blob: f25ceb5e23d508c04dd78a109ea0859f496bb13c [file] [log] [blame]
(defun mapcar (fun list)
"Maps over the cars of `list` by running `fun` on each one.
List must be a cons-list, other sequences are not supported."
(if list
(cons (funcall fun (car list))
(mapcar fun (cdr list)))
nil))
(defun remove-if (predicate list)
"Returns a copy of `list` with elements satisfying `predicate`
removed."
(if (not list)
nil
(if (funcall predicate (car list))
(remove-if predicate (cdr list))
(cons (car list)
(remove-if predicate (cdr list))))))
(defun remove-if-not (predicate list)
"Returns a copy of `list` with elements not satisfying `predicate`
removed."
(remove-if (lambda (val)
(not (funcall predicate val)))
list))
(defun reduce (fun list (initial-value nil))
"Combines elements of `list` into one element using `fun`. `fun` must
accept two arguments and return the result of combining those
arguments. The first argument will be the result so far and the second
will be the n-th item of the list. For the first item of the list, the
result so far will be `initial-value`, or `nil` by default."
(if (nilp list)
initial-value
(reduce fun (cdr list)
(funcall fun initial-value
(car list)))))