reports: display %empty in the generated pointed-rules

* src/print.c (print_core): Use %empty for empty rules.
* src/print_graph.c (print_core): Ditto.
* tests/conflicts.at, tests/output.at, tests/reduce.at: Adjust
expectations.

src/print.c

@@ -106,8 +106,11 @@ print_core (FILE *out, state *s)
       for (sp = rules[r].rhs; sp < sp1; sp++)
         fprintf (out, " %s", symbols[*sp]->tag);
       fputs (" .", out);
-      for (/* Nothing */; *sp >= 0; ++sp)
-        fprintf (out, " %s", symbols[*sp]->tag);
+      if (0 <= *rules[r].rhs)
+        for (/* Nothing */; 0 <= *sp; ++sp)
+          fprintf (out, " %s", symbols[*sp]->tag);
+      else
+        fprintf (out, " %%empty");
 
       /* Display the lookahead tokens?  */
       if (report_flag & report_lookahead_tokens

src/print_graph.c

@@ -84,8 +84,11 @@ print_core (struct obstack *oout, state *s)
 
       obstack_1grow (oout, '.');
 
-      for (/* Nothing */; *sp >= 0; ++sp)
-        obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
+      if (0 <= *r->rhs)
+        for (/* Nothing */; *sp >= 0; ++sp)
+          obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
+      else
+        obstack_printf (oout, " %%empty");
 
       /* Experimental feature: display the lookahead tokens. */
       if (report_flag & report_lookahead_tokens

tests/conflicts.at

@@ -1447,7 +1447,7 @@ State 0
     0 $accept: . start $end
     1 start: . resolved_conflict 'a' reported_conflicts 'a'
     2 resolved_conflict: . 'a' unreachable1
-    3                  | .  ['a']
+    3                  | . %empty  ['a']
 
     $default  reduce using rule 3 (resolved_conflict)
 
@@ -1483,7 +1483,7 @@ State 4
     1 start: resolved_conflict 'a' . reported_conflicts 'a'
     8 reported_conflicts: . 'a'
     9                   | . 'a'
-   10                   | .  ['a']
+   10                   | . %empty  ['a']
 
     'a'  shift, and go to state 5
 
@@ -1576,11 +1576,11 @@ AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
     6      | . empty_c1 'c'
     7      | . empty_c2 'c'
     8      | . empty_c3 'c'
-    9 empty_a: .  ['a']
-   10 empty_b: .  []
-   11 empty_c1: .  []
-   12 empty_c2: .  []
-   13 empty_c3: .  ['c']
+    9 empty_a: . %empty  ['a']
+   10 empty_b: . %empty  []
+   11 empty_c1: . %empty  []
+   12 empty_c2: . %empty  []
+   13 empty_c3: . %empty  ['c']
 
     'b'  shift, and go to state 1
 
@@ -1652,11 +1652,11 @@ AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
     6      | . empty_c1 'c'
     7      | . empty_c2 'c'
     8      | . empty_c3 'c'
-    9 empty_a: .  []
-   10 empty_b: .  []
-   11 empty_c1: .  []
-   12 empty_c2: .  ['c']
-   13 empty_c3: .  ['c']
+    9 empty_a: . %empty  []
+   10 empty_b: . %empty  []
+   11 empty_c1: . %empty  []
+   12 empty_c2: . %empty  ['c']
+   13 empty_c3: . %empty  ['c']
 
     'a'  error (nonassociative)
     'b'  error (nonassociative)

