;;; ob-comint.el --- org-babel functions for interaction with comint buffers

;; Copyright (C) 2009, 2010  Free Software Foundation, Inc.

;; Author: Eric Schulte
;; Keywords: literate programming, reproducible research, comint
;; Homepage: http://orgmode.org
;; Version: 0.01

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; These functions build on comint to ease the sending and receiving
;; of commands and results from comint buffers.

;; Note that the buffers in this file are analogous to sessions in
;; org-babel at large.

;;; Code:
(require 'ob)
(require 'comint)
(eval-when-compile (require 'cl))

(defun org-babel-comint-buffer-livep (buffer)
  "Check if BUFFER is a comint buffer with a live process."
  (let ((buffer (if buffer (get-buffer buffer))))
    (and buffer (buffer-live-p buffer) (get-buffer-process buffer) buffer)))

(defmacro org-babel-comint-in-buffer (buffer &rest body)
  "Check BUFFER with `org-babel-comint-buffer-livep' then execute
body inside the protection of `save-window-excursion' and
`save-match-data'."
  (declare (indent 1))
  `(save-excursion
     (save-match-data
       (unless (org-babel-comint-buffer-livep ,buffer)
         (error (format "buffer %s doesn't exist or has no process" ,buffer)))
       (set-buffer ,buffer)
       ,@body)))

(defmacro org-babel-comint-with-output (meta &rest body)
  "Evaluate BODY in BUFFER, wait until EOE-INDICATOR appears in
output, then return all process output.  If REMOVE-ECHO and
FULL-BODY are present and non-nil, then strip echo'd body from
the returned output.  META should be a list containing the
following where the last two elements are optional.

 (BUFFER EOE-INDICATOR REMOVE-ECHO FULL-BODY)

This macro ensures that the filter is removed in case of an error
or user `keyboard-quit' during execution of body."
  (declare (indent 1))
  (let ((buffer (car meta))
	(eoe-indicator (cadr meta))
	(remove-echo (cadr (cdr meta)))
	(full-body (cadr (cdr (cdr meta)))))
    `(org-babel-comint-in-buffer ,buffer
       (let ((string-buffer "") dangling-text raw)
	 (flet ((my-filt (text)
			 (setq string-buffer (concat string-buffer text))))
	   ;; setup filter
	   (add-hook 'comint-output-filter-functions 'my-filt)
	   (unwind-protect
	       (progn
		 ;; got located, and save dangling text
		 (goto-char (process-mark (get-buffer-process (current-buffer))))
		 (let ((start (point))
		       (end (point-max)))
		   (setq dangling-text (buffer-substring start end))
		   (delete-region start end))
		 ;; pass FULL-BODY to process
		 ,@body
		 ;; wait for end-of-evaluation indicator
		 (while (progn
			  (goto-char comint-last-input-end)
			  (not (save-excursion
				 (and (re-search-forward
				       comint-prompt-regexp nil t)
				      (re-search-forward
				       (regexp-quote ,eoe-indicator) nil t)))))
		   (accept-process-output (get-buffer-process (current-buffer)))
		   ;; thought the following this would allow async
		   ;; background running, but I was wrong...
		   ;; (run-with-timer .5 .5 'accept-process-output
		   ;; 		 (get-buffer-process (current-buffer)))
		   )
		 ;; replace cut dangling text
		 (goto-char (process-mark (get-buffer-process (current-buffer))))
		 (insert dangling-text))
	     ;; remove filter
	     (remove-hook 'comint-output-filter-functions 'my-filt)))
	 ;; remove echo'd FULL-BODY from input
	 (if (and ,remove-echo ,full-body
		  (string-match
		   (replace-regexp-in-string
		    "\n" "[\r\n]+" (regexp-quote ,full-body))
		   string-buffer))
	     (setq raw (substring string-buffer (match-end 0))))
	 (split-string string-buffer comint-prompt-regexp)))))

(defun org-babel-comint-input-command (buffer cmd)
  "Pass CMD to BUFFER  The input will not be echoed."
  (org-babel-comint-in-buffer buffer
    (goto-char (process-mark (get-buffer-process buffer)))
    (insert cmd)
    (comint-send-input)
    (org-babel-comint-wait-for-output buffer)))

(defun org-babel-comint-wait-for-output (buffer)
  "Wait until output arrives from BUFFER.  Note: this is only
safe when waiting for the result of a single statement (not large
blocks of code)."
  (org-babel-comint-in-buffer buffer
    (while (progn
             (goto-char comint-last-input-end)
             (not (and (re-search-forward comint-prompt-regexp nil t)
                       (goto-char (match-beginning 0))
                       (string= (face-name (face-at-point))
                                "comint-highlight-prompt"))))
      (accept-process-output (get-buffer-process buffer)))))

(provide 'ob-comint)

;; arch-tag: 9adddce6-0864-4be3-b0b5-6c5157dc7889

;;; ob-comint.el ends here