Most ACL2 primitives are documented. Here is the definition of
again, with the documented topics highlighted. All of the links
below lead into the ACL2 reference manual. So follow these links if you
wish, but use your Back Button to return here!
(defun app (x y) (cond ((endp x) y) (t (cons (car x) (app (cdr x) y)))))
By following the link on endp we see that it is a Common Lisp
function and is defined to be the same as atom , which recognizes
endp has a guard. Since we are ignorning guards for
now, we'll ignore the guard issue on
So this definition reads ``to
x is an atom,
(cdr x) and
y and then cons
(car x) onto that.''