Re: discoverability, better defaults and which-key in Emacs

[Dmitry Gutov <dmitry@gutov.dev>]

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On 06/02/2024 04:49, Justin Burkett wrote:
>> What is missing is the note in the echo area that tells the user to
>> press C-h after a timeout (like 200ms or so) if they want help in the
>> middle of typing a key sequence.
> True, but I think a message like that could be useful regardless of
> whether which-key is active (i.e., for `describe-prefix-bindings`).

Right. :)

How about this?

Since echo-keystrokes is 1 second by default, which defines a 
significant timeout already, I think this can work without a yet another 
timer.

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diff --git a/src/keyboard.c b/src/keyboard.c
index 1f7253a7da1..6d3db5ab615 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -589,6 +589,15 @@ echo_dash (void)
   AUTO_STRING (dash, "-");
   kset_echo_string (current_kboard,
 		    concat2 (KVAR (current_kboard, echo_string), dash));
+
+  if (echo_keystrokes_help)
+    {
+      AUTO_STRING (help, " (\\`C-h' for help)");
+      kset_echo_string (current_kboard,
+			concat2 (KVAR (current_kboard, echo_string),
+				 calln (Qsubstitute_command_keys, help)));
+    }
+
   echo_now ();
 }
 
@@ -13228,6 +13237,10 @@ syms_of_keyboard (void)
 If the value is zero, don't echo at all.  */);
   Vecho_keystrokes = make_fixnum (1);
 
+  DEFVAR_BOOL ("echo-keystrokes-help", echo_keystrokes_help,
+	       doc: /* Non-nil means append small help text to the unfinished commands' echo. */);
+  echo_keystrokes_help = true;
+
   DEFVAR_LISP ("polling-period", Vpolling_period,
 	      doc: /* Interval between polling for input during Lisp execution.
 The reason for polling is to make C-g work to stop a running program.