blob: fdfdbcf4e9007588d76edff051cf10c06d46f923 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
(defpackage #:lt-examples
(:use #:cl #:lambda-tools))
(enable-partial-eval-reader-macro)
;; http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers
(defun luhn (n)
(>> n #'reverse
#$(map 'list #'digit-char-p $char)
#$(mapcar #'*
(loop :for i :upto (length $digits) :collect (1+ (mod i 2)))
$digits)
#$(mapcar #$$(if (> $$x 9) (- $$x 9) $$x) $digits) ;; <-- nested partial eval
#$(zerop (mod (apply #'+ $digits) 10))))
(enable-lazy-eval-reader-macros)
(defun lazy-eg1 ()
(let* ((four #~(print (+ 2 2)))
(sum #~(+ (print 1) (print 2) (print 3) #!four)))
(list #!sum #!sum)))
;; prints
;; 1
;; 2
;; 3
;; 4
;; returns
;; (10 10)
|
