Improve line tracker.

The new version is able to hold input history from several source lines,
which makes it easier to implement #line directives in lexers.

* include/mailutils/locus.h (mu_linetrack_stat): Remove start_line
(mu_linetrack_origin): New proto.
* libmailutils/locus/linetrack.c: Improve indexing.  Keep track of several
input files.
* libmailutils/tests/linetrack.at: Add new tests.
* libmailutils/tests/linetrack.c: Improve command set.

* mimeview/grammar.y (make_node): Initialize locus

5 files changed, 514 insertions, 113 deletions

diff --git a/include/mailutils/locus.h b/include/mailutils/locus.h
index f8efa1321..af18df078 100644
--- a/include/mailutils/locus.h
+++ b/include/mailutils/locus.h
@@ -43,10 +43,9 @@ typedef struct mu_linetrack *mu_linetrack_t;
 
 struct mu_linetrack_stat
 {
-  unsigned start_line;  /* Start line number (1-based) */
-  size_t n_lines;       /* Number of lines, including the recent (incomplete)
-			   one */
-  size_t n_chars;       /* Total number of characters */
+  size_t n_files; /* Number of source files */
+  size_t n_lines; /* Number of lines, including the recent (incomplete) one */
+  size_t n_chars; /* Total number of characters */
 };
   
 int mu_ident_ref (char const *name, char const **refname);
@@ -81,6 +80,7 @@ mu_locus_point_same_line (struct mu_locus_point const *a,
 
 int mu_linetrack_create (mu_linetrack_t *ret,
 			   char const *file_name, size_t max_lines);
+int mu_linetrack_origin (mu_linetrack_t trk, struct mu_locus_point const *pt);
 int mu_linetrack_rebase (mu_linetrack_t trk, struct mu_locus_point const *pt);
 void mu_linetrack_free (mu_linetrack_t trk);
 void mu_linetrack_destroy (mu_linetrack_t *trk);
diff --git a/libmailutils/locus/linetrack.c b/libmailutils/locus/linetrack.c
index 86a3dd823..a9f289835 100644
--- a/libmailutils/locus/linetrack.c
+++ b/libmailutils/locus/linetrack.c
@@ -21,46 +21,176 @@
 #include <mailutils/locus.h>
 #include <mailutils/error.h>
 
-/* The line-tracker structure keeps track of the last N lines read from a
-   text input file.  For each line read it keeps the number of characters
+/* The line-tracker structure keeps track of the last N lines read from one
+   or more input files.  For each line read it keeps the number of characters
    in that line including the newline.  This information is stored in a
-   syclic stack of N elements.  Top of stack always represents the current
-   line.  For the purpose of line tracker, current line is the line that is
-   being visited, such that its final newline character has not yet been
-   seen.  Once the newline is seen, the line is pushed on stack, and a new
-   current line is assumed.
+   cyclic stack of N elements (N >= 2).  Top of stack always represents the
+   current line.  For the purpose of line tracker, current line is the line
+   that is being visited, such that its final newline character has not yet
+   been seen.  Once the newline is seen, the line is pushed on stack, and a
+   new current line is assumed.
 
-   The value of N must not be less than 2.
+   Each input file is represented by a directory entry keeping its name,
+   number of the first line that is stored in the tracker and the index of
+   that line in the cols stack.  Entries form a doubly-linked list, with
+   head pointing to the most recent (current) source.  When a new line is
+   being added to the stack which is full, its eldest entry is discarded
+   and is assigned to that line and the directory of the eldest source is
+   updated accordingly.  If the entry represented the only line of the
+   source, the source is discarded.   
 */
-struct mu_linetrack
+
+struct source
 {
   char const *file_name; /* Name of the source file */
+  size_t idx;            /* Index of the first element on stack */
+  unsigned line;         /* Number of line corresponding to cols[idx] */
+  struct source *next, *prev;
+};
+
+struct mu_linetrack
+{
+  struct source *s_head, *s_tail;
+                         /* Directory of source files.  Most recent one is
+			    s_head */
+
   size_t max_lines;      /* Max. number of lines history kept by tracker (N) */
   size_t head;           /* Index of the eldest element on stack */
   size_t tos;            /* Index of the most recent element on stack
 			    (< max_lines) */
-  unsigned hline;        /* Number of line corresponding to cols[head] */
   unsigned *cols;        /* Cyclic stack or character counts.
-			    Number of characters in line (hline + n) is
+			    Number of characters in line (line + n) is
 			    cols[head + n] (0 <= n <= tos). */
 };
 
