stdlib.hl

(defun map (f lst) (if (= (length lst) 0) [] (++ [(f (head lst))] (map f (tail lst)))))

(defun filter (f lst) (if (= (length lst) 0) [] (if (f (head lst)) (++ [(head lst)] (filter f (tail lst))) (filter f (tail lst))))) 

(defun empty? (lst) (= (length lst) 0))

(defun foldr (f v lst) (if (empty? lst) 
                            v 
                            (f (head lst) (foldr f v (tail lst)))
                       ))

(defun reverse (lst) (if (empty? lst)
                         []
                         (++ (reverse (tail lst)) [(head lst)])))

(defun sum (lst) (if (empty? lst)
                     0
                     (+ (head lst) (sum (tail lst)))))

(defun member? (v lst) (if (empty? lst)
                           false
                           (if (= v (head lst))
                               true
                               (member? v (tail lst)))))

(defun common (lst1 lst2) (if (empty? lst1)
                             []
                             (if (member? (head lst1) lst2)
                                 (++ [(head lst1)] (common (tail lst1) lst2))
                                 (union (tail lst1) lst2))))

(defun unique (lst) (if (empty? lst)
                        []
                        (if (member? (head lst) (tail lst))
                            (unique (tail lst))
                            (++ [(head lst)] (unique (tail lst))))))

(defun curry (f arg) (lambda (arg2) (f arg arg2)))