blob: 8a53853e3ab2347847ec907a83e37465daebf2a6 (
plain) (
blame)
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
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
|
package main
import "fmt"
type T func(t T) T
// LOGIC
var (
_true T = func(x T) T { return func(y T) T { return x } }
_false T = func(x T) T { return func(y T) T { return y } }
_not T = func(b T) T { return b(_false)(_true) }
_and T = func(b1 T) T { return func(b2 T) T { return b1(b2)(_false) } }
_or T = func(b1 T) T { return func(b2 T) T { return b1(_true)(b2) } }
)
// CHURCH NUMERALS
var (
_zero T = func(f T) T { return func(x T) T { return x } }
_succ T = func(n T) T {
return func(f T) T {
return func(x T) T {
return f(n(f)(x))
}
}
}
_pred T = func(n T) T {
return func(f T) T {
return func(x T) T {
return n(func(g T) T { return func(h T) T { return h(g(f)) } })(func(u T) T { return x })(func(a T) T { return a })
}
}
}
_one T = _succ(_zero)
)
// HELPERS - not pure lambda calculus
func readBool(b T) bool {
var res bool
var closureTrue T = func(t T) T {
res = true
return t
}
var closureFalse T = func(t T) T {
res = false
return t
}
b(closureTrue)(closureFalse)(func(t T) T { return t })
return res
}
func readChurch(n T) int {
res := 0
var closurePlusOne T = func(t T) T {
res++
return t
}
n(closurePlusOne)(func(t T) T { return t })
return res
}
func main() {
fmt.Println("LOGIC")
fmt.Println("-------------")
fmt.Println("TRUE/FALSE")
fmt.Println(readBool(_true))
fmt.Println(readBool(_false))
fmt.Println("NOT")
fmt.Println(readBool(_not(_true)))
fmt.Println(readBool(_not(_false)))
fmt.Println("AND")
fmt.Println(readBool(_and(_true)(_true)))
fmt.Println(readBool(_and(_true)(_false)))
fmt.Println(readBool(_and(_false)(_true)))
fmt.Println(readBool(_and(_false)(_false)))
fmt.Println("OR")
fmt.Println(readBool(_or(_true)(_true)))
fmt.Println(readBool(_or(_true)(_false)))
fmt.Println(readBool(_or(_false)(_true)))
fmt.Println(readBool(_or(_false)(_false)))
fmt.Println("\nCHURCH NUMERALS")
fmt.Println("-------------")
fmt.Println("ZERO/SUCC")
fmt.Println(readChurch(_zero))
fmt.Println(readChurch(_one))
fmt.Println(readChurch(_succ(_one)))
fmt.Println(readChurch(_succ(_succ(_one))))
fmt.Println("PRED")
fmt.Println(readChurch(_pred(_one)))
fmt.Println(readChurch(_pred(_succ(_one))))
fmt.Println(readChurch(_pred(_succ(_succ(_one)))))
}
|
