+(defun product-version-as-string (product)
+ "Return version number of product as a string.
+PRODUCT is a product structure which returned by `product-define'.
+If optional argument UPDATE is non-nil, then regenerate
+`product-version-string' from `product-version'."
+ (setq product (product-find product))
+ (or (product-version-string product)
+ (and (product-version product)
+ (product-set-version-string product
+ (mapconcat (function int-to-string)
+ (product-version product)
+ ".")))))
+