Re: yank-last-arg with numeric argument doesn't work as intended in vi mode

[Leo Alekseyev]

On Mon, Jun 8, 2020 at 3:30 PM Chet Ramey <chet.ramey@case.edu> wrote:
>
> ................
> On 6/8/20 12:46 AM, Leo Alekseyev wrote:
>
> > set keymap vi-insert
> > "\e.":yank-last-arg
>
> Even with those first two changes, which will be in the next bash devel
> branch push, you'll have to be very careful with this. This key binding
> introduces ambiguity: either you want to run the function bound to ESC,
> which puts you into vi command mode, or you want to run yank-last-arg or
> any other function with an ESC meta prefix. Readline has to read an
> additional character to disambiguate, and it needs to read it with a half
> second or so to be part of the key sequence (this is the standard readline
> way to tell the difference between ambiguous prefixes). If you take longer
> than a half second, you might find yourself running the `.' (redo) command.

Thank you for fixing this bug. Regarding the ambiguity, it is my
assumption that the intended use of bindings like "\e." in vi mode is
to enable alt/meta chords, i.e. the user would never actually want to
press "ESC ." to invoke the yank-last-arg or whatever else function.
With this in mind, as it stands, "M-." would invoke yank-last-arg
immediately (with the above binding), while "ESC ." would invoke the
redo command (with the 500 ms timeout after ESC). Empirically, the 500
ms ESC timeout does not result in usability issues. So it seems that
such bindings while technically ambiguous are not problematic given
the intended use case; correct me if I'm wrong on this.