Re: Rule Line number for GLR C Parser

[Akim Demaille]

Hi Lars,

> Le 10 oct. 2019 à 23:56, Lars Maier <address@hidden> a écrit :
> 
> Hi,
> 
> I was debugging a GLR C parser and noticed that, while for the deterministic 
> LR parser the used rules come with line numbers, this is not true in 
> non-deterministic mode.
> 
> 
> $ diff glr2.c bison-3.4.2/data/skeletons/glr.c
> 1464c1464
> <                   "Reduced stack %lu by rule #%d (line %lu); action 
> deferred.  "
> ---
> >                   "Reduced stack %lu by rule #%d; action deferred.  "
> 1466c1466
> <                   (unsigned long) yyk, yyrule - 1, (unsigned long) 
> yyrline[yyrule], yynewLRState));
> ---
> >                   (unsigned long) yyk, yyrule - 1, yynewLRState));
> 
> 
> This is such a small change but might help others to debug their parsers.

You're right.  I installed this.  Thanks!

commit 2c20ae9b418f4687d643d3d266ac4b123b29d744
Author: Akim Demaille <address@hidden>
Date:   Fri Oct 11 07:06:39 2019 +0200

    glr: display line numbers in traces
    
    Suggested by Lars Maier.
    
    * data/skeletons/glr.c: Also display rule locations when rules are
    deferred, and rejected.

diff --git a/THANKS b/THANKS
index 569ba173..c29797e9 100644
--- a/THANKS
+++ b/THANKS
@@ -95,8 +95,9 @@ Kees Zeelenberg           address@hidden
 Keith Browne              address@hidden
 Ken Moffat                address@hidden
 Kiyoshi Kanazawa          address@hidden
-Laurent Mascherpa         address@hidden
+Lars Maier                address@hidden
 László Várady             address@hidden
+Laurent Mascherpa         address@hidden
 Lie Yan                   address@hidden
 Magnus Fromreide          address@hidden
 Marc Autret               address@hidden
diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index af7a78c3..7184a35a 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -1442,8 +1442,9 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, 
yyRuleNum yyrule,
       YYRESULTTAG yyflag = yydoAction (yystackp, yyk, yyrule, 
&yysval]b4_locuser_args([&yyloc])[);
       if (yyflag == yyerr && yystackp->yysplitPoint != YY_NULLPTR)
         {
-          YYDPRINTF ((stderr, "Parse on stack %ld rejected by rule #%d.\n",
-                     (long) yyk, yyrule - 1));
+          YYDPRINTF ((stderr,
+                      "Parse on stack %ld rejected by rule %d (line %d).\n",
+                      (long) yyk, yyrule - 1, yyrline[yyrule - 1]));
         }
       if (yyflag != yyok)
         return yyflag;
@@ -1469,9 +1470,9 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, 
yyRuleNum yyrule,
       yyupdateSplit (yystackp, yys);
       yynewLRState = yyLRgotoState (yys->yylrState, yylhsNonterm (yyrule));
       YYDPRINTF ((stderr,
-                  "Reduced stack %ld by rule #%d; action deferred.  "
+                  "Reduced stack %ld by rule %d (line %d); action deferred.  "
                   "Now in state %d.\n",
-                  (long) yyk, yyrule - 1, yynewLRState));
+                  (long) yyk, yyrule - 1, yyrline[yyrule - 1], yynewLRState));
       for (yyi = 0; yyi < yystackp->yytops.yysize; yyi += 1)
         if (yyi != yyk && yystackp->yytops.yystates[yyi] != YY_NULLPTR)
           {
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 1d4a5581..e6b8c01a 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -1711,10 +1711,10 @@ Reading a token: Now at end of input.
 Stack 0 Entering state 7
 Now at end of input.
 Splitting off stack 1 from 0.
-Reduced stack 1 by rule #2; action deferred.  Now in state 2.
+Reduced stack 1 by rule 2 (line 24); action deferred.  Now in state 2.
 Stack 1 Entering state 2
 Now at end of input.
-Reduced stack 0 by rule #1; action deferred.  Now in state 2.
+Reduced stack 0 by rule 1 (line 24); action deferred.  Now in state 2.
 Merging stack 0 into stack 1.
 Stack 1 Entering state 2
 Now at end of input.