interface to readline

[Thomas Walter]

Hello,
I updated my local changes to the interface between readline and
octave from the '2.0.xx' to the '2.1.xx' version.
This little patch disables double entries in the history list.  This
means if you re-enter the previous line it NOT added to the history
list.
The octave internal organization has changed. Currently I included the
readline headers again at the point where I needed them.  The missing
interface function of octave is a wrapper to the readline function
'using_history()'.

For reference I add my patch at the end.

Bye
Thomas

==== patch start ==============
Index: octave-2_1_28CVS.2/liboctave/ChangeLog
--- octave-2_1_28CVS.2/liboctave/ChangeLog Thu, 24 Feb 2000 13:35:53 +0100 
twalter (octave_devel/p/32_ChangeLog 1.2.1.1.1.1.1.1.1.1.1.1 640)
+++ octave-2_1_28CVS.2(w)/liboctave/ChangeLog Thu, 24 Feb 2000 14:42:28 +0100 
twalter (octave_devel/p/32_ChangeLog 1.2.1.1.1.1.1.1.1.1.1.1 640)
@@ -1,3 +1,8 @@
+2000-02-24  Thomas Walter  <address@hidden>
+
+       * cmd-hist.cc (compare_history_entries): New function.
+       (do_add): Apply my changes to ignore duplicate history entries.
+
 2000-02-18  John W. Eaton  <address@hidden>
 
        * oct-rl-hist.c (octave_history_list): Do something when not
Index: octave-2_1_28CVS.2/liboctave/cmd-hist.cc
--- octave-2_1_28CVS.2/liboctave/cmd-hist.cc Wed, 09 Feb 2000 10:43:09 +0100 
twalter (octave_devel/r/6_cmd-hist.c 1.1.4.1 640)
+++ octave-2_1_28CVS.2(w)/liboctave/cmd-hist.cc Thu, 24 Feb 2000 14:07:11 +0100 
twalter (octave_devel/r/6_cmd-hist.c 1.1.4.1 640)
@@ -115,18 +115,72 @@ private:
   int mark;
 };
 
+#define READLINE_SHALL_IGNORE_DUPLICATES 1
+#if defined(READLINE_SHALL_IGNORE_DUPLICATES)
+#include <readline/history.h>
+
+static bool
+compare_history_entries (const char* previous, const char* current)
+{
+  // Compare two strings from a command history
+  // Return 'false' if they are different
+  // Return 'true' if they are equal
+
+  if (previous[0] != current[0])
+    {
+      return (false);
+    }
+
+  if (((long *)previous)[0] != ((long *)current)[0])
+    {
+      return (false);
+    }
+
+  if (strlen (previous) != strlen (current))
+    {
+      return (false);
+    }
+
+  if (strcmp (previous, current) == 0)
+    {
+      return (true);
+    }
+
+  // In the case something fails be conservative and say they are different.
+  // And make the compiler happy to see always a return value.
+  return (false);
+}
+
+#endif  // READLINE_SHALL_IGNORE_DUPLICATES
+
 void
 gnu_history::do_add (const std::string& s)
 {
   if (! do_ignoring_entries ())
     {
+#if defined(READLINE_SHALL_IGNORE_DUPLICATES)
+      HIST_ENTRY *p_h_entry;
+
+#endif  // READLINE_SHALL_IGNORE_DUPLICATES
       if (s.empty ()
          || (s.length () == 1 && (s[0] == '\r' || s[0] == '\n')))
        return;
 
+#if defined(READLINE_SHALL_IGNORE_DUPLICATES)
+      using_history ();                // Must be called always at this point 
or 'p_h_entry' has the wrong value.
+      p_h_entry = previous_history ();
+      // cout << p_h_entry->line << endl; // Simple debugging
+      if ((p_h_entry == 0) || (compare_history_entries (p_h_entry->line, 
s.c_str ()) == false))
+       {
+         ::octave_add_history (s.c_str ());
+
+         lines_this_session++;
+       }
+#else  // !READLINE_SHALL_IGNORE_DUPLICATES
       ::octave_add_history (s.c_str ());
 
       lines_this_session++;
+#endif // !READLINE_SHALL_IGNORE_DUPLICATES
     }
 }
 
==== patch end ==============


-- 
Warum hat eine Leiterbahn keine 90 Grad Winkel sondern 2 mal 45 Grad?
Weil die Elektronen sonst immer gegen die Wand laufen 8-)))

----------------------------------------------
Dipl. Phys. Thomas Walter
Inst. f. Physiklische Chemie II
Egerlandstr. 3                          Tel.: ++9131-85 27326 / 27330
91058 Erlangen, Germany                 email: address@hidden