org-mode/lisp/babel/ob-table.el

;;; ob-table.el --- integration for calling org-babel functions from tables

;; 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:

;; Should allow calling functions from org-mode tables using the
;; function `sbe' as so...
;; 
;; #+begin_src emacs-lisp :results silent
;; (defun fibbd (n) (if (< n 2) 1 (+ (fibbd (- n 1)) (fibbd (- n 2)))))
;; #+end_src
;; 
;; #+srcname: fibbd
;; #+begin_src emacs-lisp :var n=2 :results silent
;; (fibbd n)
;; #+end_src
;; 
;; | original | fibbd  |
;; |----------+--------|
;; |        0 |        |
;; |        1 |        |
;; |        2 |        |
;; |        3 |        |
;; |        4 |        |
;; |        5 |        |
;; |        6 |        |
;; |        7 |        |
;; |        8 |        |
;; |        9 |        |
;; #+TBLFM: $2='(sbe 'fibbd (n $1))

;;; Code:
(require 'ob)

(defun org-babel-table-truncate-at-newline (string)
  "If STRING ends in a newline character, then remove the newline
character and replace it with ellipses."
  (if (and (stringp string) (string-match "[\n\r]" string))
      (concat (substring string 0 (match-beginning 0)) "...")
    string))

(defmacro sbe (source-block &rest variables)
  "Return the results of calling SOURCE-BLOCK assigning every
variable in VARIABLES.  Each element of VARIABLES should be a two
element list, whose first element is the name of the variable and
second element is a string of its value.  The following call to
`sbe' would be equivalent to the following source code block.

 (sbe 'source-block (n $2) (m 3))

#+begin_src emacs-lisp :var results=source-block(n=val_at_col_2, m=3) :results silent
results
#+end_src

NOTE: by default string variable names are interpreted as
references to source-code blocks, to force interpretation of a
cell's value as a string, prefix the identifier with two \"$\"s
rather than a single \"$\" (i.e. \"$$2\" instead of \"$2\" in the
example above."
  (let ((variables (mapcar
                    (lambda (var)
                      (if (and (= 3 (length var)) (eq (nth 1 var) '$))
                          (list (car var) (format "\"%s\"" (last var)))
                        var))
                    variables)))
    (unless (stringp source-block) (setq source-block (symbol-name source-block)))
    (org-babel-table-truncate-at-newline ;; org-table cells can't be multi-line
     (if (and source-block (> (length source-block) 0))
         (let ((params
                (eval `(org-babel-parse-header-arguments
                        (concat ":var results="
                                ,source-block
                                "("
                                (mapconcat (lambda (var-spec)
                                             (format "%S=%s" (nth 0 var-spec) (nth 1 var-spec)))
                                           ',variables ", ")
                                ")")))))
           (org-babel-execute-src-block
            nil (list "emacs-lisp" "results"
                      (org-babel-merge-params '((:results . "silent")) params))))
       ""))))

(provide 'ob-table)
;;; ob-table.el ends here