+static inline size_t
+trk_incr (struct mu_linetrack *trk, size_t a)
+{
+  return (a + 1) % trk->max_lines;
+}
+
+static inline size_t
+trk_decr (struct mu_linetrack *trk, size_t a)
+{
+  return (a + trk->max_lines - 1) % trk->max_lines;
+}
+	 
+static inline unsigned
+count_lines (mu_linetrack_t trk, size_t from)
+{
+  return (trk->tos + trk->max_lines - from) % trk->max_lines + 1;
+}
+
+#ifndef SIZE_MAX
+# define SIZE_MAX (~((size_t)0))
+#endif
+
+static int
+count_chars (struct mu_linetrack *trk, size_t i, size_t *ret)
+{
+  size_t nch = 0;
+
+  while (1)
+    {
+      unsigned n = trk->cols[i];
+      if (SIZE_MAX - nch < n)
+	return ERANGE;
+      nch += n;
+      if (i == trk->tos)
+	break;
+      i = trk_incr (trk, i);
+    }
+  *ret = nch;
+  return 0;
+}
+
+static size_t
+count_files (struct mu_linetrack *trk)
+{
+  struct source *sp;
+  size_t n = 0;
+  for (sp = trk->s_head; sp; sp = sp->next)
+    n++;
+  return n;
+}
+
+static void
+del_source (mu_linetrack_t trk, struct source *sp)
+{
+  if (sp->prev)
+    sp->prev->next = sp->next;
+  else
+    trk->s_head = sp->next;
+  if (sp->next)
+    sp->next->prev = sp->prev;
+  else
+    trk->s_tail = sp->prev;
+  mu_ident_deref (sp->file_name);
+  free (sp);
+}
+  
 static inline unsigned *
-cols_ptr (mu_linetrack_t trk, size_t n)
+push (mu_linetrack_t trk)
 {
-  return &trk->cols[(trk->head + n) % trk->max_lines];
+  trk->tos = trk_incr (trk, trk->tos);
+  if (trk->tos == trk->head)
+    {
+      trk->head = trk_incr (trk, trk->head);
+      trk->s_tail->idx = trk->head;
+      trk->s_tail->line++;
+    }
+  if (trk->s_tail->prev && trk->s_tail->idx == trk->s_tail->prev->idx)
+    del_source (trk, trk->s_tail);
+  trk->cols[trk->tos] = 0;
+  return &trk->cols[trk->tos];
 }
- 
+
 static inline unsigned *
-cols_tos_ptr (mu_linetrack_t trk)
+pop (mu_linetrack_t trk)
 {
-  return cols_ptr (trk, trk->tos);
+  if (trk->tos == trk->head)
+    return NULL;
+  if (trk->tos == trk->s_head->idx)
+    del_source (trk, trk->s_head);
+  
+  trk->tos = trk_decr (trk, trk->tos);
+  
+  return &trk->cols[trk->tos];
 }
 
-static inline unsigned
-cols_peek (mu_linetrack_t trk, size_t n)
+int
+mu_linetrack_origin (mu_linetrack_t trk, struct mu_locus_point const *pt)
 {
-  return *cols_ptr (trk, n);
+  int rc;
+  struct source *sp;
+  
+  if (!trk || !pt || !pt->mu_file || pt->mu_line == 0)
+    return EINVAL;
+  sp = malloc (sizeof *sp);
+  if (!sp)
+    return errno;
+  rc = mu_ident_ref (pt->mu_file, &sp->file_name);
+  if (rc)
+    {
+      free (sp);
+      return rc;
+    }
+
+  if (trk->cols[trk->tos])
+    push (trk);
+  
+  sp->idx = trk->tos;
+  sp->line = pt->mu_line;
+  trk->cols[sp->idx] = pt->mu_col;
+
+  sp->prev = NULL;
+  sp->next = trk->s_head;
+  if (trk->s_head)
+    trk->s_head->prev = sp;
+  else
+    trk->s_tail = sp;
+  trk->s_head = sp;
+  return 0;
 }
 
