i mean that it would be fairly easy to change say Apache::Registry so that it can work in one of the two modes i.e. closure/non-closure way..
'cause it is a matter of different way of concatenation of strings, before compiling the script..
There is no way of avoiding the closure issue. By definition mod_perl handlers are subroutines - you can't get around it - so there is no way to avoid closures if you're just wrapping existing code.