bug#21147: readline history is stifled early so (readline-set! history-length nn) has no effect

bug#21147: readline history is stifled early so (readline-set! history-length nn) has no effect

[Daniel Llorens]

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The default history-length is 200. When one imports (ice-9 readline), history is stifled to this value, so it doesn't matter if you set history-length to a larger value later on. I'm surprised that this has gone unnoticed up to now, since 200 is really small. I may be missing something...

The patch changes scm_readline_options() so that history is only stiffled when the options are actually set. This is rather clumsy since it means that if one doesn't set the options, history will never be stifled.

An alternative would be to add an optional readline-options argument to activate-readline. That way one would be able to increase history-length before the first time history is stifled, and otherwise things would work as they do now.

Regards
	
	Daniel



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From 06397e42cd700690bdac0650e9e3cee9b6dfbcb4 Mon Sep 17 00:00:00 2001
From: Daniel Llorens <daniel.llorens@bluewin.ch>
Date: Tue, 28 Jul 2015 09:42:25 +0200
Subject: [PATCH] Avoid stifling readline history when looking up options

With this patch, history is never stifled unless (readline-set!) is used.

* src/guile-readline/readline.c (scm_readline_options)
---
 guile-readline/readline.c | 56 ++++++++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/guile-readline/readline.c b/guile-readline/readline.c
index aac6e18..a3e8903 100644
--- a/guile-readline/readline.c
+++ b/guile-readline/readline.c
@@ -2,17 +2,17 @@
 
 /* Copyright (C) 1997,1999,2000,2001, 2002, 2003, 2006, 2007, 2008,
  *   2009, 2010, 2013 Free Software Foundation, Inc.
- * 
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 3, or (at your option)
  * any later version.
- * 
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU General Public License
  * along with this software; see the file COPYING.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
@@ -52,7 +52,7 @@ scm_t_option scm_readline_opts[] = {
 
 extern void stifle_history (int max);
 
-SCM_DEFINE (scm_readline_options, "readline-options-interface", 0, 1, 0, 
+SCM_DEFINE (scm_readline_options, "readline-options-interface", 0, 1, 0,
             (SCM setting),
 "")
 #define FUNC_NAME s_scm_readline_options
@@ -60,7 +60,9 @@ SCM_DEFINE (scm_readline_options, "readline-options-interface", 0, 1, 0,
   SCM ans = scm_options (setting,
 			 scm_readline_opts,
 			 FUNC_NAME);
-  stifle_history (SCM_HISTORY_LENGTH);
+  if (!SCM_UNBNDP (setting)) {
+    stifle_history (SCM_HISTORY_LENGTH);
+  }
   return ans;
 }
 #undef FUNC_NAME
@@ -107,13 +109,13 @@ void
 rl_free_line_state ()
 {
   register HIST_ENTRY *entry;
-   
+
   free_undo_list ();
 
   entry = current_history ();
   if (entry)
-    entry->data = (char *)NULL; 
-  
+    entry->data = (char *)NULL;
+
   _rl_kill_kbd_macro ();
   rl_clear_message ();
   _rl_init_argument ();
@@ -145,15 +147,15 @@ static void unwind_readline (void *unused);
 static void reentry_barrier (void);
 
 
-SCM_DEFINE (scm_readline, "%readline", 0, 4, 0, 
+SCM_DEFINE (scm_readline, "%readline", 0, 4, 0,
             (SCM text, SCM inp, SCM outp, SCM read_hook),
 "")
 #define FUNC_NAME s_scm_readline
 {
   SCM ans;
-  
+
   reentry_barrier ();
-  
+
   before_read = SCM_BOOL_F;
 
   if (!SCM_UNBNDP (text))
@@ -164,7 +166,7 @@ SCM_DEFINE (scm_readline, "%readline", 0, 4, 0,
 	  scm_wrong_type_arg (s_scm_readline, SCM_ARG1, text);
 	}
     }
-  
+
   if (!((SCM_UNBNDP (inp) && SCM_OPINFPORTP (scm_current_input_port ()))
 	|| SCM_OPINFPORTP (inp)))
     {
@@ -173,7 +175,7 @@ SCM_DEFINE (scm_readline, "%readline", 0, 4, 0,
 		      "Input port is not open or not a file port",
 		      SCM_EOL);
     }
-  
+
   if (!((SCM_UNBNDP (outp) && SCM_OPOUTFPORTP (scm_current_output_port ()))
 	|| SCM_OPOUTFPORTP (outp)))
     {
@@ -197,7 +199,7 @@ SCM_DEFINE (scm_readline, "%readline", 0, 4, 0,
 
   scm_dynwind_begin (0);
   scm_dynwind_unwind_handler (unwind_readline, NULL, 0);
-  
+
   ans = internal_readline (text);
 
   scm_dynwind_end ();
@@ -249,7 +251,7 @@ internal_readline (SCM text)
   s = readline (prompt);
   if (s)
     ret = scm_from_port_string (s, output_port);
-  else 
+  else
     ret = SCM_EOF_VAL;
 
   if (!SCM_UNBNDP (text))
@@ -287,10 +289,10 @@ scm_readline_init_ports (SCM inp, SCM outp)
 {
   if (SCM_UNBNDP (inp))
     inp = scm_current_input_port ();
-  
+
   if (SCM_UNBNDP (outp))
     outp = scm_current_output_port ();
-  
+
   if (!SCM_OPINFPORTP (inp)) {
     scm_misc_error (0,
                     "Input port is not open or not a file port",
@@ -311,7 +313,7 @@ scm_readline_init_ports (SCM inp, SCM outp)
 
