lalr: print the 'reads' relation

[Akim Demaille]

commit a415a78d718118b0bd494e4b6c7d97e683753df9
Author: Akim Demaille <address@hidden>
Date:   Tue Feb 26 06:55:07 2019 +0100

    lalr: print the 'reads' relation
    
    * src/relation.h, src/relation.c (relation_print): Accept and use a
    title.
    Don't print empty rows.
    Indent the output.
    Adjust dependencies.
    * src/lalr.c (initialize_goto_follows): Print 'reads' in traces.

diff --git a/src/ielr.c b/src/ielr.c
index e0f53c21..11aa4d58 100644
--- a/src/ielr.c
+++ b/src/ielr.c
@@ -196,10 +196,7 @@ ielr_compute_internal_follow_edges (bitset 
ritem_sees_lookahead_set,
   relation_transpose (edgesp, ngotos);
 
   if (trace_flag & trace_ielr)
-    {
-      fprintf (stderr, "internal_follow_edges:\n");
-      relation_print (*edgesp, ngotos, NULL, stderr);
-    }
+    relation_print ("internal_follow_edges", *edgesp, ngotos, NULL, stderr);
 }
 
 /**
@@ -304,8 +301,7 @@ ielr_compute_always_follows (goto_number ***edgesp,
 
   if (trace_flag & trace_ielr)
     {
-      fprintf (stderr, "always follow edges:\n");
-      relation_print (*edgesp, ngotos, NULL, stderr);
+      relation_print ("always follow edges", *edgesp, ngotos, NULL, stderr);
       fprintf (stderr, "always_follows:\n");
       debug_bitsetv (*always_followsp);
     }
diff --git a/src/lalr.c b/src/lalr.c
index fd239dc3..3837eed4 100644
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -68,7 +68,7 @@ static goto_number **includes;
 static goto_list **lookback;
 
 static void
-goto_print (goto_number i, FILE* out)
+goto_print (goto_number i, FILE *out)
 {
   const state_number src = from_state[i];
   const state_number dst = to_state[i];
@@ -193,6 +193,8 @@ initialize_goto_follows (void)
         }
     }
 
+  if (trace_flag & trace_automaton)
+    relation_print ("reads", reads, ngotos, goto_print, stderr);
   relation_digraph (reads, ngotos, goto_follows);
 
   for (goto_number i = 0; i < ngotos; ++i)
@@ -282,15 +284,12 @@ build_relations (void)
 
   relation_transpose (&includes, ngotos);
   if (trace_flag & trace_automaton)
-    {
-      fprintf (stderr, "includes:\n");
-      relation_print (includes, ngotos, goto_print, stderr);
-    }
+    relation_print ("includes", includes, ngotos, goto_print, stderr);
 }
 
 /* Print FOLLOWS for debugging.  */
 static void
-follows_print (FILE* out)
+follows_print (FILE *out)
 {
   for (goto_number i = 0; i < ngotos; ++i)
     {
diff --git a/src/relation.c b/src/relation.c
index 0e9db9d8..24f7a473 100644
--- a/src/relation.c
+++ b/src/relation.c
@@ -27,17 +27,21 @@
 #include "relation.h"
 
 void
-relation_print (relation r, relation_node size,
+relation_print (const char *title,
+                relation r, relation_node size,
                 relation_node_print print, FILE *out)
 {
+  if (title)
+    fprintf (out, "%s:\n", title);
   for (size_t i = 0; i < size; ++i)
-    {
-      if (print)
-        print (i, out);
-      else
-        fprintf (out, "%3lu", (unsigned long) i);
-      fputc (':', out);
-      if (r[i])
+    if (r[i])
+      {
+        fputs ("    ", out);
+        if (print)
+          print (i, out);
+        else
+          fprintf (out, "%3lu", (unsigned long) i);
+        fputc (':', out);
         for (relation_node j = 0; r[i][j] != END_NODE; ++j)
           {
             fputc (' ', out);
@@ -46,8 +50,8 @@ relation_print (relation r, relation_node size,
             else
               fprintf (out, "%3lu", (unsigned long) r[i][j]);
           }
-      fputc ('\n', out);
-    }
+        fputc ('\n', out);
+      }
   fputc ('\n', out);
 }
 
@@ -130,10 +134,7 @@ relation_transpose (relation *R_arg, relation_node size)
   relation r = *R_arg;
 
   if (trace_flag & trace_sets)
-    {
-      fputs ("relation_transpose: input\n", stderr);
-      relation_print (r, size, NULL, stderr);
-    }
+    relation_print ("relation_transpose", r, size, NULL, stderr);
 
   /* Count. */
   /* NEDGES[I] -- total size of NEW_R[I]. */
@@ -175,10 +176,7 @@ relation_transpose (relation *R_arg, relation_node size)
   free (r);
 
   if (trace_flag & trace_sets)
-    {
-      fputs ("relation_transpose: output\n", stderr);
-      relation_print (new_R, size, NULL, stderr);
-    }
+    relation_print ("relation_transpose: output", new_R, size, NULL, stderr);
 
   *R_arg = new_R;
 }
diff --git a/src/relation.h b/src/relation.h
index e90c052f..81d766c1 100644
--- a/src/relation.h
+++ b/src/relation.h
@@ -36,7 +36,8 @@ typedef relation_nodes *relation;
 typedef void (relation_node_print) (relation_node node, FILE* out);
 
 /* Report a relation R that has SIZE vertices.  */
-void relation_print (relation r, size_t size,
+void relation_print (const char *title,
+                     relation r, size_t size,
                      relation_node_print print, FILE *out);
 
 /* Compute the transitive closure of the FUNCTION on the relation R