Nothing! I mean I personally just use defstruct unless I want inheritance, but that's certainly not because CLOS lacks anything. I meant "you" as in the person

Nothing! I mean I personally just use defstruct unless I want inheritance, but that's certainly not because CLOS lacks anything. I meant "you" as in the person I responded to, who wants immutable data structures with tightly coupled functions. It's because CLOS is among the most object oriented systems I know of that I used it as an example; there seem to be some basically orthogonal traits which nonetheless wind up highly correlated, and CLOS is the purest OO you can get this side of Smalltalk while looking different from what you see in Java or whatever.