 int
@@ -69,10 +199,12 @@ mu_linetrack_create (mu_linetrack_t *ret,
 {
   int rc;
   struct mu_linetrack *trk;
+  struct mu_locus_point pt;
   
   trk = malloc (sizeof *trk);
   if (!trk)
     return errno;
+
   trk->cols = calloc (max_lines, sizeof (trk->cols[0]));
   if (!trk->cols)
     {
@@ -80,21 +212,25 @@ mu_linetrack_create (mu_linetrack_t *ret,
       free (trk);
       return rc;
     }
-  rc = mu_ident_ref (file_name, &trk->file_name);
-  if (rc)
-    {
-      free (trk->cols);
-      free (trk);
-      return rc;
-    }
-
+  trk->s_head = trk->s_tail = NULL;
+  
   if (max_lines < 2)
     max_lines = 2;
   trk->max_lines = max_lines;
   trk->head = 0;
   trk->tos = 0;
-  trk->hline = 1;
   trk->cols[0] = 0;
+
+  pt.mu_file = file_name;
+  pt.mu_line = 1;
+  pt.mu_col = 0;
+  rc = mu_linetrack_origin (trk, &pt);
+  if (rc)
+    {
+      free (trk->cols);
+      free (trk);
+      return rc;
+    }
   
   *ret = trk;
   return 0;
@@ -107,10 +243,10 @@ mu_linetrack_rebase (mu_linetrack_t trk, struct mu_locus_point const *pt)
   int rc = mu_ident_ref (pt->mu_file, &file_name);
   if (rc)
     return rc;
-  mu_ident_deref (trk->file_name);
-  trk->file_name = file_name;
-  trk->hline = pt->mu_line;
-  *cols_ptr (trk, 0) = pt->mu_col;
+  mu_ident_deref (trk->s_head->file_name);
+  trk->s_head->file_name = file_name;
+  trk->s_head->line = pt->mu_line;
+  trk->cols[trk->s_head->idx] = pt->mu_col;
   return 0;
 }
   
@@ -119,7 +255,8 @@ mu_linetrack_free (mu_linetrack_t trk)
 {
   if (trk)
     {
-      mu_ident_deref (trk->file_name);
+      while (trk->s_head)
+	del_source (trk, trk->s_head);
       free (trk->cols);
       free (trk);
     }
@@ -135,58 +272,20 @@ mu_linetrack_destroy (mu_linetrack_t *trk)
     }
 }   
 
-static inline unsigned *
-push (mu_linetrack_t trk)
-{
-  unsigned *ptr;
-  if (trk->tos == trk->max_lines - 1)
-    {
-      trk->head++;
-      trk->hline++;
-    }
-  else
-    trk->tos++;
-  *(ptr = cols_tos_ptr (trk)) = 0;
-  return ptr;
-}
-
-static inline unsigned *
-pop (mu_linetrack_t trk)
-{
-  if (trk->tos == 0)
-    return NULL;
-  trk->tos--;
-  return cols_tos_ptr (trk);
-}
-
-#ifndef SIZE_MAX
-# define SIZE_MAX (~((size_t)0))
-#endif
-
 int
 mu_linetrack_stat (struct mu_linetrack *trk, struct mu_linetrack_stat *st)
 {
-  size_t i, nch = 0;
-
-  for (i = 0; i <= trk->tos; i++)
-    {
-      unsigned n = cols_peek (trk, i);
-      if (SIZE_MAX - nch < n)
-	return ERANGE;
-      nch += n;
-    }
-  
-  st->start_line = trk->hline;
-  st->n_lines = trk->tos + 1;
-  st->n_chars = nch;
-
+  if (count_chars (trk, trk->head, &st->n_chars))
+    return ERANGE;
+  st->n_files = count_files (trk);
+  st->n_lines = count_lines (trk, trk->head);
   return 0;
 }
 
 int
 mu_linetrack_at_bol (struct mu_linetrack *trk)
 {
-  return *cols_tos_ptr (trk) == 0;
+  return trk->cols[trk->tos] == 0;
 }
 
 void
@@ -199,10 +298,11 @@ mu_linetrack_advance (struct mu_linetrack *trk,
   if (text == NULL || leng == 0)
     return;
 
