Re: calc.at workaround for current test failures

[Paul Eggert]

> From: Frank Heckenbach <address@hidden>
> Date: Fri, 20 Jun 2003 00:20:35 +0200

> In my copy it says (line 708):
> 
>       YYLLOC_DEFAULT (*yylocp, yyvsp - yyrhslen, yyrhslen);
> 
> It should be:
> 
>       YYLLOC_DEFAULT ((*yylocp), (yyvsp - yyrhslen), yyrhslen);
> 
> I suppose you mean the macro definition. Yes, generally, parentheses
> are put in macro definitions. But since in this case the macro call
> is generated by bison and the macro is (often) provided by the user,
> it might be useful to add the parentheses in the call.

I'd rather follow the usual convention, which is that it's the C
macro definition's responsibility for proper parenthesization.  So I
installed this patch:

2003-06-20  Paul Eggert  <address@hidden>

        * data/glr.c (YYLLOC_DEFAULT): Parenthesize arguments as needed,
        and return properly parenthesized result.
        * data/lalar1.cc (YYLLOC_DEFAULT): Likewise.
        * data/yacc.c (YYLLOC_DEFAULT): Likewise.
        Remove unnecessary parentheses from uses.
        * doc/bison.texinfo (Location Default Action): Describe the
        conventions for parentheses.

Index: data/glr.c
===================================================================
RCS file: /cvsroot/bison/bison/data/glr.c,v
retrieving revision 1.59
diff -p -u -r1.59 glr.c
--- data/glr.c  19 Jun 2003 08:45:16 -0000      1.59
+++ data/glr.c  20 Jun 2003 22:49:46 -0000
@@ -414,14 +414,14 @@ static const ]b4_int_type_for([b4_stos])
 
 #ifndef YYLLOC_DEFAULT
 # define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN)                 \
-  (yyCurrent).first_line   = YYRHSLOC(yyRhs,1).first_line;     \
-  (yyCurrent).first_column = YYRHSLOC(yyRhs,1).first_column;   \
-  (yyCurrent).last_line    = YYRHSLOC(yyRhs,YYN).last_line;    \
-  (yyCurrent).last_column  = YYRHSLOC(yyRhs,YYN).last_column;
+   ((yyCurrent).first_line = YYRHSLOC(yyRhs, 1).first_line,    \
+    (yyCurrent).first_column = YYRHSLOC(yyRhs, 1).first_column,        \
+    (yyCurrent).last_line = YYRHSLOC(yyRhs, YYN).last_line,    \
+    (yyCurrent).last_column  = YYRHSLOC(yyRhs, YYN).last_column)
 #endif
 ]],[
 #ifndef YYLLOC_DEFAULT
-# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN)
+# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN) ((void) 0)
 #endif
 ])[
 
Index: data/lalr1.cc
===================================================================
RCS file: /cvsroot/bison/bison/data/lalr1.cc,v
retrieving revision 1.34
diff -p -u -r1.34 lalr1.cc
--- data/lalr1.cc       4 Jun 2003 05:53:10 -0000       1.34
+++ data/lalr1.cc       20 Jun 2003 22:49:47 -0000
@@ -170,7 +170,7 @@ b4_syncline(address@hidden@], address@hidden@])],
 b4_syncline(address@hidden@], address@hidden@])[
 #ifndef YYLLOC_DEFAULT
 # define YYLLOC_DEFAULT(Current, Rhs, N) \
-   Current.end = Rhs[N].end;
+   ((Current).end = Rhs[N].end)
 #endif
 
 namespace yy
Index: data/yacc.c
===================================================================
RCS file: /cvsroot/bison/bison/data/yacc.c,v
retrieving revision 1.58
diff -p -u -r1.58 yacc.c
--- data/yacc.c 2 Jun 2003 03:57:39 -0000       1.58
+++ data/yacc.c 20 Jun 2003 22:49:48 -0000
@@ -501,11 +501,11 @@ while (0)
    are run).  */
 
