  */
+/* Line 1608 of yacc.c  */
 #line 176 "src/parse-gram.h"
 } YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1

src/tables.c

@@ -126,7 +126,7 @@ static int table_size = 32768;
 base_number *table;
 base_number *check;
 /* The value used in TABLE to denote explicit syntax errors
-   (%nonassoc), a negative infinite.  First defaults to ACTION_NUMBER_MININUM,
+   (%nonassoc), a negative infinite.  First defaults to ACTION_NUMBER_MINIMUM,
    but in order to keep small tables, renumbered as TABLE_ERROR, which
    is the smallest (non error) value minus 1.  */
 base_number table_ninf = 0;

src/tables.h

@@ -48,7 +48,7 @@
    YYFINAL = the state number of the termination state.
 
    YYTABLE = a vector filled with portions for different uses, found
-   via YYPACT and YYPGOTO.
+   via YYPACT and YYPGOTO, described below.
 
    YYLAST ( = high) the number of the last element of YYTABLE, i.e.,
    sizeof (YYTABLE) - 1.
@@ -87,7 +87,7 @@
 
    If the value is negative, it is minus a rule number to reduce by.
 
-   If the value is zero or YYTABLE_NINF, it's a syntax error.
+   If the value is YYTABLE_NINF, it's a syntax error.
 
    YYPGOTO[I] = the index in YYTABLE of the portion describing what to
    do after reducing a rule that derives variable I + NTOKENS.  This
@@ -99,6 +99,16 @@
    YYCHECK[YYPGOTO[I] + S] != S), then the default state (that is,
    YYDEFGOTO[I]) should be used instead of YYTABLE.  Otherwise,
    YYTABLE[YYPGOTO[I] + S] is the state to go to even if YYPGOTO[I] < 0.
+
+   When the above YYPACT, YYPGOTO, and YYCHECK tests determine that a
+   value from YYTABLE should be used, that value is never zero, so it is
+   useless to check for zero.  When those tests indicate that the value
+   from YYDEFACT or YYDEFGOTO should be used instead, the value from
+   YYTABLE *might* be zero, which, as a consequence of the way in which
+   the tables are constructed, also happens to indicate that YYDEFACT or
+   YYDEFGOTO should be used.  However, the YYTABLE value cannot be
+   trusted when the YYDEFACT or YYDEFGOTO value should be used.  In
+   summary, forget about zero values in YYTABLE.
 */
 
 extern int nvectors;