bash

x.sh

#/usr/bin/env bash

function bar {
	[[ -n $READLINE_LINE ]] || return 0;

	eval "
		function f {
			$READLINE_LINE
		};
	" 2> /dev/null || { bind '"\C-x3": edit-and-execute-command' && i=1; };
};

function foo {
	((i)) && bind '"\C-x3": accept-line' && i=0;
};

bind '"\C-x3": accept-line';
bind -x '"\C-x2": foo;bar';
bind '"\C-x1": "\C-x2\C-x3"';

y.sh

#!/usr/bin/env bash

function lich {
	READLINE_LINE=$(
		function p { printf '%s\n' "$READLINE_LINE"; };

		n='\!';
		nn=/tmp/bash.$$.hn.${n@P};
		\p > "$nn";

		vim -f \
		 "+set ft=sh" "+call cursor(1,$READLINE_POINT+1)" "$nn" </dev/tty >/dev/tty;

		if
			cmp -s <(\p) "$nn";
		then
			\p;
			return 1;
		else
			cat "$nn";
		fi;
	);
};

function bar {
	until
		[[ -n $READLINE_LINE ]] || return 0;
		eval "
			function f {
				$READLINE_LINE
			};
		" 2> /dev/null
	do
		lich || { i=1; bind '"\C-x3": abort'; break; }
	done;
};

function foo {
	((i)) && bind '"\C-x3": accept-line' && i=0;
};

i=1;
bind -x '"\C-x2": foo;bar';
bind '"\C-x1": "\C-x2\C-x3"';