;;; litorgy-exp.el --- Exportation of litorgy source blocks

;; 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:

;; for more information see the comments in litorgy.el

;;; Code:
(require 'litorgy)
(require 'org-exp-blocks)
(add-to-list 'org-export-blocks '(src litorgy-exp-src-blocks))
(add-to-list 'org-export-interblocks '(src litorgy-exp-inline-src-blocks))

(defun litorgy-exp-src-blocks (body &rest headers)
  "Process src block for export.  Depending on the 'export'
headers argument in replace the source code block with...

both ---- the default, display the code and the results

code ---- display the code inside the block but do not process

results - process the block and replace it with the results of
          execution

none ----- do not display either code or results upon export"
  (interactive)
  (unless headers (error "litorgy can't process a source block without knowing the source code"))
  (message "litorgy processing...")
  (let ((lang (car headers))
        (params (litorgy-parse-header-arguments (mapconcat #'identity (cdr headers) " "))))
    (litorgy-exp-do-export lang body params)))

(defun litorgy-exp-inline-src-blocks (start end)
  "Process inline src blocks between START and END for export.
See `litorgy-exp-src-blocks' for export options, currently the
options and are taken from `litorgy-inline-header-args'."
  (interactive)
  (save-excursion
    (goto-char start)
    (while (and (< (point) end) (re-search-forward litorgy-inline-src-block-regexp end t))
      (let* ((info (save-match-data (litorgy-parse-inline-src-block-match)))
             (replacement (save-match-data
                            (litorgy-exp-do-export (first info) (second info) (third info) t))))
        (setf end (+ end (- (length replacement)
                            (+ 6 (length (first info)) (length (second info))))))
        (replace-match replacement t t)))))

(defun litorgy-exp-do-export (lang body params &optional inline)
  (case (intern (or (cdr (assoc :exports params)) "both"))
          ('none "")
          ('code (litorgy-exp-code body lang params inline))
          ('results (litorgy-exp-results body lang params inline))
          ('both (concat (litorgy-exp-code body lang params inline)
                     "\n\n"
                     (litorgy-exp-results body lang params inline)))))

(defun litorgy-exp-code (body lang params &optional inline)
  (if inline
      (format "=%s=" body)
    (format "#+BEGIN_SRC %s\n%s%s\n#+END_SRC" lang body
            (if (string-match "\n$" body) "" "\n"))))

(defun litorgy-exp-results (body lang params &optional inline)
  (let* ((cmd (intern (concat "litorgy-execute:" lang)))
         (result (funcall cmd body params))
         (result-as-org (litorgy-result-to-org-string result)))
    (if inline
        (format "=%s=" result)
      (if (stringp result)
          (format "#+BEGIN_EXAMPLE\n%s%s\n#+END_EXAMPLE" result
                  (if (string-match "\n$" body) "" "\n"))
        result-as-org))))

(provide 'litorgy-exp)
;;; litorgy-exp.el ends here