blob: 46b4dd5d99ccdd981e350d87bfa2bc2626f207d7 (
about) (
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
37
38
39
|
(functor ((algebraic-structs foldable make) (F (foldl foldr)))
(foldl foldr length find any every ->list)
(import (except scheme length) F
(only (chicken base) add1 call/cc))
(define (length xs)
(foldl (lambda (acc _) (add1 acc))
0
xs))
(define (find p? xs)
(call/cc
(lambda (k)
(foldl (lambda (acc e)
(if (p? e)
(k e)
acc))
#f
xs))))
(define (any pred xs)
(call/cc
(lambda (return)
(foldl (lambda (acc e)
(cond ((pred e) => return)
(else acc)))
#f
xs))))
(define (every pred xs)
(call/cc
(lambda (return)
(foldl (lambda (acc e)
(or (pred e) (return #f)))
#t
xs))))
(define (->list xs)
(foldr cons '() xs)))
|
