lantern.util source code

1 module lantern.util;
2 
3 import core.time;
4 
5 import std.typecons;
6 
7 template MemberTypeOf(T)
8 {
9     alias MemberTypeOf(string name) = typeof(__traits(getMember, T.init, name));
10 }
11 
12 template FieldTypeOf(T)
13 {
14     alias FieldTypeOf(string name) = typeof({
15         auto value = __traits(getMember, T.init, name);
16         return value;
17     }());
18 }
19 
20 unittest
21 {
22     struct Test
23     {
24         int n;
25 
26         float test()
27         {
28             return 1.0f;
29         }
30     }
31 
32     alias MemberType = MemberTypeOf!Test;
33     alias FieldType = FieldTypeOf!Test;
34 
35     static assert(is(MemberType!"n" == int));
36     static assert(is(FieldType!"n" == int));
37 
38     alias F = float();
39     static assert(is(MemberType!"test" == F));
40     static assert(is(FieldType!"test" == float));
41 }
42 
43 Nullable!Duration toDuration()(Nullable!long d)
44 {
45     if (d.isNull)
46         return Nullable!Duration.init;
47 
48     return nullable(d.get().hnsecs);
49 }
50 
51 unittest
52 {
53     Nullable!long a;
54     Nullable!long b = 1.hnsecs.total!"hnsecs";
55     Nullable!long c = 10.seconds.total!"hnsecs";
56 
57     assert(a.toDuration().isNull);
58     assert(b.toDuration() == nullable(1.hnsecs));
59     assert(c.toDuration() == nullable(10.seconds));
60 }
61 
62 Nullable!Duration toDuration()(Nullable!real d)
63 {
64     if (d.isNull)
65         return Nullable!Duration.init;
66 
67     import std.math : round;
68 
69     return nullable((cast(long) round(d.get())).hnsecs);
70 }
71 
72 unittest
73 {
74     Nullable!real a;
75     Nullable!real b = 1.hnsecs.total!"hnsecs";
76     Nullable!real c = 10.seconds.total!"hnsecs";
77 
78     assert(a.toDuration().isNull);
79     assert(b.toDuration() == nullable(1.hnsecs));
80     assert(c.toDuration() == nullable(10.seconds));
81 }