traces: always print the reduced grammar and fix it

[Akim Demaille]

commit 21a7fa8063171de5afae1caae506b0e0b10a5824
Author: Akim Demaille <address@hidden>
Date:   Wed Jan 23 07:26:23 2019 +0100

    traces: always print the reduced grammar and fix it
    
    * src/gram.c (grammar_dump): Print the effective number first instead
    of last.  And fix it (remove the incorrect "+1").
    Use t/f for Booleans.
    * src/reduce.c: When asked, always print the reduced grammar, even if
    there was nothing useless.
    * tests/sets.at (Reduced Grammar): Check that.

diff --git a/src/gram.c b/src/gram.c
index 82f9d275..54aa7342 100644
--- a/src/gram.c
+++ b/src/gram.c
@@ -237,27 +237,28 @@ grammar_dump (FILE *out, const char *title)
 
   fprintf (out, "Rules\n-----\n\n");
   {
+    /* Reduced number, then original number in the sources.  */
     fprintf (out,
-             "Num (Prec, Assoc, Useful, Ritem Range) Lhs"
-             " -> Rhs (Ritem range) [Num]\n");
-    for (rule_number i = 0; i < nrules + nuseless_productions; i++)
+             "Num (Num, Prec, Assoc, Useful, UselessChain, Ritem Range)"
+             " Lhs -> Rhs (Ritem range)\n");
+    for (rule_number i = 0; i < nrules + nuseless_productions; ++i)
       {
         rule const *rule_i = &rules[i];
         unsigned const rhs_itemno = rule_i->rhs - ritem;
         unsigned length = rule_rhs_length (rule_i);
-        fprintf (out, "%3d (%2d, %2d, %2d, %2u-%2u)   %2d ->",
+        fprintf (out, "%3d (%3d, %2d, %2d, %2s, %2u-%2u)   %2d ->",
+                 item_number_as_rule_number (rule_i->rhs[length]),
                  i,
                  rule_i->prec ? rule_i->prec->prec : 0,
                  rule_i->prec ? rule_i->prec->assoc : 0,
-                 rule_i->useful,
+                 rule_i->useful ? "t" : "f",
                  rhs_itemno,
                  rhs_itemno + length - 1,
                  rule_i->lhs->number);
         /* Dumped the RHS. */
         for (item_number *rhsp = rule_i->rhs; 0 <= *rhsp; ++rhsp)
           fprintf (out, " %3d", *rhsp);
-        fprintf (out, "  [%d]\n",
-                 item_number_as_rule_number (rule_i->rhs[length+1]));
+        fputc ('\n', out);
       }
   }
   fprintf (out, "\n\n");
diff --git a/src/reduce.c b/src/reduce.c
index 56a90754..574e9b07 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -378,9 +378,8 @@ reduce_grammar (void)
   inaccessable_symbols ();
 
   /* Did we reduce something? */
-  if (!nuseless_nonterminals && !nuseless_productions)
-    return;
-
+  if (nuseless_nonterminals || nuseless_productions)
+    {
       reduce_print ();
 
       if (!bitset_test (N, accept->content->number - ntokens))
@@ -395,6 +394,7 @@ reduce_grammar (void)
         nonterminals_reduce ();
       if (nuseless_productions)
         reduce_grammar_tables ();
+    }
 
   if (trace_flag & trace_grammar)
     {
diff --git a/tests/sets.at b/tests/sets.at
index 7cd254a9..01339c22 100644
--- a/tests/sets.at
+++ b/tests/sets.at
@@ -300,3 +300,63 @@ AT_CHECK([sed -n '
         0, [expout])
 
 AT_CLEANUP
+
+
+
+## ----------------- ##
+## Reduced Grammar.  ##
+## ----------------- ##
+
+# Check information about the grammar, once reduced.
+
+AT_SETUP([Reduced Grammar])
+
+AT_DATA([input.y],
+[[%%
+expr: expr "+" term | term
+term: term "*" fact | fact
+fact: "num"
+]])
+
+AT_BISON_CHECK([[--trace=grammar -o input.c input.y]], [], [],
+[[Reduced Grammar
+
+ntokens = 6, nvars = 4, nsyms = 10, nrules = 6, nritems = 17
+
+Variables
+---------
+
+Value  Sprec  Sassoc  Tag
+    6      0       0  $accept
+    7      0       0  expr
+    8      0       0  term
+    9      0       0  fact
+
+
+Rules
+-----
+
+Num (Num, Prec, Assoc, Useful, UselessChain, Ritem Range) Lhs -> Rhs (Ritem 
range)
+  0 (  0,  0,  0,  t,  0- 1)    6 ->   7   0
+  1 (  1,  0,  0,  t,  3- 5)    7 ->   7   3   8
+  2 (  2,  0,  0,  t,  7- 7)    7 ->   8
+  3 (  3,  0,  0,  t,  9-11)    8 ->   8   4   9
+  4 (  4,  0,  0,  t, 13-13)    8 ->   9
+  5 (  5,  0,  0,  t, 15-15)    9 ->   5
+
+
+Rules interpreted
+-----------------
+
+0      $accept: expr $end
+1      expr: expr "+" term
+2      expr: term
+3      term: term "*" fact
+4      term: fact
+5      fact: "num"
+
+
+reduced input.y defines 6 terminals, 4 nonterminals, and 6 productions.
+]])
+
+AT_CLEANUP