(calc-date-notation): Check to see if the format is whitespace

instead of only the empty string.

lisp/ChangeLog

+2009-11-02  Jay Belanger  <jay.p.belanger@gmail.com>
+
+	* calc/calc-forms.el (calc-date-notation): Allow a "blank string"
+	to be made up of whitespace.
+
 2009-11-02  Chong Yidong  <cyd@stupidchicken.com>
 
 	* minibuffer.el (read-file-name): Don't use file dialogs for

lisp/calc/calc-forms.el

@@ -81,7 +81,7 @@
 (defun calc-date-notation (fmt arg)
   (interactive "sDate format (e.g., M/D/YY h:mm:ss): \nP")
   (calc-wrapper
-   (if (equal fmt "")
+   (if (string-match-p "\\`\\s-*\\'" fmt)
        (setq fmt "1"))
    (if (string-match "\\` *[0-9] *\\'" fmt)
        (setq fmt (nth (string-to-number fmt) calc-standard-date-formats)))