Rüdiger Sonderfeld <ruediger@c-plusplus.de> writes:

> Looks good.  But I don't think `turn-on-flyspell-prog' is needed 
> because  `flyspell-prog-mode' already turns the mode on 
> unconditionally.  (Although  maybe the latter should be 
> reconsidered.) 

You are right. The following works well.