Add prompt mode and process OSC 51 as UI Command

* eat.el (eat-enable-native-shell-prompt-editing)
(eat-prompt-input-ring-size)
(eat-prompt-move-point-for-matching-input): New user option.
* eat.el (eat--t-term): Remove slots 'cwd', 'prompt-start-fn',
'prompt-end-fn', 'cont-prompt-start-fn', 'cont-prompt-end-fn',
'cmd-start-fn' and 'cmd-finish-fn'.  Add new slot 'ui-cmd-fn'.
* eat.el (eat--t-set-cwd): Support only the format used by OSC
7.
* eat.el (eat--t-prompt-start,  eat--t-prompt-end)
(eat--t-cont-prompt-start,  eat--t-cont-prompt-end)
(eat--t-set-cmd, eat--t-cmd-start, eat--t-cmd-finish): Remove
function.
* eat.el (eat--t-ui-cmd): New function.
* eat.el (eat--t-handle-output): Remove all specialized OSC 51
handlers and call 'eat--t-ui-cmd' to handle any OSC 51
sequence.
* eat.el (eat-term-set-parameter): Set 'ui-cmd-fn' slot of
terminal when 'ui-command-function' is set.
* eat.el (eat-term-cwd): Remove function.
* eat.el (eat-term-prompt-start-function)
(eat-term-prompt-end-function, eat-term-cmd-start-function)
(eat-term-cont-prompt-start-function)
(eat-term-cont-prompt-end-function, eat-term-set-cmd-function)
(eat-term-cmd-finish-function): Remove generalized variables.
* eat.el (eat-term-send-string): New function.
* eat.el (eat-send-string-as-yank): Rename to
'eat-term-send-string-as-yank'.
All callers changed.
* eat.el (eat--set-cwd-uic, eat--post-cont-prompt): New
function.
* eat.el (eat--pre-prompt, eat--post-prompt, eat--set-cmd)
(eat--pre-cmd, eat--set-cmd-status): Remove unused first
argument.
All callers changed.
* eat.el (eat--get-shell-history, eat--handle-uic): New
function.
* eat.el (eat-prompt-mode-map): New variable.
* eat.el (eat-emacs-mode, eat-semi-char-mode, eat-char-mode):
Handle the case when prompt mode is active.
* eat.el (eat--prompt-mode-previous-mode): New variable.
* eat.el (eat--prompt-mode): New non-interactive minor mode.
* eat.el (eat-prompt-send-default, eat-prompt-send)
(eat-prompt-newline, eat-prompt-delchar-or-eof)
(eat-prompt-send-interrupt): New command.
* eat.el (eat--prompt-input-ring, eat--prompt-input-ring-index)
(eat--prompt-stored-incomplete-input)
(eat--prompt-matching-input-from-input-string): New variable.
* eat.el (eat--prompt-populate-input-ring)
(eat--prompt-reset-input-ring-vars, eat--prompt-ask-for-regexp-arg)
(eat--prompt-search-arg, eat--prompt-search-start)
(eat--prompt-prev-input-string, eat--prompt-prev-matching-input-str)
(eat--prompt-delete-input, eat--prompt-prev-matching-input-str-pos):
New function.
* eat.el (eat-prompt-previous-input, eat-prompt-next-input)
(eat-prompt-restore-input, eat-prompt-previous-matching-input)
(eat-prompt-next-matching-input, eat-prompt-find-input)
(eat-prompt-previous-matching-input-from-input)
(eat-prompt-next-matching-input-from-input): New command.
* eat.el (eat-mode): Make 'eat--prompt-mode-previous-mode',
'eat--prompt-input-ring', 'eat--prompt-input-ring-index',
'eat--prompt-stored-incomplete-input' and
'eat--prompt-matching-input-from-input-string' buffer-local.
Record undo information if
'eat-enable-native-shell-prompt-editing' is enabled.  Set
'mode-line-process' properly so that prompt mode is shown when
enabled.
* eat.el (eat--process-output-queue): Remove any narrowing
temporarily when called.  Don't
* eat.el (eat--sentinel): Disable prompt mode.  Also fix the
bug where the point centers when the program exits, instead of
going to the end of buffer.
* eat.el (eat-exec): Don't set removed generalized variables
'eat-term-prompt-start-function', 'eat-term-set-cmd-function',
'eat-term-prompt-end-function', 'eat-term-cmd-start-function'
and 'eat-term-cmd-finish-function'.  Set terminal parameter
'ui-command-function' to 'eat--handle-uic'.
* eat.el (eat--eshell-handle-uic): New function.
* eat.el (eat--eshell-output-filter): Let-bind
'inhibit-read-only' only for required parts.
* eat.el (eat--eshell-setup-proc-and-term): Set terminal
parameter 'ui-command-function' to 'eat--eshell-handle-uic'.
* eat.el (eat--eshell-sentinel): Fix the bug where the point
centers when the program exits, instead of going to the end of
buffer.
* integration/bash (__eat_enable_integration): Send shell
history.

integration/bash

@@ -102,6 +102,17 @@ __eat_enable_integration ()
   done
   # Step 2.2: Assign the first element.
   PROMPT_COMMAND[0]=__eat_before_prompt_command
+  # Send the history, for native shell prompt.
+  printf '\e]51;e;I;0;%s;%s\e\\' \
+         "$(printf "%s" "$HOSTNAME" | base64)" \
+         "$(printf "%s" "$HISTFILE" | base64)"
+  local REPLY
+  IFS=$';\e' read -r -s -t 10 -d "\\" -a REPLY
+  if test "${REPLY[4]}" != 0
+  then
+    printf '\e]51;e;I;1;%s\e\\' \
+           "$(tail -n "${REPLY[4]}" "$HISTFILE" | base64)"
+  fi
 }
 
 # Enable.