UserRPL HP 50G

[Brad Barton]

After seeing what you're trying to accomplish, debug4x might be a bit of overkill. Try WinHP here http://sourceforge.net/projects/winhp/ . I use it for generating programs for my HP-48, and it's very convenient because typing long programs into the 48 is pretty tedious using the calculator's keyboard. It could be exactly what you're looking for.

I'm not entirely sure that it will work with the HP-50, but it will produce files for the 49, so I don't see why it wouldn't work. It's not as deep as debug4x, but it doesn't need to be.