Good call with the casting issue. I'd been seeing that that wasn't working correctly but I just now figured it out.

Gisp lacked the ability to have function arguments actually be functions themselves. Gsp gets around this by casting __all__ (a lazy move, I know) functions to interface{} then to func([arg core.Any]+) core.Any.

I do stop this behavior for a certain whitelist - I need to add int/float64/bool/string to that list I think.

This was definitely just a first step. I think getting the Prelude to work is by far the coolest part. It did actually take a lot of trial and error hacking gisp -> gsp to get it working.

After this I will probably look into self-hosting documentation and maybe a cookbook.