diff --git a/contrib/10.readline/src/readline.c b/contrib/10.readline/src/readline.c
index fb043dd7..e5a33258 100644
--- a/contrib/10.readline/src/readline.c
+++ b/contrib/10.readline/src/readline.c
@@ -28,6 +28,14 @@ pic_rl_readline(pic_state *pic)
     return pic_eof_object();
 }
 
+static pic_value
+pic_rl_history_length(pic_state *pic)
+{
+  pic_get_args(pic, "");
+
+  return pic_int_value(history_get_history_state()->length);
+}
+
 static pic_value
 pic_rl_add_history(pic_state *pic)
 {
@@ -70,20 +78,20 @@ pic_rl_history_is_stifled(pic_state *pic)
   return pic_bool_value(history_is_stifled());
 }
 
-static pic_value
-pic_rl_history_length(pic_state *pic)
-{
-  pic_get_args(pic, "");
-
-  return pic_int_value(history_length);
-}
-
 static pic_value
 pic_rl_where_history(pic_state *pic)
 {
   pic_get_args(pic, "");
 
-  return pic_int_value(where_history());  
+  return pic_int_value(where_history());
+}
+
+static pic_value
+pic_rl_current_history(pic_state *pic)
+{
+  pic_get_args(pic, "");
+
+  return pic_obj_value(pic_str_new_cstr(pic, current_history()->line));
 }
 
 static pic_value
@@ -95,10 +103,23 @@ pic_rl_history_get(pic_state *pic)
   pic_get_args(pic, "i", &i);
   
   e = history_get(i);
-  if(!e)
-    pic_errorf(pic, "failed to get entry");
 
-  return pic_obj_value(pic_str_new_cstr(pic, e->line));
+  return e ? pic_obj_value(pic_str_new_cstr(pic, e->line))
+    : pic_false_value();
+}
+
+static pic_value
+pic_rl_remove_history(pic_state *pic)
+{
+  int i;
+  HIST_ENTRY *e;
+
+  pic_get_args(pic, "i", &i);
+  
+  e = remove_history(i);
+
+  return e ? pic_obj_value(pic_str_new_cstr(pic, e->line))
+    : pic_false_value();
 }
 
 static pic_value
@@ -112,15 +133,64 @@ pic_rl_clear_history(pic_state *pic)
 }
 
 static pic_value
-pic_rl_remove_history(pic_state *pic)
+pic_rl_history_set_pos(pic_state *pic)
 {
   int i;
 
   pic_get_args(pic, "i", &i);
 
-  remove_history(i);
-  
-  return pic_undef_value();
+
+  return pic_int_value(history_set_pos(i));
+}
+
+static pic_value
+pic_rl_previous_history(pic_state *pic)
+{
+  HIST_ENTRY *e;
+
+  pic_get_args(pic, "");
+
+  e = previous_history();
+
+  return e ? pic_obj_value(pic_str_new_cstr(pic, e->line))
+    : pic_false_value();
+}
+
+static pic_value
+pic_rl_next_history(pic_state *pic)
+{
+  HIST_ENTRY *e;
+
+  pic_get_args(pic, "");
+
+  e = next_history();
+
+  return e ? pic_obj_value(pic_str_new_cstr(pic, e->line))
+    : pic_false_value();
+}
+
+static pic_value
+pic_rl_history_search(pic_state *pic)
+{
+  char *key;
+  int direction, pos, argc;
+
+  argc = pic_get_args(pic, "zi|i", &key, &direction, &pos);
+  if(argc == 2)
+    return pic_int_value(history_search(key, direction));
+  else
+    return pic_int_value(history_search_pos(key, direction, pos));
+}
+
+static pic_value
+pic_rl_history_search_prefix(pic_state *pic)
+{
+  char *key;
+  int direction;
+
+  pic_get_args(pic, "zi", &key, &direction);
+
+  return pic_int_value(history_search_prefix(key, direction));
 }
 
 static pic_value
@@ -169,15 +239,22 @@ pic_init_readline(pic_state *pic){
     pic_defun(pic, "readline", pic_rl_readline);
   }
   pic_deflibrary (pic, "(picrin readline history)") {
+    /* pic_defun(pic, "history-offset", pic_rl_history_offset); */
+    pic_defun(pic, "history-length", pic_rl_history_length);
     pic_defun(pic, "add-history", pic_rl_add_history);
     pic_defun(pic, "stifle-history", pic_rl_stifle_history);
     pic_defun(pic, "unstifle-history", pic_rl_unstifle_history);
     pic_defun(pic, "history-stifled?", pic_rl_history_is_stifled);
-    pic_defun(pic, "history-length", pic_rl_history_length);
     pic_defun(pic, "where-history", pic_rl_where_history);
+    pic_defun(pic, "current-history", pic_rl_current_history);
     pic_defun(pic, "history-get", pic_rl_history_get);
     pic_defun(pic, "clear-history", pic_rl_clear_history);
     pic_defun(pic, "remove-history", pic_rl_remove_history);
+    pic_defun(pic, "history-set-pos", pic_rl_history_set_pos);
+    pic_defun(pic, "previous-history", pic_rl_previous_history);
+    pic_defun(pic, "next-history", pic_rl_next_history);
+    pic_defun(pic, "history-search", pic_rl_history_search);
+    pic_defun(pic, "history-search-prefix", pic_rl_history_search_prefix);
     pic_defun(pic, "read-history", pic_rl_read_history);
     pic_defun(pic, "write-history", pic_rl_write_history);
     pic_defun(pic, "truncate-file", pic_rl_truncate_file);