I thought about using the mkdir() from perl, but my problem is that if a nested directory structure doesn't exist

i.e. /foo/bar/foobar/

then the code

mkdir("/foo/bar/foobar/");

is going to fail. Therefore I used a system call with the -p option so that any depth of directory will be created without failures.
As for the recursion bottoming out, just run the code. If it runs inifinitely then it doesn't bottom out. If it exits out, then it has a base case.

Thanks for the pointers.