Ch6 HW1

Definition: A predicate is a function that takes in an argument that can be anything, and returns a boolean.

1. Write find-all, which return a list of all items in the sequence that match the given item, possibly with an unusual :test. Also :test-not t should give the opposite results (include items that would be excluded, and vice versa).

    (defun find-all (item sequence 
                     &key (test #'eql) test-not)
            ...)
   

2. Write a function to break a list into two lists, the first where the predicate is satisfied, the second where it is not satisfied.

    (defun partition-if (pred list)
        ;; define satisfies-list and not-satisfies-list
        ;; ...
       (values satisfies-list not-satisfies-list))
   

TO BE CONTINUED