Make `view-lossage' output of chars read from `read-char' more logical

* lisp/help.el (view-lossage): Use the new data format to output
data from `read-char' and the like in a more understandable
fashion (bug#21867).

* src/keyboard.c (command_loop_1): Record (in recent_keys) the end
of commands.
(Frecent_keys): Don't include `end-of-command' in non-command outputs.
(syms_of_keyboard): Define `end-of-command'.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 30686a25898..158daba260c 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -307,6 +307,7 @@ static Lisp_Object command_loop (void);
 
 static void echo_now (void);
 static ptrdiff_t echo_length (void);
+static void record_char (Lisp_Object c);
 
 /* Incremented whenever a timer is run.  */
 unsigned timers_run;
@@ -1421,6 +1422,8 @@ command_loop_1 (void)
               Fcons (Qnil, cmd));
         if (++recent_keys_index >= NUM_RECENT_KEYS)
           recent_keys_index = 0;
+        /* Mark this as a complete command in recent_keys. */
+        record_char (Qend_of_command);
       }
       Vthis_command = cmd;
       Vreal_this_command = cmd;
@@ -1471,6 +1474,9 @@ command_loop_1 (void)
 
       safe_run_hooks (Qpost_command_hook);
 
+      /* Mark this as a complete command in recent_keys. */
+      record_char (Qend_of_command);
+
       /* If displaying a message, resize the echo area window to fit
          that message's size exactly.  Do this only if the echo area
          window is the minibuffer window of the selected frame.  See
@@ -2089,7 +2095,6 @@ show_help_echo (Lisp_Object help, Lisp_Object window, Lisp_Object object,
 
 static Lisp_Object kbd_buffer_get_event (KBOARD **kbp, bool *used_mouse_menu,
                                          struct timespec *end_time);
-static void record_char (Lisp_Object c);
 
 static Lisp_Object help_form_saved_window_configs;
 static void
@@ -9996,7 +10001,9 @@ represented as pseudo-events of the form (nil . COMMAND).  */)
       do
         {
           Lisp_Object e = AREF (recent_keys, i);
-          if (cmds || !CONSP (e) || !NILP (XCAR (e)))
+          if (cmds
+              || ((!CONSP (e) || !NILP (XCAR (e)))
+                  && !EQ (e, Qend_of_command)))
             es = Fcons (e, es);
           if (++i >= NUM_RECENT_KEYS)
             i = 0;
@@ -11066,6 +11073,8 @@ syms_of_keyboard (void)
 
   DEFSYM (Qundefined, "undefined");
 
+  DEFSYM (Qend_of_command, "end-of-command");
+
   /* Hooks to run before and after each command.  */
   DEFSYM (Qpre_command_hook, "pre-command-hook");
   DEFSYM (Qpost_command_hook, "post-command-hook");