-  mu_locus_point_set_file (&loc->beg, trk->file_name);
-  mu_locus_point_set_file (&loc->end, trk->file_name);
-  loc->beg.mu_line = trk->hline + trk->tos;
-  ptr = cols_tos_ptr (trk);
+  mu_locus_point_set_file (&loc->beg, trk->s_head->file_name);
+  mu_locus_point_set_file (&loc->end, trk->s_head->file_name);
+  loc->beg.mu_line =
+    trk->s_head->line + count_lines (trk, trk->s_head->idx) - 1;
+  ptr = &trk->cols[trk->tos];
   loc->beg.mu_col = *ptr + 1;
   while (leng--)
     {
@@ -211,16 +311,18 @@ mu_linetrack_advance (struct mu_linetrack *trk,
 	ptr = push (trk);
       text++;
     }
+
+  loc->end.mu_line =
+    trk->s_head->line + count_lines (trk, trk->s_head->idx) - 1;
   if (*ptr)
     {
-      loc->end.mu_line = trk->hline + trk->tos;
       loc->end.mu_col = *ptr;
     }
   else
     {
       /* Text ends with a newline.  Keep the previous line number. */
-      loc->end.mu_line = trk->hline + trk->tos - 1;
-      loc->end.mu_col = cols_peek (trk, trk->tos - 1) - 1;
+      loc->end.mu_line--;
+      loc->end.mu_col = trk->cols[trk_decr (trk, trk->tos)] - 1;
       if (loc->end.mu_col + 1 == loc->beg.mu_col)
 	{
 	  /* This happens if the previous line contained only newline. */
@@ -232,21 +334,28 @@ mu_linetrack_advance (struct mu_linetrack *trk,
 int
 mu_linetrack_locus (struct mu_linetrack *trk, struct mu_locus_point *lp)
 {
-  lp->mu_line = trk->hline + trk->tos;
-  return mu_locus_point_set_file (lp, trk->file_name);
+  int rc = mu_locus_point_set_file (lp, trk->s_head->file_name);
+  if (rc == 0)
+    {
+      lp->mu_line =
+	trk->s_head->line + count_lines (trk, trk->s_head->idx) - 1;
+      lp->mu_col = trk->cols[trk->tos];
+    }
+  return rc;
 }
 
 int
 mu_linetrack_retreat (struct mu_linetrack *trk, size_t n)
 {
-  struct mu_linetrack_stat st;
+  size_t nch;
 
-  mu_linetrack_stat (trk, &st);
-  if (n > st.n_chars)
+  if (count_chars (trk, trk->head, &nch))
+    return ERANGE;
+  if (n > nch)
     return ERANGE;
   else
     {
-      unsigned *ptr = cols_tos_ptr (trk);
+      unsigned *ptr = &trk->cols[trk->tos];
       while (n--)
 	{
 	  if (*ptr == 0)
diff --git a/libmailutils/tests/linetrack.at b/libmailutils/tests/linetrack.at
index 6f01b4d83..21d714413 100644
--- a/libmailutils/tests/linetrack.at
+++ b/libmailutils/tests/linetrack.at
@@ -54,11 +54,11 @@ liber:4.15-18: Naso
 TRACKTEST([retreat],[],[3],
 [
 agnosco
-\-4
+#retreat 4
 veteris
 vestigia\n
 flamme
-\-8
+#retreat 8
 Publius
 ],
 [liber:1.1-7: agnosco
@@ -73,7 +73,7 @@ TRACKTEST([retreat over several lines],[],[4],
 one\n
 two\n
 three
-\-11
+#retreat 11
 four
 ],
 [liber:1.1-3: one\n
@@ -85,7 +85,7 @@ liber:1.3-6: four
 TRACKTEST([retreat to the beginning],[],[4],
 [one\n
 two\n
-\-8
+#retreat 8
 three
 ],
 [liber:1.1-3: one\n
@@ -96,7 +96,7 @@ liber:1.1-5: three
 TRACKTEST([too big retreat],[],[2],
 [one\n
 two\n
-\-10
+#retreat 10
 three
 ],
 [liber:1.1-3: one\n
@@ -106,4 +106,174 @@ liber:3.1-5: three
 [linetrack: retreat count too big
 ])
 
