[key bindings]
<F5> = swap
<F6> = dup
<Shift-F5> = roll<
<Shift-F6> = roll>
<F7> = over
<Shift-F7> = tuck
<F8> = parse
<F12> = words
<F1> = reset_log show_log
<Escape> = clear reset_log show_log
<Control-Delete> = pop
<Control-i> = i