Keep calm and read the Common Lisp specification (http://clhs.lisp.se/Body/f_firstc.htm http://clhs.lisp.se/Body/f_firstc.htm) There are first, etc... accessor

Keep calm and read the Common Lisp specification (http://clhs.lisp.se/Body/f_firstc.htm http://clhs.lisp.se/Body/f_firstc.htm) There are first, etc... accessors (other Lisps might define them too, it is so easy to implement). People are encouraged to use them, especially for lists, and are even encouraged to not use them but prefer objects with named slots. The general advice is to reserve C..R functions for trees, but this is actually rarely needed, especially when using pattern matching.