ob-core: Small refactoring

* lisp/ob-core.el (org-babel-params-from-properties): Refactor code to
  avoid nesting `mapcar' calls.

lisp/ob-core.el

@@ -1409,33 +1409,31 @@ specified in the properties of the current outline entry."
   (save-match-data
     (list
      ;; DEPRECATED header arguments specified as separate property at
-     ;; point of definition
-     (let (val sym)
-       (org-babel-parse-multiple-vars
-	(delq nil
-	      (mapcar
-	       (lambda (header-arg)
-		 (and (setq val (org-entry-get (point) header-arg t))
-		      (cons (intern (concat ":" header-arg))
-			    (org-babel-read val))))
-	       (mapcar
-		#'symbol-name
-		(mapcar
-		 #'car
-		 (org-babel-combine-header-arg-lists
-		  org-babel-common-header-args-w-values
-		  (progn
-		    (setq sym (intern (concat "org-babel-header-args:" lang)))
-		    (and (boundp sym) (eval sym))))))))))
+     ;; point of definition.
+     (org-babel-parse-multiple-vars
+      (delq nil
+	    (mapcar
+	     (lambda (header)
+	       (let* ((arg (symbol-name (car header)))
+		      (val (org-entry-get (point) arg t)))
+		 (and val
+		      (cons (intern (concat ":" arg))
+			    (org-babel-read val)))))
+	     (org-babel-combine-header-arg-lists
+	      org-babel-common-header-args-w-values
+	      (let ((sym (intern (concat "org-babel-header-args:" lang))))
+		(and (boundp sym) (symbol-value sym)))))))
      ;; header arguments specified with the header-args property at
-     ;; point of call
+     ;; point of call.
      (org-babel-parse-header-arguments
       (org-entry-get org-babel-current-src-block-location
-		     "header-args" 'inherit))
-     (when lang ;; language-specific header arguments at point of call
-	 (org-babel-parse-header-arguments
-	  (org-entry-get org-babel-current-src-block-location
-			 (concat "header-args:" lang) 'inherit))))))
+		     "header-args"
+		     'inherit))
+     (and lang	 ; language-specific header arguments at point of call
+	  (org-babel-parse-header-arguments
+	   (org-entry-get org-babel-current-src-block-location
+			  (concat "header-args:" lang)
+			  'inherit))))))
 
 (defvar org-src-preserve-indentation) ;; declare defcustom from org-src
 (defun org-babel-parse-src-block-match ()