Actually I had simpler reasons for avoiding that.

The first is that I didn't want to depend on experimental 5.6 features without good reason.

The second, and more important, is that I tried to figure out what it would look like to declare and initialize a list of things that included arrays and hashes. It did not look pretty.

Anyways I think that the API that I came up with is both simple to explain and pretty flexible. Plus it works on 5.005. :-)