In Bison 1.875's yacc.c, YYLLOC_DEFAULT was called regardless

whether the reducion was empty or not.  This leaves room to
improve the use of YYLLOC_DEFAULT in such a case.
lalr1.cc is still experimental, so changing this is acceptable.
And finally, there are probably not many users who changed the
handling of locations in GLR, so changing is admissible too.
* data/glr.c, data/lalr1.cc, data/yacc.c (YYLLOC_DEFAULT): On an
empty reduction, set @$ to an empty location ending the previously
stacked symbol.
Adjust uses to make sure the code is triggered on empty
reductions.
* tests/actions.at (_AT_CHECK_PRINTER_AND_DESTRUCTOR): Adjust the
expected output: empty reductions have empty locations.

diff --git a/ChangeLog b/ChangeLog
index b2e72695a244757ec1ef76400912f9e1c81ca869..845b21cc8d62da5611d66af6ed8d8a86dba07e1e 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2004-10-05  Akim Demaille  <akim@epita.fr>
+
+       In Bison 1.875's yacc.c, YYLLOC_DEFAULT was called regardless
+       whether the reducion was empty or not.  This leaves room to
+       improve the use of YYLLOC_DEFAULT in such a case.
+       lalr1.cc is still experimental, so changing this is acceptable.
+       And finally, there are probably not many users who changed the
+       handling of locations in GLR, so changing is admissible too.
+
+       * data/glr.c, data/lalr1.cc, data/yacc.c (YYLLOC_DEFAULT): On an
+       empty reduction, set @$ to an empty location ending the previously
+       stacked symbol.
+       Adjust uses to make sure the code is triggered on empty
+       reductions.
+       * tests/actions.at (_AT_CHECK_PRINTER_AND_DESTRUCTOR): Adjust the
+       expected output: empty reductions have empty locations.
+
 2004-09-29  Akim Demaille  <akim@epita.fr>
 
        * data/lalr1.cc: Move towards a more standard C++ coding style

diff --git a/data/glr.c b/data/glr.c
index 0e569841b32e2a2dcbc93007717d97514ed6b5a7..7f4c92165d18e6844b5d10384b162305ef9664a9 100644 (file)
--- a/data/glr.c
+++ b/data/glr.c
@@ -420,17 +420,31 @@ static const ]b4_int_type_for([b4_stos])[ yystos[] =
 /* Error token number */
 #define YYTERROR 1
 
-/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].  */
+/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
+   If N is 0, then set CURRENT to the empty location which ends
+   the previous symbol: RHS[0] (always defined).  */
 
 ]b4_location_if([[
 #define YYRHSLOC(yyRhs,YYK) ((yyRhs)[YYK].yystate.yyloc)
 
 #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)
+# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN)                         \
+do {                                                                   \
+  if (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;     \
+    }                                                                  \
+  else                                                                 \
+    {                                                                  \
+      (yyCurrent).first_line   = YYRHSLOC(yyRhs, 0).last_line;         \
+      (yyCurrent).first_column = YYRHSLOC(yyRhs, 0).last_column;       \
+      (yyCurrent).last_line    = YYRHSLOC(yyRhs, 0).last_line;         \
+      (yyCurrent).last_column  = YYRHSLOC(yyRhs, 0).last_column;       \
+    }                                                                  \
+} while(0)
 
 /* YY_LOCATION_PRINT -- Print the location on the stream.
    This macro was not mandated originally: define only if we know
@@ -718,15 +732,10 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
 
   yylow = 1;
   if (yyrhslen == 0)
-    {
-      *yyvalp = yyval_default;
-      *yylocp = yyvsp[0].yystate.yyloc;
-    }
+    *yyvalp = yyval_default;
   else
-    {
-      *yyvalp = yyvsp[YYFILL (1-yyrhslen)].yystate.yysemantics.yysval;
-      YYLLOC_DEFAULT (*yylocp, yyvsp - yyrhslen, yyrhslen);
-    }
+    *yyvalp = yyvsp[YYFILL (1-yyrhslen)].yystate.yysemantics.yysval;
+  YYLLOC_DEFAULT (*yylocp, yyvsp - yyrhslen, yyrhslen);
 
 ]
   switch (yyn)

diff --git a/data/lalr1.cc b/data/lalr1.cc
index 8405171098fbd9852998cc832f8e45907b5e62c3..e77e784262a612c4e75bbd9a2c605022372a628b 100644 (file)
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -181,13 +181,22 @@ b4_syncline([@oline@], [@ofile@])],
 
 ]/* Line __line__ of lalr1.cc.  */
 b4_syncline([@oline@], [@ofile@])[
-/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].  */
+/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
+   If N is 0, then set CURRENT to the empty location which ends
+   the previous symbol: RHS[0] (always defined).  */
 