+TRACKTEST([origin 1],[],[10],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#stat
+],
+[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+n_files=3
+n_lines=9
+n_chars=40
+])
+
+TRACKTEST([origin 2],[],[8],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#stat
+],
+[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+n_files=3
+n_lines=8
+n_chars=36
+])
+
+TRACKTEST([origin 3],[],[7],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#stat
+],
+[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+n_files=3
+n_lines=7
+n_chars=32
+])
+
+TRACKTEST([origin 4],[],[6],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#stat
+],
+[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+n_files=2
+n_lines=6
+n_chars=26
+])
+
+TRACKTEST([retreat over origin],[],[9],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#retreat 17
+nine
+#stat
+],[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+B:6.5-8: nine
+n_files=2
+n_lines=5
+n_chars=27
+])
+
+TRACKTEST([retreat over two origins],[],[9],
+[one\n
+two\n
+three\n
+#origin B 5 0
+four\n
+five\n
+#origin C 2 0
+six\n
+seven\n
+eight\n
+#retreat 32
+nine
+#stat
+],[liber:1.1-3: one\n
+liber:2.1-3: two\n
+liber:3.1-5: three\n
+B:5.1-4: four\n
+B:6.1-4: five\n
+C:2.1-3: six\n
+C:3.1-5: seven\n
+C:4.1-5: eight\n
+liber:3.1-4: nine
+n_files=1
+n_lines=3
+n_chars=12
+])
+
+TRACKTEST([rebase],[],[9],
+[one
+#rebase archivum 5 3
+two
+],
+[liber:1.1-3: one
+archivum:5.4-6: two
+])
+
+
 m4_popdef([TRACKTEST])
diff --git a/libmailutils/tests/linetrack.c b/libmailutils/tests/linetrack.c
index c99440e1f..1dc0c875d 100644
--- a/libmailutils/tests/linetrack.c
+++ b/libmailutils/tests/linetrack.c
@@ -2,6 +2,122 @@
 #include <mailutils/locus.h>
 
 int
+getnum (char const *arg, unsigned *ret)
+{
+  char *end;
+  unsigned long x = strtoul (arg, &end, 10);
+  if (*end)
+    {
+      mu_error ("bad number: %s", arg);
+      return -1;
+    }
+  *ret = x;
+  return 0;
+}
+
+static void
+com_retreat (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  unsigned x;
+  if (getnum (argv[1], &x) == 0)
+    {
+      int rc = mu_linetrack_retreat (trk, x);
+      if (rc == ERANGE)
+	mu_error ("retreat count too big");
+      else if (rc)
+	mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_retreat", argv[1], rc);
+    }
+}
+
+static void
+com_origin (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  int rc;
+  struct mu_locus_point pt;
+
+  pt.mu_file = argv[1];
+  if (getnum (argv[2], &pt.mu_line))
+    return;
+  if (getnum (argv[3], &pt.mu_col))
+    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;
+  struct mu_locus_point pt;
+
+  pt.mu_file = argv[1];
+  if (getnum (argv[2], &pt.mu_line))
+    return;
+  if (getnum (argv[3], &pt.mu_col))
+    return;
+  rc = mu_linetrack_rebase (trk, &pt);
+  if (rc)
+    mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_rebase", NULL, rc);
+}
+
+static void
+com_point (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  struct mu_locus_range lr = MU_LOCUS_RANGE_INITIALIZER;
+  int rc;
+  
+  rc = mu_linetrack_locus (trk, &lr.beg);
+  if (rc)
+    mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_locus", NULL, rc);
+  else
+    {
+      mu_stream_lprintf (mu_strout, &lr, "%s\n", argv[0]);
+      mu_locus_range_deinit (&lr);
+    }
+}
+
+static void
+com_bol_p (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  mu_printf ("%d\n", mu_linetrack_at_bol (trk));
+}
+
+static void
+com_stat (mu_linetrack_t trk, size_t argc, char **argv)
+{
+  int rc;
+  struct mu_linetrack_stat st;
+  
+  rc = mu_linetrack_stat (trk, &st);
+  if (rc)
+    mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_stat", NULL, rc);
+  else
+    {
+      mu_printf ("n_files=%zu\n", st.n_files);
+      mu_printf ("n_lines=%zu\n", st.n_lines);
+      mu_printf ("n_chars=%zu\n", st.n_chars);
+    }
+}
+
+struct command
+{
+  char *name;
+  size_t argc;
+  void (*fun) (mu_linetrack_t trk, size_t argc, char **argv);
+};
+
+static struct command comtab[] = {
+  { "retreat",   2, com_retreat },
+  { "origin",    4, com_origin },
+  { "point",     1, com_point },
+  { "rebase",    4, com_rebase },
+  { "bol",       1, com_bol_p },
+  { "stat",      1, com_stat },
+  { NULL }
+};
+
+int
 main (int argc, char **argv)
 {
   unsigned long max_lines;
@@ -10,6 +126,9 @@ main (int argc, char **argv)
   int rc;
   char *buf = NULL;
   size_t size, n;
+  struct mu_wordsplit ws;
+  int wsf = MU_WRDSF_NOVAR | MU_WRDSF_NOCMD
+            | MU_WRDSF_SHOWERR | MU_WRDSF_ENOMEMABRT;
   
