בְּרֵאשִׁ֖ית

.gitignore

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+*.fasl
+*.dx32fsl
+*.dx64fsl
+*.lx32fsl
+*.lx64fsl
+*.x86f
+*~
+.#*

README.org

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+* =cl-oju=
+
+A few Clojure idioms I missed from Common Lisp.
+
+Probably there are better libraries than this you should use.
+

cl-oju.asd

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+(defsystem "cl-oju"
+ :version "0.0.1"
+ :author "John Jacobsen"
+ :license "TBD"
+ :depends-on ("trivialtests")
+ :components ((:module "src"
+ :components
+ ((:file "main"))))
+ :description "Some Clojure-ish thingies")

src/main.lisp

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+(defpackage cl-oju
+ (:use :cl :trivialtests)
+ (:export :slurp
+ :spit
+ :take
+ :drop
+ :frequencies
+ :interpose
+ :partition-all
+ :rand-nth
+ :rand-int
+ :range
+ :repeatedly))
+(in-package :cl-oju)
+
+(defun slurp (infile)
+ (with-open-file (instream infile :direction :input :if-does-not-exist nil)
+ (when instream
+ (let ((string (make-string (file-length instream))))
+ (read-sequence string instream)
+ string))))
+
+(defun spit (name s)
+ (with-open-file (stream name
+ :direction :output
+ :if-exists :supersede)
+ (write-string s stream)))
+
+(defun range (n)
+ (loop for x upto (1- n) collect x))
+
+(defun take (n l)
+ (loop for x in l repeat n collect x))
+
+(defun drop (n l)
+ (nthcdr n l))
+
+(dotests
+ (test= (drop 3 (range 10))
+ '(3 4 5 6 7 8 9)))
+
+(defun rand-nth (l)
+ (nth (random (length l)) l))
+
+(defun interpose (sep coll)
+ (cdr (loop for x in coll append (list sep x))))
+
+(dotests
+ (test= (interpose :sep nil) nil)
+ (test= (interpose :sep '(1)) '(1))
+ (test= (interpose :sep '(1 2 3)) '(1 :SEP 2 :SEP 3)))
+
+(defun partition-all (cell-size step-size lst)
+ (loop for cell on lst
+ by #'(lambda (lst1) (nthcdr step-size lst1))
+ collecting (take cell-size cell)))
+
+(dotests
+ (test= (partition-all 2 2 '(a b c d))
+ '((a b) (c d)))
+ (test= (partition-all 2 1 '(a b c d))
+ '((a b) (b c) (c d) (d))))
+
+;; Adapted from https://codereview.stackexchange.com/a/223128:
+(defun frequencies (lst)
+ (let ((m (make-hash-table :test #'equalp)))
+ (loop for e in lst
+ do (incf (gethash e m 0)))
+ (loop for k being the hash-key of m
+ using (hash-value v)
+ collect (list k v))))
+
+(defun rand-int (n) (random n))
+
+(defun repeatedly (n f)
+ (loop repeat n collect (funcall f)))