 #ifndef YYLLOC_DEFAULT
-# define YYLLOC_DEFAULT(Current, Rhs, N)       \
-do {                                           \
-   ((Current).begin = (Rhs)[1].begin);         \
-   ((Current).end   = (Rhs)[N].end);           \
+# define YYLLOC_DEFAULT(Current, Rhs, N)               \
+do {                                                   \
+  if (N)                                               \
+    {                                                  \
+      (Current).begin = (Rhs)[1].begin;                        \
+      (Current).end   = (Rhs)[N].end;                  \
+    }                                                  \
+  else                                                 \
+    {                                                  \
+      (Current).begin = (Current).end = (Rhs)[0].end;  \
+    }                                                  \
 } while (0)
 #endif
 
@@ -583,21 +592,14 @@ yyreduce:
      This behavior is undocumented and Bison
      users should not rely upon it.  */
   if (len_)
-    {
-      yyval = semantic_stack_[len_ - 1];
-      yyloc = location_stack_[len_ - 1];
-    }
+    yyval = semantic_stack_[len_ - 1];
   else
-    {
-      yyval = semantic_stack_[0];
-      yyloc = location_stack_[0];
-    }
+    yyval = semantic_stack_[0];
 
-  if (len_)
-    {
-      Slice<LocationType, LocationStack> slice (location_stack_, len_);
-      YYLLOC_DEFAULT (yyloc, slice, len_);
-    }
+  {
+    Slice<LocationType, LocationStack> slice (location_stack_, len_);
+    YYLLOC_DEFAULT (yyloc, slice, len_);
+  }
   YY_REDUCE_PRINT (n_);
   switch (n_)
     {

diff --git a/data/yacc.c b/data/yacc.c
index 575d2624e6386b2436caeb851cfa6665ae1d47a0..2e9c9fd0b0d04859b5fa1f8fad95e97b3b19fb82 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -506,14 +506,26 @@ while (0)
 #define YYERRCODE      256
 
 
-/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].  */
+/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
+   If N is 0, then set CURRENT to the empty location which ends
+   the previous symbol: RHS[0] (always defined).  */
 
 #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)                                    \
+do {                                                                        \
+  if (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;                        \
+    }                                                                       \
+  else                                                                      \
+    {                                                                       \
+      (Current).first_line   = (Current).last_line   = (Rhs)[0].last_line;   \
+      (Current).first_column = (Current).last_column = (Rhs)[0].last_column; \
+    }                                                                       \
+} while(0)
 #endif
 
 
@@ -1021,10 +1033,7 @@ yyreduce:
 
 ]b4_location_if(
 [[  /* Default location. */
-  if (yylen)
-    YYLLOC_DEFAULT (yyloc, yylsp - yylen, yylen);
-  else
-    yyloc = yylsp[0];]])[
+  YYLLOC_DEFAULT (yyloc, yylsp - yylen, yylen);]])[
   YY_REDUCE_PRINT (yyn);
   switch (yyn)
     ]{

diff --git a/tests/actions.at b/tests/actions.at
index 2ffaffb204c829e7a11d1bac00e33dae21de7afe..05d0e52b28ef051dc95ce24e448b5a2d3979680b 100644 (file)
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -372,8 +372,8 @@ thing (1@10-19): 'x' (1@10-19)
 sending: ')' (2@20-29)
 line (0@0-29): '(' (0@0-9) thing (1@10-19) ')' (2@20-29)
 sending: EOF (3@30-39)
-input (0@0-29): /* Nothing */
-input (2@0-29): line (0@0-29) input (0@0-29)
+input (0@29-29): /* Nothing */
+input (2@0-29): line (0@0-29) input (0@29-29)
 Successful parse.
 ]])
 
@@ -390,8 +390,8 @@ Freeing token 'y' (1@10-19)
 sending: ')' (2@20-29)
 line (-1@0-29): '(' (0@0-9) error (@10-19) ')' (2@20-29)
 sending: EOF (3@30-39)
-input (0@0-29): /* Nothing */
-input (2@0-29): line (-1@0-29) input (0@0-29)
+input (0@29-29): /* Nothing */
+input (2@0-29): line (-1@0-29) input (0@29-29)
 Successful parse.
 ]])
 
@@ -438,8 +438,8 @@ thing (11@110-119): 'x' (11@110-119)
 sending: ')' (12@120-129)
 line (10@100-129): '(' (10@100-109) thing (11@110-119) ')' (12@120-129)
 sending: 'y' (13@130-139)
-input (0@100-129): /* Nothing */
-input (2@100-129): line (10@100-129) input (0@100-129)
+input (0@129-129): /* Nothing */
+input (2@100-129): line (10@100-129) input (0@129-129)
 input (2@70-129): line (7@70-99) input (2@100-129)
 input (2@0-129): line (-1@0-69) input (2@70-129)
 130-139: syntax error, unexpected 'y', expecting $end