babel: matlab: detect end of evaluation under Emacs Link

Currently, this uses the presence of a temporary file to signal that
Matlab Emacs Link evaluation is not yet complete.

Emacs Link support added in collaboration with Christopher Long.

contrib/babel/lisp/langs/org-babel-matlab.el

@@ -55,6 +55,14 @@
   evaluation. This will use EmacsLink if (matlab-with-emacs-link)
   evaluates to a non-nil value.")
 
+(defvar org-babel-matlab-emacs-link-wrapper-method
+   "%s
+if ischar(ans), fid = fopen('%s', 'w'); fprintf(fid, '%%s\\n', ans); fclose(fid);
+else, save -ascii %s ans
+end
+delete('%s')
+")
+
 (defun org-babel-execute:matlab (body params)
   "Execute a block of matlab code with org-babel."
   (org-babel-execute:octave body params 'matlab))

contrib/babel/lisp/langs/org-babel-octave.el

@@ -155,6 +155,7 @@ value of the last statement in BODY, as elisp."
 
 (defun org-babel-octave-evaluate-session (session body result-type &optional matlabp)
   (let* ((tmp-file (make-temp-file "org-babel-results-"))
+	 (wait-file (make-temp-file "org-babel-matlab-emacs-link-wait-signal-"))
 	 (full-body
 	  (case result-type
 	    (output
@@ -162,14 +163,22 @@ value of the last statement in BODY, as elisp."
 	      #'org-babel-chomp
 	      (list body org-babel-octave-eoe-indicator) "\n"))
 	    (value
-	     (mapconcat
-	      #'org-babel-chomp
-	      (list (format org-babel-octave-wrapper-method body tmp-file tmp-file) org-babel-octave-eoe-indicator) "\n"))))
+	     (if (and matlabp org-babel-matlab-with-emacs-link)
+		 (concat
+		  (format org-babel-matlab-emacs-link-wrapper-method
+			  body tmp-file tmp-file wait-file) "\n")
+	       (mapconcat
+		#'org-babel-chomp
+		(list (format org-babel-octave-wrapper-method body tmp-file tmp-file)
+		      org-babel-octave-eoe-indicator) "\n")))))
 	 (raw (if (and matlabp org-babel-matlab-with-emacs-link)
 		  (save-window-excursion
 		    (with-temp-buffer
 		      (insert full-body)
+		      (write-region "" 'ignored wait-file nil nil nil 'excl)
 		      (matlab-shell-run-region (point-min) (point-max))
+		      (message "Waiting for Matlab Emacs Link")
+		      (while (file-exists-p wait-file) (sit-for 0.01))
 		      "")) ;; matlab-shell-run-region doesn't seem to
 			   ;; make *matlab* buffer contents easily
 			   ;; available, so :results output currently