(provide 'em-rebind)
(eval-when-compile (require 'esh-maint))
(defgroup eshell-rebind nil
"This module allows for special keybindings that only take effect
while the point is in a region of input text. By default, it binds
C-a to move to the beginning of the input text (rather than just the
beginning of the line), and C-p and C-n to move through the input
history, C-u kills the current input text, etc. It also, if
`eshell-confine-point-to-input' is non-nil, does not allow certain
commands to cause the point to leave the input area, such as
`backward-word', `previous-line', etc. This module intends to mimic
the behavior of normal shells while the user editing new input text."
:tag "Rebind keys at input"
:group 'eshell-module)
(defcustom eshell-rebind-load-hook '(eshell-rebind-initialize)
"*A list of functions to call when loading `eshell-rebind'."
:type 'hook
:group 'eshell-rebind)
(defcustom eshell-rebind-keys-alist
'(([(control ?a)] . eshell-bol)
([home] . eshell-bol)
([(control ?d)] . eshell-delchar-or-maybe-eof)
([backspace] . eshell-delete-backward-char)
([delete] . eshell-delete-backward-char)
([(control ?w)] . backward-kill-word)
([(control ?u)] . eshell-kill-input))
"*Bind some keys differently if point is in input text."
:type '(repeat (cons (vector :tag "Keys to bind"
(repeat :inline t sexp))
(function :tag "Command")))
:group 'eshell-rebind)
(defcustom eshell-confine-point-to-input t
"*If non-nil, do not allow the point to leave the current input.
This is more difficult to do nicely in Emacs than one might think.
Basically, the `point-left' attribute is added to the input text, and
a function is placed on that hook to take the point back to
`eshell-last-output-end' every time the user tries to move away. But
since there are many cases in which the point _ought_ to move away
\(for programmatic reasons), the variable
`eshell-cannot-leave-input-list' defines commands which are affected
from this rule. However, this list is by no means as complete as it
probably should be, so basically all one can hope for is that other
people will left the point alone in the Eshell buffer. Sigh."
:type 'boolean
:group 'eshell-rebind)
(defcustom eshell-error-if-move-away t
"*If non-nil, consider it an error to try to move outside current input.
This is default behavior of shells like bash."
:type 'boolean
:group 'eshell-rebind)
(defcustom eshell-remap-previous-input t
"*If non-nil, remap input keybindings on previous prompts as well."
:type 'boolean
:group 'eshell-rebind)
(defcustom eshell-cannot-leave-input-list
'(beginning-of-line-text
beginning-of-line
move-to-column
move-to-column-force
move-to-left-margin
move-to-tab-stop
forward-char
backward-char
delete-char
delete-backward-char
backward-delete-char
backward-delete-char-untabify
kill-paragraph
backward-kill-paragraph
kill-sentence
backward-kill-sentence
kill-sexp
backward-kill-sexp
kill-word
backward-kill-word
kill-region
forward-list
backward-list
forward-page
backward-page
forward-point
forward-paragraph
backward-paragraph
backward-prefix-chars
forward-sentence
backward-sentence
forward-sexp
backward-sexp
forward-to-indentation
backward-to-indentation
backward-up-list
forward-word
backward-word
forward-line
previous-line
next-line
forward-visible-line
forward-comment
forward-thing)
"*A list of commands that cannot leave the input area."
:type '(repeat function)
:group 'eshell-rebind)
(defvar eshell-input-keymap)
(defvar eshell-previous-point)
(defvar eshell-lock-keymap)
(defun eshell-rebind-initialize ()
"Initialize the inputing code."
(unless eshell-non-interactive-p
(add-hook 'eshell-mode-hook 'eshell-setup-input-keymap nil t)
(make-local-variable 'eshell-previous-point)
(add-hook 'pre-command-hook 'eshell-save-previous-point nil t)
(make-local-variable 'overriding-local-map)
(add-hook 'post-command-hook 'eshell-rebind-input-map nil t)
(set (make-local-variable 'eshell-lock-keymap) nil)
(define-key eshell-command-map [(meta ?l)] 'eshell-lock-local-map)))
(defun eshell-lock-local-map (&optional arg)
"Lock or unlock the current local keymap.
Within a prefix arg, set the local keymap to its normal value, and
lock it at that."
(interactive "P")
(if (or arg (not eshell-lock-keymap))
(progn
(use-local-map eshell-mode-map)
(setq eshell-lock-keymap t)
(message "Local keymap locked in normal mode"))
(use-local-map eshell-input-keymap)
(setq eshell-lock-keymap nil)
(message "Local keymap unlocked: obey context")))
(defun eshell-save-previous-point ()
"Save the location of point before the next command is run."
(setq eshell-previous-point (point)))
(defsubst eshell-point-within-input-p (pos)
"Test whether POS is within an input range."
(let (begin)
(or (and (>= pos eshell-last-output-end)
eshell-last-output-end)
(and eshell-remap-previous-input
(setq begin
(save-excursion
(eshell-bol)
(and (not (bolp)) (point))))
(>= pos begin)
(<= pos (line-end-position))
begin))))
(defun eshell-rebind-input-map ()
"Rebind the input keymap based on the location of the cursor."
(ignore-errors
(unless eshell-lock-keymap
(if (eshell-point-within-input-p (point))
(use-local-map eshell-input-keymap)
(let (begin)
(if (and eshell-confine-point-to-input
(setq begin
(eshell-point-within-input-p eshell-previous-point))
(memq this-command eshell-cannot-leave-input-list))
(progn
(use-local-map eshell-input-keymap)
(goto-char begin)
(if (and eshell-error-if-move-away
(not (eq this-command 'kill-region)))
(beep)))
(use-local-map eshell-mode-map)))))))
(defun eshell-setup-input-keymap ()
"Setup the input keymap to be used during input editing."
(make-local-variable 'eshell-input-keymap)
(setq eshell-input-keymap (make-sparse-keymap))
(set-keymap-parent eshell-input-keymap eshell-mode-map)
(let ((bindings eshell-rebind-keys-alist))
(while bindings
(define-key eshell-input-keymap (caar bindings)
(cdar bindings))
(setq bindings (cdr bindings)))))
(defun eshell-delete-backward-char (n &optional killflag)
"Delete the last character, unless it's part of the output."
(interactive "P")
(let ((count (prefix-numeric-value n)))
(if (eshell-point-within-input-p (- (point) count))
(delete-backward-char count n)
(beep))))
(defun eshell-delchar-or-maybe-eof (arg)
"Delete ARG characters forward or send an EOF to subprocess.
Sends an EOF only if point is at the end of the buffer and there is no
input."
(interactive "p")
(let ((proc (eshell-interactive-process)))
(if (eobp)
(cond
((/= (point) eshell-last-output-end)
(beep))
(proc
(process-send-eof))
(t
(eshell-life-is-too-much)))
(eshell-delete-backward-char (- arg)))))