Wonderful
Wonderful to have this on iOS. It's a real Common Lisp implementation and it's really usable on mobile. If you already know what Common Lisp is, you'll know whether or not you want that; if you don't, you may well discover that you've been wanting it all along! My only slight criticism might be that the app's user interface is a bit idiosyncratic & doesn't have much documentation: I suspect there may be easier ways of doing things I'm doing in not-quite-easy ways (or even things I haven't thought of doing). Someone who was totally new to Lisp might find the very first steps more puzzling than they need to be, just because of trying to find their way round the UI. But that's a relatively minor point—basically it's almost too good to be true. Congratulations to the developer.