Just made a quick test on my pet project using :clamp (not clamp experimental) and since most CL is exported, it's pretty compatible and works without much effort. So far so good. I'm gonna test the experimental part this week end.
I did find a better way to export everything. By using defpackage-plus, you can define a package definition clause that imports and exports every symbol that doesn't have a naming conflict with the current package. Exporting all of the symbols in :cl becomes just using this clause on :cl.
That's only ssyntax. a.b is rewritten as (get a b) where get is a generic function. You may be able to use set-funcallable-instance-function to get something closer to what arc supplies. Also there are a lot of edge cases with the ssyntax since you have to be within a w/ssyntax block. There is one included in def, so you can use ssyntax in function definitions, but you can't use it at the toplevel.
I wouldn't spend too much time on it. malisper truly has the right idiomatic approach with packages. I was mostly just flailing around with the little bit of Common Lisp I understand.
