(eval-when-compile
(require 'comint)
(require 'shell))
(defgroup dirtrack nil
"Directory tracking by watching the prompt."
:prefix "dirtrack-"
:group 'shell)
(defcustom dirtrack-list (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
"*List for directory tracking.
First item is a regexp that describes where to find the path in a prompt.
Second is a number, the regexp group to match. Optional third item is
whether the prompt is multi-line. If nil or omitted, prompt is assumed to
be on a single line."
:group 'dirtrack
:type '(sexp (regexp :tag "Prompt Expression")
(integer :tag "Regexp Group")
(boolean :tag "Multiline Prompt")
)
)
(make-variable-buffer-local 'dirtrack-list)
(defcustom dirtrack-debug nil
"*If non-nil, the function `dirtrack' will report debugging info."
:group 'dirtrack
:type 'boolean
)
(defcustom dirtrack-debug-buffer "*Directory Tracking Log*"
"Buffer to write directory tracking debug information."
:group 'dirtrack
:type 'string
)
(defcustom dirtrackp t
"*If non-nil, directory tracking via `dirtrack' is enabled."
:group 'dirtrack
:type 'boolean
)
(make-variable-buffer-local 'dirtrackp)
(defcustom dirtrack-directory-function
(if (memq system-type (list 'ms-dos 'windows-nt))
'dirtrack-windows-directory-function
'dirtrack-default-directory-function)
"*Function to apply to the prompt directory for comparison purposes."
:group 'dirtrack
:type 'function
)
(defcustom dirtrack-canonicalize-function
(if (memq system-type (list 'ms-dos 'windows-nt))
'downcase 'identity)
"*Function to apply to the default directory for comparison purposes."
:group 'dirtrack
:type 'function
)
(defcustom dirtrack-directory-change-hook nil
"Hook that is called when a directory change is made."
:group 'dirtrack
:type 'hook
)
(defun dirtrack-default-directory-function (dir)
"Return a canonical directory for comparison purposes.
Such a directory ends with a forward slash."
(let ((directory dir))
(if (not (char-equal ?/ (string-to-char (substring directory -1))))
(concat directory "/")
directory)))
(defun dirtrack-windows-directory-function (dir)
"Return a canonical directory for comparison purposes.
Such a directory is all lowercase, has forward-slashes as delimiters,
and ends with a forward slash."
(let ((directory dir))
(setq directory (downcase (dirtrack-replace-slash directory t)))
(if (not (char-equal ?/ (string-to-char (substring directory -1))))
(concat directory "/")
directory)))
(defconst dirtrack-forward-slash (regexp-quote "/"))
(defconst dirtrack-backward-slash (regexp-quote "\\"))
(defun dirtrack-replace-slash (string &optional opposite)
"Replace forward slashes with backwards ones.
If additional argument is non-nil, replace backwards slashes with
forward ones."
(let ((orig (if opposite
dirtrack-backward-slash
dirtrack-forward-slash))
(replace (if opposite
dirtrack-forward-slash
dirtrack-backward-slash))
(newstring string)
)
(while (string-match orig newstring)
(setq newstring (replace-match replace nil t newstring)))
newstring))
(defun dirtrack-toggle ()
"Enable or disable Dirtrack directory tracking in a shell buffer."
(interactive)
(setq dirtrackp (not dirtrackp))
(message "Directory tracking %s" (if dirtrackp "ON" "OFF")))
(defun dirtrack-debug-toggle ()
"Enable or disable Dirtrack debugging."
(interactive)
(setq dirtrack-debug (not dirtrack-debug))
(message "Directory debugging %s" (if dirtrack-debug "ON" "OFF"))
(and dirtrack-debug
(display-buffer (get-buffer-create dirtrack-debug-buffer))))
(defun dirtrack-debug-message (string)
(let ((buf (current-buffer))
(debug-buf (get-buffer-create dirtrack-debug-buffer))
)
(set-buffer debug-buf)
(goto-char (point-max))
(insert (concat string "\n"))
(set-buffer buf)
))
(defun dirtrack (input)
"Determine the current directory by scanning the process output for a prompt.
The prompt to look for is the first item in `dirtrack-list'.
You can toggle directory tracking by using the function `dirtrack-toggle'.
If directory tracking does not seem to be working, you can use the
function `dirtrack-debug-toggle' to turn on debugging output.
You can enable directory tracking by adding this function to
`comint-output-filter-functions'.
"
(if (null dirtrackp)
nil
(let (prompt-path
matched
(current-dir default-directory)
(dirtrack-regexp (nth 0 dirtrack-list))
(match-num (nth 1 dirtrack-list))
(multi-line (nth 2 dirtrack-list))
)
(if (eq (point) (point-min))
nil
(save-excursion
(setq matched (string-match dirtrack-regexp input)))
(if (null matched)
(and dirtrack-debug
(dirtrack-debug-message
(format
"Input `%s' failed to match regexp: %s"
input dirtrack-regexp)))
(setq prompt-path
(substring input
(match-beginning match-num) (match-end match-num)))
(if (not (> (length prompt-path) 0))
(and dirtrack-debug
(dirtrack-debug-message "Match is empty string"))
(setq prompt-path (funcall dirtrack-directory-function
prompt-path))
(setq current-dir (funcall dirtrack-canonicalize-function
current-dir))
(and dirtrack-debug
(dirtrack-debug-message
(format
"Prompt is %s\nCurrent directory is %s"
prompt-path current-dir)))
(if (or (string= current-dir prompt-path)
(string= current-dir
(abbreviate-file-name prompt-path)))
(and dirtrack-debug
(dirtrack-debug-message
(format "Not changing directory")))
(if (file-accessible-directory-p prompt-path)
(and (shell-process-cd prompt-path)
(run-hooks 'dirtrack-directory-change-hook)
dirtrack-debug
(dirtrack-debug-message
(format "Changing directory to %s" prompt-path)))
(error "Directory %s does not exist" prompt-path)))
)))))
input)
(provide 'dirtrack)