(YYERROR): Now just 'goto yyerrorlab', since the

macro's size was becoming unwieldy.
(yyerrlab): Do not discard an empty lookahead symbol, as this
might destroy garbage.
(yyerrorlab): New label, with the old contents of YYERROR,
plus the following change: pop the stack of rhs corresponding
to the production that invoked YYERROR.  That is how Yacc
behaves, and POSIX requires this behavior.
(yyerrlab1): Use YYPOPSTACK instead of its definiens.

diff --git a/data/yacc.c b/data/yacc.c
index 359a900..1af5ec0 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -466,14 +466,7 @@ static const ]b4_int_type_for([b4_stos])[ yystos[] =
 
 #define YYACCEPT       goto yyacceptlab
 #define YYABORT                goto yyabortlab
-#define YYERROR                ]b4_location_if([do                             \
-                         {                             \
-                           yylerrsp = yylsp;           \
-                           *++yylerrsp = yyloc;        \
-                           goto yyerrlab1;             \
-                         }                             \
-                       while (0)],
-                       [goto yyerrlab1])[
+#define YYERROR                goto yyerrorlab
 
 
 /* Like YYERROR except do call yyerror.  This remains here temporarily
@@ -1101,25 +1094,27 @@ yyerrlab:
       /* If just tried and failed to reuse lookahead token after an
         error, discard it.  */
 
-      /* Return failure if at end of input.  */
-      if (yychar == YYEOF)
+      if (yychar <= YYEOF)
         {
-         /* Pop the error token.  */
-          YYPOPSTACK;
-         /* Pop the rest of the stack.  */
-         while (yyss < yyssp)
-           {
-             YYDSYMPRINTF ("Error: popping", yystos[*yyssp], yyvsp, yylsp);
-             yydestruct (yystos[*yyssp], yyvsp]b4_location_if([, yylsp])[);
-             YYPOPSTACK;
-           }
-         YYABORT;
+          /* If at end of input, pop the error token,
+            then the rest of the stack, then return failure.  */
+         if (yychar == YYEOF)
+            for (;;)
+              {
+                YYPOPSTACK;
+                if (yyssp == yyss)
+                  YYABORT;
+                YYDSYMPRINTF ("Error: popping", yystos[*yyssp], yyvsp, yylsp);
+                yydestruct (yystos[*yyssp], yyvsp]b4_location_if([, yylsp])[);
+              }
         }
-
-      YYDSYMPRINTF ("Error: discarding", yytoken, &yylval, &yylloc);
-      yydestruct (yytoken, &yylval]b4_location_if([, &yylloc])[);
-      yychar = YYEMPTY;
-]b4_location_if([      *++yylerrsp = yylloc;])[
+      else
+       {
+         YYDSYMPRINTF ("Error: discarding", yytoken, &yylval, &yylloc);
+         yydestruct (yytoken, &yylval]b4_location_if([, &yylloc])[);
+         yychar = YYEMPTY;
+]b4_location_if([        *++yylerrsp = yylloc;])[
+       }
     }
 
   /* Else will try to reuse lookahead token after shifting the error
@@ -1127,9 +1122,30 @@ yyerrlab:
   goto yyerrlab1;
 
 
-/*----------------------------------------------------.
-| yyerrlab1 -- error raised explicitly by an action.  |
-`----------------------------------------------------*/
+/*---------------------------------------------------.
+| yyerrorlab -- error raised explicitly by YYERROR.  |
+`---------------------------------------------------*/
+yyerrorlab:
+
+#ifdef __GNUC__
+  /* Pacify GCC when the user code never invokes YYERROR and the label
+     yyerrorlab therefore never appears in user code.  */
+  if (0)
+     goto yyerrorlab;
+#endif
+
+  yyvsp -= yylen;
+  yyssp -= yylen;
+  yystate = *yyssp;
+  ]b4_location_if([yylerrsp = yylsp;
+  *++yylerrsp = yyloc;
+  yylsp -= yylen;
+  ])[goto yyerrlab1;
+
+
+/*-------------------------------------------------------------.
+| yyerrlab1 -- common code for both syntax error and YYERROR.  |
+`-------------------------------------------------------------*/
 yyerrlab1:
   yyerrstatus = 3;     /* Each real token shifted decrements this.  */
 
@@ -1153,9 +1169,8 @@ yyerrlab1:
 
       YYDSYMPRINTF ("Error: popping", yystos[*yyssp], yyvsp, yylsp);
       yydestruct (yystos[yystate], yyvsp]b4_location_if([, yylsp])[);
-      yyvsp--;
-      yystate = *--yyssp;
-]b4_location_if([      yylsp--;])[
+      YYPOPSTACK;
+      yystate = *yyssp;
       YY_STACK_PRINT (yyss, yyssp);
     }