;;; org-babel-sh.el --- org-babel functions for shell evaluation

;; Copyright (C) 2009 Eric Schulte

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

;;; License:

;; This program 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, or (at your option)
;; any later version.
;;
;; This program 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; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; Org-Babel support for evaluating shell source code.

;;; Code:
(require 'org-babel)
(require 'shell)

(org-babel-add-interpreter "sh")

(defun org-babel-execute:sh (body params)
  "Execute a block of Shell commands with org-babel.  This
function is called by `org-babel-execute-src-block'."
  (message "executing Shell source code block")
  (let* ((vars (org-babel-ref-variables params))
         (result-params (split-string (or (cdr (assoc :results params)) "")))
         (result-type (cond ((member "output" result-params) 'output)
                            ((member "value" result-params) 'value)
                            (t 'value)))
         (full-body (concat
                     (mapconcat ;; define any variables
                      (lambda (pair)
                        (format "%s=%s"
                                (car pair)
                                (org-babel-sh-var-to-sh (cdr pair))))
                      vars "\n") "\n" body "\n\n")) ;; then the source block body
         (session (org-babel-sh-initiate-session (cdr (assoc :session params))))
         (results (org-babel-sh-evaluate session full-body result-type)))
    (if (member "scalar" result-params)
        results
      (setq results (let ((tmp-file (make-temp-file "org-babel-shell")))
                      (with-temp-file tmp-file (insert results))
                      (org-babel-import-elisp-from-file tmp-file)))
      (if (and (member "vector" results) (not (listp results)))
          (list (list results))
        results))))

(defun org-babel-prep-session:sh (session params)
  "Prepare SESSION according to the header arguments specified in PARAMS."
  (let* ((session (org-babel-sh-initiate-session session))
         (vars (org-babel-ref-variables params))
         (var-lines (mapcar ;; define any variables
                     (lambda (pair)
                       (format "%s=%s"
                               (car pair)
                               (org-babel-sh-var-to-sh (cdr pair))))
                     vars)))
    (org-babel-comint-in-buffer session
      (mapc (lambda (var)
              (insert var) (comint-send-input nil t)
              (org-babel-comint-wait-for-output session)) var-lines))))

;; helper functions

(defun org-babel-sh-var-to-sh (var)
  "Convert an elisp var into a string of shell commands
specifying a var of the same value."
  (if (listp var)
      (concat "[" (mapconcat #'org-babel-sh-var-to-sh var ", ") "]")
    (format "%S" var)))

(defun org-babel-sh-table-or-results (results)
  "If the results look like a table, then convert them into an
Emacs-lisp table, otherwise return the results as a string."
  (org-babel-read
   (if (string-match "^\\[.+\\]$" results)
       (org-babel-read
        (replace-regexp-in-string
         "\\[" "(" (replace-regexp-in-string
                    "\\]" ")" (replace-regexp-in-string
                               ", " " " (replace-regexp-in-string
                                         "'" "\"" results)))))
     results)))

(defvar org-babel-sh-buffers '(:default . nil))

(defun org-babel-sh-session-buffer (session)
  (cdr (assoc session org-babel-sh-buffers)))

(defun org-babel-sh-initiate-session-by-key (&optional session)
  "If there is not a current inferior-process-buffer in SESSION
then create.  Return the initialized session."
  (save-window-excursion
    (let* ((session (if session (intern session) :default))
           (sh-buffer (org-babel-sh-session-buffer session))
           (newp (not (org-babel-comint-buffer-livep sh-buffer))))
      (if (and sh-buffer (get-buffer sh-buffer) (not (buffer-live-p sh-buffer)))
          (setq sh-buffer nil))
      (shell sh-buffer)
      (when newp
        (setq sh-buffer (current-buffer))
        (org-babel-comint-wait-for-output sh-buffer))
      (setq org-babel-sh-buffers (cons (cons session sh-buffer) (assq-delete-all session org-babel-sh-buffers)))
      session)))

(defun org-babel-sh-initiate-session (&optional session)
  (org-babel-sh-session-buffer (org-babel-sh-initiate-session-by-key session)))

(defvar org-babel-sh-eoe-indicator "echo 'org_babel_sh_eoe'"
  "Used to indicate that evaluation is has completed.")
(defvar org-babel-sh-eoe-output "org_babel_sh_eoe"
  "Used to indicate that evaluation is has completed.")

(defun org-babel-sh-evaluate (buffer body &optional result-type)
  "Pass BODY to the Shell process in BUFFER.  If RESULT-TYPE equals
'output then return a list of the outputs of the statements in
BODY, if RESULT-TYPE equals 'value then return the value of the
last statement in BODY."
  (let* ((full-body (mapconcat #'org-babel-chomp
                               (list body org-babel-sh-eoe-indicator) "\n"))
         (raw (org-babel-comint-with-output buffer org-babel-sh-eoe-output nil
                (insert full-body) (comint-send-input nil t)))
         (results (cdr (member org-babel-sh-eoe-output
                                    (reverse (mapcar #'org-babel-sh-strip-weird-long-prompt
                                                     (mapcar #'org-babel-trim raw)))))))
    ;; (message (replace-regexp-in-string "%" "%%" (format "processed-results=%S" results))) ;; debugging
    (or (case result-type
          (output (org-babel-trim (mapconcat #'org-babel-trim (reverse results) "\n")))
          (value (car results))
          (t (reverse results))) "")))

(defun org-babel-sh-strip-weird-long-prompt (string)
  (while (string-match "^% +[\r\n$]+ *" string)
    (setq string (substring string (match-end 0))))
  string)

(provide 'org-babel-sh)
;;; org-babel-sh.el ends here