Add partion-by and take-while

README.md

@@ -33,6 +33,7 @@ Supported operators:
  neg?
  partial
  partition-all
+ partition-by
  partition-n (called "partition" in Clojure)
  pos?
  rand-int
@@ -43,6 +44,7 @@ Supported operators:
  sort-by
  spit
  take
+ take-while
 
 # Usage
 

src/main.lisp

@@ -126,3 +126,22 @@
 ;; You should just use `remove-if-not`!
 (defun filter (f l)
  (remove-if-not f l))
+
+(defun take-while (f l)
+ (loop for x in l
+ with ret
+ do (progn
+ (when (not (funcall f x))
+ (return (nreverse ret)))
+ (setq ret (cons x ret)))
+ finally (return l)))
+
+(defun partition-by (f l)
+ (when l
+ (let* ((fst (first l))
+ (fv (funcall f fst))
+ (run (cons fst
+ (take-while (lambda (x)
+ (equal fv (funcall f x)))
+ (rest l)))))
+ (cons run (partition-by f (nthcdr (length run) l))))))

src/package.lisp

@@ -12,6 +12,7 @@
  :neg?
  :partial
  :partition-all
+ :partition-by
  :partition-n
  :pos?
  :rand-int
@@ -21,4 +22,5 @@
  :sort-by
  :slurp
  :spit
- :take))
+ :take
+ :take-while))

test/main.lisp

@@ -90,3 +90,25 @@
  (cl-oju:filter (constantly t)
  (cl-oju:range 10))))
  (is (equal '(1 3 5) (cl-oju:filter #'oddp (cl-oju:range 6)))))
+
+(test take-while
+ (is (null (cl-oju:take-while #'evenp ())))
+ (is (equal '(0)
+ (cl-oju:take-while #'evenp (cl-oju:range 3))))
+ (let ((f (lambda (x) (< x 3))))
+ (is (equal '(0 1 2)
+ (cl-oju:take-while f (cl-oju:range 100))))))
+
+(test partition-by
+ (is (null (cl-oju:partition-by #'evenp ())))
+ (is (equal '((0) (1) (2))
+ (cl-oju:partition-by #'evenp
+ (cl-oju:range 3))))
+ (is (equal '((0) (1) (2))
+ (cl-oju:partition-by #'oddp
+ (cl-oju:range 3))))
+ (is (equal '((a a a) (b) (c c c) (b) (a a a))
+ (cl-oju:partition-by
+ (lambda (x) (eq 'b x))
+ '(a a a b c c c b a a a)))))
+