;;; org-babel-gnuplot.el --- org-babel functions for gnuplot 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 gnuplot source code.
;;
;; This differs from most standard languages in that
;;
;; 1) we are generally only going to return results of type "file"
;;
;; 2) we are adding the "file" and "cmdline" header arguments

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

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

(add-to-list 'org-babel-tangle-langs '("gnuplot" "gnuplot"))

(defvar org-babel-default-header-args:gnuplot '((:results . "file") (:exports . "results"))
  "Default arguments to use when evaluating a gnuplot source block.")

(defvar org-babel-gnuplot-timestamp-fmt nil)

(defun org-babel-execute:gnuplot (body params)
  "Execute a block of Gnuplot code with org-babel.  This function is
called by `org-babel-execute-src-block' via multiple-value-bind."
  (message "executing Gnuplot source code block")
  (let* (;; should be able to lose the next two lines but I don't know
	 ;; how to test it so not doing it now.
	 (vars (org-babel-ref-variables params))
         (result-params (split-string (or (cdr (assoc :results params)) "")))
         (out-file (cdr (assoc :file params)))
         (cmdline (cdr (assoc :cmdline params)))
         (in-file (make-temp-file "org-babel-ditaa")))
    ;; insert variables into code body
    (mapc
     (lambda (pair)
       (message "resolving %S" pair) ;; debugging
       (setq body
             (replace-regexp-in-string
              (regexp-quote (format "%s" (car pair)))
              (if (listp (cdr pair))
                  (org-babel-gnuplot-table-to-data
                   (cdr pair) (make-temp-file "org-babel-gnuplot") params)
                (cdr pair)) body)))
     vars)
    (with-temp-buffer ;; evaluate the code body with gnuplot
      (insert (concat body "\n"))
      (gnuplot-mode)
      (gnuplot-send-buffer-to-gnuplot))
    out-file))

(defun org-babel-prep-session:gnuplot (session params))

(defun org-babel-gnuplot-quote-timestamp-field (s)
  "Convert field S from timestamp to Unix time and export to gnuplot."
  (format-time-string org-babel-gnuplot-timestamp-fmt (org-time-string-to-time s)))

(defun org-babel-gnuplot-quote-tsv-field (s)
  "Quote field S for export to gnuplot."
  (unless (stringp s)
    (setq s (format "%s" s)))
  (if (string-match org-table-number-regexp s) s
    (if (string-match org-ts-regexp3 s)
	(org-babel-gnuplot-quote-timestamp-field s)
      (concat "\"" (mapconcat 'identity (split-string s "\"") "\"\"") "\""))))

(defun org-babel-gnuplot-table-to-data (table data-file params)
  "Export TABLE to DATA-FILE in a format readable by gnuplot.
Pass PARAMS through to `orgtbl-to-generic' when exporting TABLE."
  (with-temp-file data-file
    (message "table = %S" table)
    (make-local-variable 'org-babel-gnuplot-timestamp-fmt)
    (setq org-babel-gnuplot-timestamp-fmt (or
                                           (plist-get params :timefmt)
                                           "%Y-%m-%d-%H:%M:%S"))
    (insert (orgtbl-to-generic
	     table
	     (org-combine-plists
	      '(:sep "\t" :fmt org-babel-gnuplot-quote-tsv-field)
	      params))))
  data-file)

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