Perl: File::Path::mkpath results in error: "No such file or directory"

I was running a Perl script that came with ACE to generate doxygen documentation. When trying to run it on Windows via Cygwin, I got the following mysterious error:

... : No such file or directory at line …

How 'closures' work in Javascript (and Perl)

When I was learning Perl, the concept of a "closure" was one of the more difficult for me. And the first time around, I didn't really get it. So, I put it aside for later and didn't really use them. It then promptly fell to the bottom of the pile and slipped through the cracks. I later started writing a lot of Javascript and re-encountered closures. This time, I was determined to understand what they are and how they work.