tests/output.at

@@ -290,7 +290,7 @@ a: ;
 b: 'b';
 ]],
 [[
-  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a '?' b\l  2 a: .\l"]
+  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a '?' b\l  2 a: . %empty\l"]
   0 -> 1 [style=dashed label="exp"]
   0 -> 2 [style=dashed label="a"]
   0 -> "0R2" [style=solid]
@@ -332,7 +332,7 @@ empty_b: %prec 'b';
 empty_c: %prec 'c';
 ]],
 [[
-  0 [label="State 0\n\l  0 $accept: . start $end\l  1 start: . 'a'\l  2      | . empty_a 'a'\l  3      | . 'b'\l  4      | . empty_b 'b'\l  5      | . 'c'\l  6      | . empty_c 'c'\l  7 empty_a: .  ['a']\l  8 empty_b: .  ['b']\l  9 empty_c: .  ['c']\l"]
+  0 [label="State 0\n\l  0 $accept: . start $end\l  1 start: . 'a'\l  2      | . empty_a 'a'\l  3      | . 'b'\l  4      | . empty_b 'b'\l  5      | . 'c'\l  6      | . empty_c 'c'\l  7 empty_a: . %empty  ['a']\l  8 empty_b: . %empty  ['b']\l  9 empty_c: . %empty  ['c']\l"]
   0 -> 1 [style=solid label="'a'"]
   0 -> 2 [style=solid label="'b'"]
   0 -> 3 [style=solid label="'c'"]
@@ -399,7 +399,7 @@ empty_b: %prec 'b';
 empty_c: %prec 'c';
 ]],
 [[
-  0 [label="State 0\n\l  0 $accept: . start $end\l  1 start: . 'a'\l  2      | . empty_a 'a'\l  3      | . 'b'\l  4      | . empty_b 'b'\l  5      | . 'c'\l  6      | . empty_c 'c'\l  7 empty_a: .  ['a']\l  8 empty_b: .  []\l  9 empty_c: .  []\l"]
+  0 [label="State 0\n\l  0 $accept: . start $end\l  1 start: . 'a'\l  2      | . empty_a 'a'\l  3      | . 'b'\l  4      | . empty_b 'b'\l  5      | . 'c'\l  6      | . empty_c 'c'\l  7 empty_a: . %empty  ['a']\l  8 empty_b: . %empty  []\l  9 empty_c: . %empty  []\l"]
   0 -> 1 [style=solid label="'b'"]
   0 -> 2 [style=solid label="'c'"]
   0 -> 3 [style=dashed label="start"]
@@ -447,7 +447,7 @@ a: ;
 b: ;
 ]],
 [[
-  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a\l  2    | . b\l  3 a: .  [$end]\l  4 b: .  [$end]\l"]
+  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a\l  2    | . b\l  3 a: . %empty  [$end]\l  4 b: . %empty  [$end]\l"]
   0 -> 1 [style=dashed label="exp"]
   0 -> 2 [style=dashed label="a"]
   0 -> 3 [style=dashed label="b"]
@@ -480,7 +480,7 @@ b: ;
 c: ;
 ]],
 [[
-  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a ';'\l  2    | . a ';'\l  3    | . a '.'\l  4    | . b '?'\l  5    | . b '!'\l  6    | . c '?'\l  7    | . c ';'\l  8 a: .  [';', '.']\l  9 b: .  ['?', '!']\l 10 c: .  [';', '?']\l"]
+  0 [label="State 0\n\l  0 $accept: . exp $end\l  1 exp: . a ';'\l  2    | . a ';'\l  3    | . a '.'\l  4    | . b '?'\l  5    | . b '!'\l  6    | . c '?'\l  7    | . c ';'\l  8 a: . %empty  [';', '.']\l  9 b: . %empty  ['?', '!']\l 10 c: . %empty  [';', '?']\l"]
   0 -> 1 [style=dashed label="exp"]
   0 -> 2 [style=dashed label="a"]
   0 -> 3 [style=dashed label="b"]
@@ -595,7 +595,7 @@ imm: '0';
  "11R7d" [label="R7", fillcolor=5, shape=diamond, style=filled]
   11 -> "11R7" [style=solid]
  "11R7" [label="R7", fillcolor=3, shape=diamond, style=filled]
-  12 [label="State 12\n\l  4 ifexp: \"if\" exp \"then\" exp . elseexp\l  5 elseexp: . \"else\" exp\l  6        | .  [$end, \"then\", \"else\", '+']\l  7 opexp: exp . '+' exp\l"]
+  12 [label="State 12\n\l  4 ifexp: \"if\" exp \"then\" exp . elseexp\l  5 elseexp: . \"else\" exp\l  6        | . %empty  [$end, \"then\", \"else\", '+']\l  7 opexp: exp . '+' exp\l"]
   12 -> 13 [style=solid label="\"else\""]
   12 -> 9 [style=solid label="'+'"]
   12 -> 14 [style=dashed label="elseexp"]

tests/reduce.at

@@ -1057,7 +1057,7 @@ State 12
 
     4 A: 'a' 'a' . B
     5 B: . 'a'
-    6  | .  ]AT_COND_CASE([[LALR]], [[['a', 'b']]], [[['a']]])[
+    6  | . %empty  ]AT_COND_CASE([[LALR]], [[['a', 'b']]], [[['a']]])[
 
     ]AT_COND_CASE([[canonical LR]], [['a']],
                   [[$default]])[  reduce using rule 6 (B)
@@ -1087,7 +1087,7 @@ State 15
 
     4 A: 'a' 'a' . B
     5 B: . 'a'
-    6  | .  [$end]
+    6  | . %empty  [$end]
     7 c: 'a' 'a' . 'b'
 
     'a'  shift, and go to state ]AT_COND_CASE([[canonical LR]], [[20]],
@@ -1150,7 +1150,7 @@ State 22]])[
 
     4 A: 'a' 'a' . B
     5 B: . 'a'
-    6  | .  ['b']
+    6  | . %empty  ['b']
 
     'a'  shift, and go to state ]AT_COND_CASE([[canonical LR]], [[23]],
                                               [[16]])[
@@ -1575,8 +1575,8 @@ State 3
     1 start: a . b
     2      | a . b 'a'
     3      | a . c 'b'
-    5 b: .  [$end, 'a']
-    6 c: .  ['b']]AT_COND_CASE([[most]], [[
+    5 b: . %empty  [$end, 'a']
+    6 c: . %empty  ['b']]AT_COND_CASE([[most]], [[
 
     'b'       reduce using rule 6 (c)
     $default  reduce using rule 5 (b)]], [[