linetrack: handle #line directives without file name.

* include/mailutils/diag.h (mu_vdiag_at_locus_range): New proto.
* libmailutils/locus/linetrack.c (mu_linetrack_origin): accept
locus point with mu_file==NULL.  Reuse current file name in this
case.  This is to simplify handling of #line directives without
file name.
* libmailutils/tests/linetrack.c: Implement #line directive.
* libmailutils/tests/linetrack.at: Add new test.

@@ -52,6 +52,8 @@ void mu_diag_cont_printf (const char *fmt, ...) MU_PRINTFLIKE(1,2);
   
 void mu_diag_voutput (int, const char *, va_list);
 void mu_diag_output (int, const char *, ...) MU_PRINTFLIKE(2,3);
+void mu_vdiag_at_locus_range (int level, struct mu_locus_range const *loc,
+			      const char *fmt, va_list ap);
 void mu_diag_at_locus_point (int level, struct mu_locus_point const *loc,
 			     const char *fmt, ...);
 void mu_diag_at_locus_range (int level, struct mu_locus_range const *loc,

@@ -163,13 +163,20 @@ mu_linetrack_origin (mu_linetrack_t trk, struct mu_locus_point const *pt)
 {
   int rc;
   struct source *sp;
+  char const *file_name;
   
-  if (!trk || !pt || !pt->mu_file || pt->mu_line == 0)
+  if (!trk || !pt || pt->mu_line == 0)
+    return EINVAL;
+  if (pt->mu_file)
+    file_name = pt->mu_file;
+  else if (trk->s_head)
+    file_name = trk->s_head->file_name;
+  else
     return EINVAL;
   sp = malloc (sizeof *sp);
   if (!sp)
     return errno;
-  rc = mu_ident_ref (pt->mu_file, &sp->file_name);
+  rc = mu_ident_ref (file_name, &sp->file_name);
   if (rc)
     {
       free (sp);

@@ -18,7 +18,7 @@ AT_BANNER([Line tracker])
 
 m4_pushdef([TRACKTEST],[
 AT_SETUP([$1])
-AT_KEYWORDS([tracker $2])
+AT_KEYWORDS([tracker linetrack $2])
 AT_CHECK([linetrack liber $3 <<EOT
 $4[]EOT
 ],
@@ -275,5 +275,20 @@ two
 archivum:5.4-6: two
 ])
 
+TRACKTEST([#line directive],[],[9],
+[agnosco
+veteris\n
+vestigia
+#line 20
+flamme\n
+#retreat 8
+Naso
+],
+[liber:1.1-7: agnosco
+liber:1.8-14: veteris\n
+liber:2.1-8: vestigia
+liber:20.1-6: flamme\n
+liber:2.8-11: Naso
+])
 
 m4_popdef([TRACKTEST])

@@ -46,6 +46,19 @@ com_origin (mu_linetrack_t trk, size_t argc, char **argv)
 }
 
 static void
+com_line (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  int rc;
+  struct mu_locus_point pt = MU_LOCUS_POINT_INITIALIZER;
+
+  if (getnum (argv[1], &pt.mu_line))
+    return;
+  rc = mu_linetrack_origin (trk, &pt);
+  if (rc)
+    mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_origin", NULL, rc);
+}
+
+static void
 com_rebase (mu_linetrack_t trk, size_t argc, char **argv)
 {
   int rc;
@@ -110,6 +123,7 @@ struct command
 static struct command comtab[] = {
   { "retreat",   2, com_retreat },
   { "origin",    4, com_origin },
+  { "line",      2, com_line },
   { "point",     1, com_point },
   { "rebase",    4, com_rebase },
   { "bol",       1, com_bol_p },