Some code and documentation improvements.

[bison.git] / data / yacc.c

diff --git a/data/yacc.c b/data/yacc.c
index 5e737b761be34612b8c2f0aa1b13d94692f9bb73..56e662d634eab2a12cba8ea33a2d495f4bcf7350 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -586,6 +586,12 @@ static const ]b4_int_type_for([b4_table])[ yytable[] =
   ]b4_table[
 };
 
+#define yyis_pact_ninf(yystate) \
+  ]b4_table_value_equals([[pact]], [[yystate]], [b4_pact_ninf])[
+
+#define yyis_table_ninf(yytable_value) \
+  ]b4_table_value_equals([[table]], [[yytable_value]], [b4_table_ninf])[
+
 static const ]b4_int_type_for([b4_check])[ yycheck[] =
 {
   ]b4_check[
@@ -934,7 +940,8 @@ yysyntax_error (char *yyresult, int yystate, int yychar)
       char const *yyprefix = yyexpecting;
 
       /* Start YYX at -YYN if negative to avoid negative indexes in
-        YYCHECK.  */
+        YYCHECK.  In other words, skip the first -YYN actions for this
+        state because they are default actions.  */
       int yyxbegin = yyn < 0 ? -yyn : 0;
 
       /* Stay within bounds of both yycheck and yytname.  */
@@ -1347,7 +1354,7 @@ yybackup:
 
   /* First try to decide what to do without reference to lookahead token.  */
   yyn = yypact[yystate];
-  if (yyn == YYPACT_NINF)
+  if (yyis_pact_ninf (yyn))
     goto yydefault;
 
   /* Not known => get a lookahead token if don't already have one.  */
@@ -1397,7 +1404,7 @@ yyread_pushed_token:]])[
   yyn = yytable[yyn];
   if (yyn <= 0)
     {
-      if (yyn == 0 || yyn == YYTABLE_NINF)
+      if (yyn == 0 || yyis_table_ninf (yyn))
        goto yyerrlab;
       yyn = -yyn;
       goto yyreduce;
@@ -1581,7 +1588,7 @@ yyerrlab1:
   for (;;)
     {
       yyn = yypact[yystate];
-      if (yyn != YYPACT_NINF)
+      if (!yyis_pact_ninf (yyn))
        {
          yyn += YYTERROR;
          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYTERROR)