org-mode-mirror/lisp/ob-ref.el

;;; ob-ref.el --- org-babel functions for referencing external data

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

;; Author: Eric Schulte, Dan Davison
;; Keywords: literate programming, reproducible research
;; 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:

;; Functions for referencing data from the header arguments of a
;; org-babel block.  The syntax of such a reference should be

;;   #+VAR: variable-name=file:resource-id

;; - variable-name :: the name of the variable to which the value
;;                    will be assigned

;; - file :: path to the file containing the resource, or omitted if
;;           resource is in the current file

;; - resource-id :: the id or name of the resource

;; So an example of a simple src block referencing table data in the
;; same file would be

;;  #+TBLNAME: sandbox
;;  | 1 |       2 | 3 |
;;  | 4 | org-babel | 6 |
;;
;;  #+begin_src emacs-lisp :var table=sandbox
;;    (message table)
;;  #+end_src

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

(declare-function org-remove-if-not "org" (predicate seq))
(declare-function org-at-table-p "org" (&optional table-type))

(defun org-babel-ref-variables (params)
  "Convert PARAMS to variable names and values.
Takes a parameter alist, and return an alist of variable names,
and the emacs-lisp representation of the related value."
  (let ((assignments
	 (delq nil (mapcar (lambda (pair) (if (eq (car pair) :var) (cdr pair))) params)))
	(others
         (delq nil (mapcar (lambda (pair) (unless (eq :var (car pair)) pair)) params))))
    (mapcar (lambda (assignment) (org-babel-ref-parse assignment)) assignments)))

(defvar org-babel-ref-split-regexp
  "[ \f\t\n\r\v]*\\(.+?\\)[ \f\t\n\r\v]*=[ \f\t\n\r\v]*\\(.+\\)[ \f\t\n\r\v]*")

(defun org-babel-ref-parse (assignment &optional params)
  "Parse a variable ASSIGNMENT in a header argument.
If the right hand side of the assignment has a literal value
return that value, otherwise interpret as a reference to an
external resource and find it's value using
`org-babel-ref-resolve-reference'.  Return a list with two
elements.  The first element of the list will be the name of the
variable, and the second will be an emacs-lisp representation of
the value of the variable."
  (if (string-match org-babel-ref-split-regexp assignment)
      (let ((var (match-string 1 assignment))
            (ref (match-string 2 assignment)))
        (cons (intern var)
	      ((lambda (val)
		 (if (equal :ob-must-be-reference val)
		     (org-babel-ref-resolve-reference ref params)
		   val)) (org-babel-ref-literal ref))))))

(defun org-babel-ref-literal (ref)
  "Return the value of REF if it is a literal value.
Determine if the right side of a header argument variable
assignment is a literal value or is a reference to some external
resource.  REF should be a string of the right hand side of the
assignment.  If REF is literal then return it's value, otherwise
return nil."
  (let ((out (org-babel-read ref)))
    (if (equal out ref)
        (if (string-match "^\".+\"$" ref)
            (read ref)
	  :ob-must-be-reference)
      out)))

