ob-octave.el: Add graphical output

* lisp/ob-octave.el: add graphical output to png file

    * testing/examples/ob-octave-test.org: add a test for graphical
      output, and a test for session

lisp/ob-octave.el

@@ -86,13 +86,24 @@ end")
 	  (org-babel-expand-body:generic
 	   body params (org-babel-variable-assignments:octave params)))
 	 (result (org-babel-octave-evaluate
-		  session full-body result-type matlabp)))
-    (org-babel-reassemble-table
-     result
-     (org-babel-pick-name
-      (cdr (assoc :colname-names params)) (cdr (assoc :colnames params)))
-     (org-babel-pick-name
-      (cdr (assoc :rowname-names params)) (cdr (assoc :rownames params))))))
+		  session
+		  (if (org-babel-octave-graphical-output-file params)
+		      (mapconcat 'identity
+				 (list
+				  "set (0, \"defaultfigurevisible\", \"off\");"
+				  full-body
+				  (format "print -dpng %s" (org-babel-octave-graphical-output-file params)))
+				 "\n")
+		    full-body)
+		  result-type matlabp)))
+    (if (org-babel-octave-graphical-output-file params)
+	nil
+      (org-babel-reassemble-table
+       result
+       (org-babel-pick-name
+	(cdr (assoc :colname-names params)) (cdr (assoc :colnames params)))
+       (org-babel-pick-name
+	(cdr (assoc :rowname-names params)) (cdr (assoc :rownames params)))))))
 
 (defun org-babel-prep-session:matlab (session params)
   "Prepare SESSION according to PARAMS."
@@ -259,6 +270,11 @@ This removes initial blank and comment lines and then calls
       (match-string 1 string)
     string))
 
+(defun org-babel-octave-graphical-output-file (params)
+  "Name of file to which maxima should send graphical output."
+  (and (member "graphics" (cdr (assq :result-params params)))
+       (cdr (assq :file params))))
+
 (provide 'ob-octave)
 
 

testing/examples/ob-octave-test.org

@@ -43,3 +43,13 @@ Input elisp nil
 #+begin_src octave :exports results :results silent :var s='nil
 ans = s
 #+end_src
+
+
+* Graphical tests
+#+begin_src octave :results graphics :file chart.png
+sombrero;
+#+end_src
+
+#+begin_src octave :session
+sombrero;
+#+end_src