why does 'event-to-character return nil for backspace?

I needed the attached patch to make anthy.el ((X)Emacs interface for the Japanese input method "Anthy") work correctly when XEmacs is started in a terminal ("xemacs -nw"). Without that patch, XEmacs would just beep when trying to delete the last character in the preedit string with backspace. The reason it beeped was that (char-to-int (event-to-character event)) fails in case of backspace because (event-to-character event) is nil in case of backspace. One can easily check that (event-to-character (character-to-event 'backspace)) returns nil. This is different from most other characters. Please have a look at these examples: example: (character-to-event 'a) #<keypress-event a> (event-to-character (character-to-event 'a)) ?a (character-to-event 'return) #<keypress-event return> (event-to-character (character-to-event 'return)) ?\r (character-to-event 'tab) #<keypress-event tab> (event-to-character (character-to-event 'tab)) ?\t I.e. these behave as expected. But 'backspace, 'left, 'right and some others behave differently (character-to-event 'backspace) #<keypress-event backspace> (event-to-character (character-to-event 'backspace)) nil (character-to-event 'left) #<keypress-event left> (event-to-character (character-to-event 'left)) nil (character-to-event 'right) #<keypress-event right> (event-to-character (character-to-event 'right)) nil Just like non-existing characters (character-to-event 'foo) #<keypress-event foo> (event-to-character (character-to-event 'foo)) nil But the backspace event exists and I checked that #<keypress-event backspace> is indeed in last-command-event when I hit the backspace key. So why does (event-to-character (character-to-event 'backspace)) return nil? Apparently somebody already tried to workaround this problem in anthy.el with the 3 lines removed by my patch. But this didn't work in a terminal because (event-matches-key-specifier-p (character-to-event 'backspace) 'backspace) returns nil when XEmacs in running in a terminal. It returns t when XEmacs is running under X11. Why this difference? (equal (character-to-event 'backspace) (character-to-event 'backspace)) returns t both in a terminal and under X11, therefore my patch helped. But I still don't understand why. -- Mike FABIAN <mfabian(a)suse.de&gt; http://www.suse.de/~mfabian 睡眠不足はいい仕事の敵だ。