 
 
-SCM_DEFINE (scm_add_history, "add-history", 1, 0, 0, 
+SCM_DEFINE (scm_add_history, "add-history", 1, 0, 0,
             (SCM text),
 "")
 #define FUNC_NAME s_scm_add_history
@@ -327,7 +329,7 @@ SCM_DEFINE (scm_add_history, "add-history", 1, 0, 0,
 #undef FUNC_NAME
 
 
-SCM_DEFINE (scm_read_history, "read-history", 1, 0, 0, 
+SCM_DEFINE (scm_read_history, "read-history", 1, 0, 0,
             (SCM file),
 "")
 #define FUNC_NAME s_scm_read_history
@@ -343,7 +345,7 @@ SCM_DEFINE (scm_read_history, "read-history", 1, 0, 0,
 #undef FUNC_NAME
 
 
-SCM_DEFINE (scm_write_history, "write-history", 1, 0, 0, 
+SCM_DEFINE (scm_write_history, "write-history", 1, 0, 0,
             (SCM file),
 "")
 #define FUNC_NAME s_scm_write_history
@@ -358,7 +360,7 @@ SCM_DEFINE (scm_write_history, "write-history", 1, 0, 0,
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_clear_history, "clear-history", 0, 0, 0, 
+SCM_DEFINE (scm_clear_history, "clear-history", 0, 0, 0,
             (),
 	    "Clear the history buffer of the readline machinery.")
 #define FUNC_NAME s_scm_clear_history
@@ -369,7 +371,7 @@ SCM_DEFINE (scm_clear_history, "clear-history", 0, 0, 0,
 #undef FUNC_NAME
 
 
-SCM_DEFINE (scm_filename_completion_function, "filename-completion-function", 2, 0, 0, 
+SCM_DEFINE (scm_filename_completion_function, "filename-completion-function", 2, 0, 0,
             (SCM text, SCM continuep),
 "")
 #define FUNC_NAME s_scm_filename_completion_function
@@ -408,10 +410,10 @@ completion_function (char *text, int continuep)
       SCM t = scm_from_locale_string (text);
       SCM c = scm_from_bool (continuep);
       res = scm_apply (compfunc, scm_list_2 (t, c), SCM_EOL);
-  
+
       if (scm_is_false (res))
 	return NULL;
-  
+
       return scm_to_locale_string (res);
     }
 }
@@ -525,7 +527,7 @@ scm_init_readline ()
   rl_getc_function = current_input_getc;
 #if defined (_RL_FUNCTION_TYPEDEF)
   rl_completion_entry_function = (rl_compentry_func_t*) completion_function;
-#else  
+#else
   rl_completion_entry_function = (Function*) completion_function;
 #endif
   rl_basic_word_break_characters = " \t\n\"'`;()";
@@ -535,12 +537,12 @@ scm_init_readline ()
 #if defined (HAVE_DECL_RL_CATCH_SIGNALS) && HAVE_DECL_RL_CATCH_SIGNALS
   rl_catch_signals = 0;
 #endif
-  
+
   /* But let readline handle SIGWINCH. */
 #if defined (HAVE_DECL_RL_CATCH_SIGWINCH) && HAVE_DECL_RL_CATCH_SIGWINCH
   rl_catch_sigwinch = 1;
 #endif
-  
+
   reentry_barrier_mutex = scm_make_mutex ();
   scm_init_opts (scm_readline_options,
 		 scm_readline_opts);
-- 
2.4.6

bug#21147: readline history is stifled early so (readline-set! history-length nn) has no effect

[Andy Wingo]

On Tue 28 Jul 2015 10:06, Daniel Llorens <daniel.llorens@bluewin.ch> writes:

> The default history-length is 200. When one imports (ice-9 readline),
> history is stifled to this value, so it doesn't matter if you set
> history-length to a larger value later on. I'm surprised that this has
> gone unnoticed up to now, since 200 is really small. I may be missing
> something...
>
> The patch changes scm_readline_options() so that history is only
> stiffled when the options are actually set. This is rather clumsy
> since it means that if one doesn't set the options, history will never
> be stifled.
>
> An alternative would be to add an optional readline-options argument
> to activate-readline. That way one would be able to increase
> history-length before the first time history is stifled, and otherwise
> things would work as they do now.

Thanks for the patch!  Well why not.  It's not perfect but it's an
improvement.  Thanks for giving this a poke; applied to master.

Andy

bug#21147: readline history is stifled early so (readline-set! history-length nn) has no effect

[Andy Wingo]

thanks