   mu_set_program_name (argv[0]);
   mu_stdstream_setup (MU_STDSTREAM_RESET_NONE);
@@ -29,35 +148,37 @@ main (int argc, char **argv)
   MU_ASSERT (mu_linetrack_create (&trk, argv[1], max_lines));
   while ((rc = mu_stream_getline (mu_strin, &buf, &size, &n)) == 0 && n > 0)
     {
-      struct mu_locus_range lr = MU_LOCUS_RANGE_INITIALIZER;
       char *tok;
       
       n = mu_rtrim_class (buf, MU_CTYPE_SPACE);
       if (n == 0)
 	continue;
-      if (buf[0] == '\\' && buf[1] == '-')
+      if (buf[0] == '#')
 	{
-	  long x = strtol (buf+2, &end, 10);
-	  if (*end || x == 0)
-	    {
-	      mu_error ("bad number");
-	      continue;
-	    }
-	  rc = mu_linetrack_retreat (trk, x);
-	  if (rc == ERANGE)
-	    mu_error ("retreat count too big");
-	  else if (rc)
-	    mu_diag_funcall (MU_DIAG_ERROR, "mu_linetrack_retreat", buf+2,
-			     rc);
+	  struct command *com;
+
+	  mu_wordsplit (buf+1, &ws, wsf);
+	  wsf |= MU_WRDSF_REUSE;
+
+	  for (com = comtab; com->name; com++)
+	    if (strcmp (com->name, ws.ws_wordv[0]) == 0
+		&& com->argc == ws.ws_wordc)
+	      break;
+	  if (com->name)
+	    com->fun (trk, ws.ws_wordc, ws.ws_wordv);
+	  else
+	    mu_error ("unrecognized command");
 	}
       else
 	{
+	  struct mu_locus_range lr = MU_LOCUS_RANGE_INITIALIZER;
+	  
 	  mu_c_str_unescape (buf, "\\\n", "\\n", &tok);
 	  mu_linetrack_advance (trk, &lr, tok, strlen (tok));
 	  free (tok);
 	  mu_stream_lprintf (mu_strout, &lr, "%s\n", buf);
+	  mu_locus_range_deinit (&lr);
 	}
-      mu_locus_range_deinit (&lr);
     }
   mu_linetrack_destroy (&trk);
   return 0;
diff --git a/mimeview/grammar.y b/mimeview/grammar.y
index cb36f3941..0a860104a 100644
--- a/mimeview/grammar.y
+++ b/mimeview/grammar.y
@@ -315,6 +315,7 @@ make_node (enum node_type type, struct mu_locus_range const *loc)
 {
   struct node *p = mimetypes_malloc (sizeof *p);
   p->type = type;
+  mu_locus_range_init (&p->loc);
   mu_locus_range_copy (&p->loc, loc);
   return p;
 }