blob: 7cabfeaece2147e5b2f43f072880fccdd624d7a9 (
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
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
; LIB
(let! just (\[a]
["maybe" "just" a]))
(let! nothing (\[]
["maybe" "nothing"]))
(let! unsafe-at (\[n seq]
(match seq
[]
(fatal! "unsafe-at out of bounds")
otherwise
(match n
0
(head seq)
otherwise
(unsafe-at (- n 1) (tail seq))))))
(let! unpack-just (unsafe-at 2))
(let! kind (unsafe-at 1))
(let! map (\[f m]
(match (kind m)
"just" (just (f (unpack-just m)))
"nothing" (nothing))))
(let! and-then (\[f m]
(match (kind m)
"just" (f (unpack-just m))
"nothing" (nothing))))
; TESTING
;; (let! print-line! (\[s]
;; (print! (concat s "\n"))))
;; (let! a (just 10))
;; (let! b (nothing))
;; (map (+ 5) a)
;; (map (+ 5) b)
;; (and-then (\[n] (just (+ n 5))) a)
;; (and-then (\[n] (just (+ n 5))) b)
;; (let! m (just 10))
;; (match m
;; (just _)
;; (print-line! (fmt "found just {0}!" [(unpack-just m)]))
;; (nothing)
;; (print-line! "found nothing!"))
(let! exports [
just
nothing
unpack-just
kind
map
and-then
])
|
