VariantPointerTo

1 import std.meta : AliasSeq;
2 
3 alias Types = AliasSeq!(byte, short, int, long,
4                         ubyte, ushort, uint, ulong,
5                         float, double, real,
6                         char, wchar, dchar);
7 
8 alias V = VariantPointerTo!Types;
9 
10 V v;
11 assert(v.isNull);
12 v = null;
13 assert(v.isNull);
14 assert(!v);
15 
16 foreach (T; Types)
17 {
18     static assert(!__traits(compiles, { T[] a; v = &a; }));
19     static assert(!__traits(compiles, { v.peek!(T[]*); }));
20 
21     // assignment from stack pointer
22     T a = 73;
23     T a_ = 73;
24     v = &a;
25     assert(v == &a);
26     assert(v != &a_);
27     assert(v);
28     foreach (U; Types)
29     {
30         static if (is(T == U))
31         {
32             assert(v.peek!U);
33             assert(*(v.peek!U) == a);
34         }
35         else
36             assert(!v.peek!U);
37     }
38 
39     // assignment from heap pointer
40     T* b = new T;
41     T* b_ = new T;
42     *b = 73;
43     *b_ = 73;
44     v = b;
45     assert(v == b);
46     assert(v != b_);
47     assert(v);
48     foreach (U; Types)
49     {
50         static if (is(T == U))
51         {
52             assert(v.peek!U);
53             assert(*(v.peek!U) == *b);
54         }
55         else
56             assert(!v.peek!U);
57     }
58 
59 }