This is true. I tried to do something with Piston, but I couldn't figure out what the type of anything should be, because I could inspect functions to see what

This is true. I tried to do something with Piston, but I couldn't figure out what the type of anything should be, because I could inspect functions to see what their parameter and return types were. I could follow examples, but they tended to use inline functions, which don't need to specify types. In Swift you can just Cmd+Click to do this (assuming SourceKit hasn't crashed) and it's very useful for that kind of exploration.