 #ifndef YYLLOC_DEFAULT
-# define YYLLOC_DEFAULT(Current, Rhs, N)         \
-  Current.first_line   = Rhs[1].first_line;      \
-  Current.first_column = Rhs[1].first_column;    \
-  Current.last_line    = Rhs[N].last_line;       \
-  Current.last_column  = Rhs[N].last_column;
+# define YYLLOC_DEFAULT(Current, Rhs, N)               \
+   ((Current).first_line   = (Rhs)[1].first_line,      \
+    (Current).first_column = (Rhs)[1].first_column,    \
+    (Current).last_line    = (Rhs)[N].last_line,       \
+    (Current).last_column  = (Rhs)[N].last_column)
 #endif
 
 /* YYLEX -- calling `yylex' with the right arguments.  */
@@ -983,7 +983,7 @@ yyreduce:
 
 ]b4_location_if(
 [  /* Default location. */
-  YYLLOC_DEFAULT (yyloc, (yylsp - yylen), yylen);])[
+  YYLLOC_DEFAULT (yyloc, yylsp - yylen, yylen);])[
   YY_REDUCE_PRINT (yyn);
   switch (yyn)
     ]{
@@ -1180,7 +1180,7 @@ yyerrlab1:
   YYDPRINTF ((stderr, "Shifting error token, "));
 
   *++yyvsp = yylval;
-]b4_location_if([  YYLLOC_DEFAULT (yyloc, yylsp, (yylerrsp - yylsp));
+]b4_location_if([  YYLLOC_DEFAULT (yyloc, yylsp, yylerrsp - yylsp);
   *++yylsp = yyloc;])[
 
   yystate = yyn;
Index: doc/bison.texinfo
===================================================================
RCS file: /cvsroot/bison/bison/doc/bison.texinfo,v
retrieving revision 1.109
diff -p -u -r1.109 bison.texinfo
--- doc/bison.texinfo   17 Jun 2003 05:15:49 -0000      1.109
+++ doc/bison.texinfo   20 Jun 2003 22:49:56 -0000
@@ -3210,11 +3210,11 @@ By default, @code{YYLLOC_DEFAULT} is def
 
 @example
 @group
-#define YYLLOC_DEFAULT(Current, Rhs, N)          \
-  Current.first_line   = Rhs[1].first_line;      \
-  Current.first_column = Rhs[1].first_column;    \
-  Current.last_line    = Rhs[N].last_line;       \
-  Current.last_column  = Rhs[N].last_column;
+# define YYLLOC_DEFAULT(Current, Rhs, N)               \
+   ((Current).first_line   = (Rhs)[1].first_line,      \
+    (Current).first_column = (Rhs)[1].first_column,    \
+    (Current).last_line    = (Rhs)[N].last_line,       \
+    (Current).last_column  = (Rhs)[N].last_column)
 @end group
 @end example
 
@@ -3223,11 +3223,11 @@ and like this for @acronym{GLR} parsers:
 
 @example
 @group
-#define YYLLOC_DEFAULT(Current, Rhs, N)          \
-  Current.first_line   = YYRHSLOC(Rhs,1).first_line;      \
-  Current.first_column = YYRHSLOC(Rhs,1).first_column;    \
-  Current.last_line    = YYRHSLOC(Rhs,N).last_line;       \
-  Current.last_column  = YYRHSLOC(Rhs,N).last_column;
+# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN)                 \
+   ((yyCurrent).first_line = YYRHSLOC(yyRhs, 1).first_line,    \
+    (yyCurrent).first_column = YYRHSLOC(yyRhs, 1).first_column,        \
+    (yyCurrent).last_line = YYRHSLOC(yyRhs, YYN).last_line,    \
+    (yyCurrent).last_column  = YYRHSLOC(yyRhs, YYN).last_column)
 @end group
 @end example
 
@@ -3241,6 +3241,12 @@ result) should be modified by @code{YYLL
 @item
 For consistency with semantic actions, valid indexes for the location
 array range from 1 to @var{n}.
+
address@hidden
+Your macro should parenthesize its arguments, if need be, since the
+actual arguments may not be surrounded by parentheses.  Also, your
+macro should expand to something that can be used as a single
+statement when it is followed by a semicolon.
 @end itemize
 
 @node Declarations