(defvar org-babel-library-of-babel)
(defun org-babel-ref-resolve-reference (ref &optional params)
  "Resolve the reference REF and return its value."
  (save-excursion
    (let ((case-fold-search t)
          type args new-refere new-referent result lob-info split-file split-ref
          index index-row index-col)
      ;; if ref is indexed grab the indices -- beware nested indicies
      (when (and (string-match "\\[\\(.+\\)\\]" ref)
		 (let ((str (substring ref 0 (match-beginning 0))))
		   (= (length (org-remove-if-not
			       (lambda (el) (equal ?( el)) (string-to-list "((eric))")))
		      (length (org-remove-if-not
			       (lambda (el) (equal ?) el)) (string-to-list "((eric))"))))))
        (setq index (match-string 1 ref))
        (setq ref (substring ref 0 (match-beginning 0))))
      ;; assign any arguments to pass to source block
      (when (string-match "^\\(.+?\\)\(\\(.*\\)\)$" ref)
        (setq new-refere (match-string 1 ref))
        (setq new-referent (match-string 2 ref))
        ;; (message "new-refere=%S, new-referent=%S" new-refere new-referent) ;; debugging
        (when (> (length new-refere) 0)
          (if (> (length new-referent) 0)
              (setq args (mapcar (lambda (ref) (cons :var ref))
                                 (org-babel-ref-split-args new-referent))))
          ;; (message "args=%S" args) ;; debugging
          (setq ref new-refere)))
      (when (string-match "^\\(.+\\):\\(.+\\)$" ref)
        (setq split-file (match-string 1 ref))
        (setq split-ref (match-string 2 ref))
        (find-file split-file) (setq ref split-ref))
      (save-restriction
	(widen)
	(goto-char (point-min))
	(if (let ((result_regexp (concat "^[ \t]*#\\+\\(TBLNAME\\|RESNAME\\|RESULTS\\):[ \t]*"
					 (regexp-quote ref) "[ \t]*$"))
		  (regexp (concat org-babel-src-name-regexp
				  (regexp-quote ref) "\\(\(.*\)\\)?" "[ \t]*$")))
	      ;; goto ref in the current buffer
	      (or (and (not args)
		       (or (re-search-forward result_regexp nil t)
			   (re-search-backward result_regexp nil t)))
		  (re-search-forward regexp nil t)
		  (re-search-backward regexp nil t)
		  ;; check the Library of Babel
		  (setq lob-info (cdr (assoc (intern ref) org-babel-library-of-babel)))))
	    (unless lob-info (goto-char (match-beginning 0)))
	  ;; ;; TODO: allow searching for names in other buffers
	  ;; (setq id-loc (org-id-find ref 'marker)
	  ;;       buffer (marker-buffer id-loc)
	  ;;       loc (marker-position id-loc))
	  ;; (move-marker id-loc nil)
	  (error "reference '%s' not found in this buffer" ref))
	(if lob-info
	    (setq type 'lob)
	  (while (not (setq type (org-babel-ref-at-ref-p)))
	    (forward-line 1)
	    (beginning-of-line)
	    (if (or (= (point) (point-min)) (= (point) (point-max)))
		(error "reference not found"))))
	(setq params (org-babel-merge-params params args '((:results . "silent"))))
	(setq result
	      (case type
		('results-line (org-babel-read-result))
		('table (org-babel-read-table))
		('file (org-babel-read-link))
		('source-block (org-babel-execute-src-block nil nil params))
		('lob (org-babel-execute-src-block nil lob-info params))))
	(if (symbolp result)
	    (format "%S" result)
	  (if (and index (listp result))
	      (org-babel-ref-index-list index result)
	    result))))))

(defun org-babel-ref-index-list (index lis)
  "Return the subset of LIS indexed by INDEX.
If INDEX is separated by ,s then each PORTION is assumed to index
into the next deepest nesting or dimension.  A valid PORTION can
consist of either an integer index, or two integers separated by
a : in which case the entire range is returned."
  (if (string-match "^,?\\([^,]+\\)" index)
      (let ((length (length lis))
            (portion (match-string 1 index))
            (remainder (substring index (match-end 0))))
        (flet ((wrap (num) (if (< num 0) (+ length num) num))
               (open (lis) (if (and (listp lis) (= (length lis) 1)) (car lis) lis)))
          (open
           (mapcar
            (lambda (sub-lis) (org-babel-ref-index-list remainder sub-lis))
            (if (string-match "\\(\\([-[:digit:]]+\\):\\([-[:digit:]]+\\)\\|\*\\)"
                              portion)
                (mapcar (lambda (n) (nth n lis))
                        (apply 'number-sequence
                               (if (match-string 2 portion)
                                   (list
                                    (wrap (string-to-number (match-string 2 portion)))
                                    (wrap (string-to-number (match-string 3 portion))))
                                 (list (wrap 0) (wrap -1)))))
              (list (nth (wrap (string-to-number portion)) lis)))))))
    lis))

(defun org-babel-ref-split-args (arg-string)
  "Split ARG-STRING into top-level arguments of balanced parenthesis."
  (let ((index 0) (depth 0) (buffer "") holder return)
    ;; crawl along string, splitting at any ","s which are on the top level
    (while (< index (length arg-string))
      (setq holder (substring arg-string index (+ 1 index)))
      (setq buffer (concat buffer holder))
      (setq index (+ 1 index))
      (cond
       ((string= holder ",")
        (when (= depth 0)
          (setq return (reverse (cons (substring buffer 0 -1) return)))
          (setq buffer "")))
       ((or (string= holder "(") (string= holder "[")) (setq depth (+ depth 1)))
       ((or (string= holder ")") (string= holder "]")) (setq depth (- depth 1)))))
    (mapcar #'org-babel-trim (reverse (cons buffer return)))))

(defvar org-bracket-link-regexp)
(defun org-babel-ref-at-ref-p ()
  "Return the type of reference located at point.
Return nil if none of the supported reference types are found.
Supported reference types are tables and source blocks."
  (cond ((org-at-table-p) 'table)
        ((looking-at "^[ \t]*#\\+BEGIN_SRC") 'source-block)
        ((looking-at org-bracket-link-regexp) 'file)
        ((looking-at org-babel-result-regexp) 'results-line)))

(provide 'ob-ref)

;; arch-tag: ace4a4f4-ea38-4dac-8fe6-6f52fcc43b6d

;;; ob-ref.el ends here