On Mon, Sep 18, 2006 at 10:34:39AM -0700, Paul Eggert wrote:
> Bob Rossi <[EMAIL PROTECTED]> writes:
>
> >> Why the #ifdef on YYLTYPE_IS_TRIVIAL? YYLTYPE_IS_TRIVIAL tells
> >> us whether yyltype is trivial (i.e., does not need attention by
> >> C++ storage managers), not whether it exists.
> >
> > OK, I need to determine if YYLTYPE is exists. What's the best way
> > to do that?
>
> b4_locations_if.
>
> >> status = yypushparse (ctx, ch, yylval, yylloc);
> > ...
> > I'm not sure that I like passing all the values into yypushparse though.
> > The problem is, not everyone wants to pass all the values in. We would
> > force them to pass values in that they don't care about which could
> > be confusing.
>
> They always need to pass in ctx, ch, right? And the ", yylloc"
> will be required if b4_locations_if says you're using locations.
> So the only questionable argument will be yylval.
>
> One way to address this issue would be to have two entry points:
>
> status = yypushparse (ctx, ch, yylloc);
>
> for tokens that have no semantic value, and
>
> status = yypushparseval (ctx, ch, yylval, yylloc);
>
> for tokens that do.
>
> Another possibility, which will avoid a copy in some cases if semantic
> values are large, is to pass a pointer:
>
> status = yypushparse (ctx, ch, &yylval, yylloc);
>
> where you pass a NULL pointer if the token has no semantic value. If
> the copying issue is of concern, it may also make sense to pass yylloc's
> address too:
>
> status = yypushparse (ctx, ch, &yylval, &yylloc);
>
> I don't know whether the copying concern is enough to affect
> performance, though.
I'm not decided on how to modify the yypushparse function parameters.
Have you made up your mind?
Attached is a patch on some changes we both agree on. That is remove the
constant 4 from the user and use YYPUSH_MORE. Also, make yypushparse
return an int, instead of void. This has the benefit of removing the
yyresult_get function.
2006-09-20 Bob Rossi <[EMAIL PROTECTED]>
* data/push.c (yyresult_get): Remove function.
(YYPUSH_MORE): Add #define.
(yypushparse): Modify return value.
Thanks,
Bob Rossi
Index: data/push.c
===================================================================
RCS file: /sources/bison/bison/data/push.c,v
retrieving revision 1.1
diff -u -r1.1 push.c
--- data/push.c 15 Sep 2006 15:56:26 -0000 1.1
+++ data/push.c 21 Sep 2006 02:11:17 -0000
@@ -162,7 +162,7 @@
#define yydebug b4_prefix[]debug
#define yynerrs b4_prefix[]nerrs
b4_locations_if([#define yylloc b4_prefix[]lloc])
-b4_push_if([#define yyresult_get b4_prefix[]result_get
+b4_push_if([
#define yychar_set b4_prefix[]char_set
#define yylval_set b4_prefix[]lval_set
#define yylloc_set b4_prefix[]lloc_set])])[
@@ -973,14 +973,14 @@
]b4_push_if([
struct yypvars;
-]b4_c_function_decl([yyresult_get], [int], [[struct yypvars *YYPVARS],
[YYPVARS]])[
+#define YYPUSH_MORE 4
]b4_c_function_decl([yychar_set], [void], [[struct yypvars *YYPVARS],
[YYPVARS]], [[int yychar], [yychar]])[
]b4_c_function_decl([yylval_set], [void], [[struct yypvars *YYPVARS],
[YYPVARS]], [[YYSTYPE yylval], [yylval]])[
#ifdef YYLTYPE_IS_TRIVIAL
]b4_c_function_decl([yylloc_set], [void], [[struct yypvars *YYPVARS],
[YYPVARS]], [[YYLTYPE yylloc], [yylloc]])[
#endif
]b4_c_function_decl([yypvarsinit], [void *], [[void], []])[
-]b4_c_function_decl([yypushparse], [void],
+]b4_c_function_decl([yypushparse], [int],
[[struct yypvars *YYPVARS], [YYPVARS]])[
])[
@@ -1103,12 +1103,6 @@
return (void*) pv;
}
-int
-yyresult_get (struct yypvars *YYPVARS)
-{
- return YYPVARS->yyresult;
-}
-
void
yychar_set (struct yypvars *YYPVARS, int yychar)
{
@@ -1143,7 +1137,7 @@
`-------------------------*/
b4_push_if([
-b4_c_function_def([yypushparse], [void], [[struct yypvars *YYPVARS],
[YYPVARS]])],[
+b4_c_function_def([yypushparse], [int], [[struct yypvars *YYPVARS],
[YYPVARS]])],[
#ifdef YYPARSE_PARAM
b4_c_function_def([yyparse], [int], [[void *YYPARSE_PARAM], [YYPARSE_PARAM]])
#else /* ! YYPARSE_PARAM */
@@ -1423,7 +1417,7 @@
pv->yylen = yylen;
pv->yyval = yyval;
]b4_locations_if([pv->yyloc = yyloc;])[
- return;
+ return yyresult;
gottoken:
YYDPRINTF((stderr, "Reading a token: "));],[
YYDPRINTF ((stderr, "Reading a token: "));
@@ -1717,10 +1711,9 @@
if (yymsg != yymsgbuf_ptr)
YYSTACK_FREE (yymsg);
#endif
- ]b4_push_if([pv->yyresult = YYID (yyresult);],[
+ ]b4_push_if([pv->yyresult = YYID (yyresult);])[
/* Make sure YYID is used. */
return YYID (yyresult);
- ])[
]}
b4_push_if([
@@ -1738,9 +1731,8 @@
#ifdef YYLTYPE_IS_TRIVIAL
yylloc_set (ctx, yylloc);
#endif
- yypushparse (ctx);
- status = yyresult_get (ctx);
- } while (status == 4);
+ status = yypushparse (ctx);
+ } while (status == YYPUSH_MORE);
free (ctx);
return status;
]}])
@@ -1788,7 +1780,8 @@
# define YYLTYPE_IS_TRIVIAL 1
#endif
-]b4_push_if([struct ]b4_prefix[pvars;])[
+]b4_push_if([struct ]b4_prefix[pvars;
+#define YYPUSH_MORE 4])[
]b4_pure_if([],
[extern YYLTYPE b4_prefix[]lloc;])
)dnl b4_locations_if
