I only mention X12 to say that I know EDI. It's what I do at my job, all day, every day.
You have no trading partner? Okay, but somebody you know does! Nobody messes around with EDIFACT unless they have to. So, you aren't writing a translator, just trying to understand the structure, and maybe learn some new perl skills along with it. I understand that. For my own work, I have not explored any of the EDI perl modules. We use a translator. I do have half a dozen awk scripts I use to make quick reports from EDI and application data files.