destroy

1 class C
2 {
3     struct Agg
4     {
5         static int dtorCount;
6 
7         int x = 10;
8         ~this() { dtorCount++; }
9     }
10 
11     static int dtorCount;
12 
13     string s = "S";
14     Agg a;
15     ~this() { dtorCount++; }
16 }
17 
18 C c = new C();
19 assert(c.dtorCount == 0);   // destructor not yet called
20 assert(c.s == "S");         // initial state `c.s` is `"S"`
21 assert(c.a.dtorCount == 0); // destructor not yet called
22 assert(c.a.x == 10);        // initial state `c.a.x` is `10`
23 c.s = "T";
24 c.a.x = 30;
25 assert(c.s == "T");         // `c.s` is `"T"`
26 destroy(c);
27 assert(c.dtorCount == 1);   // `c`'s destructor was called
28 assert(c.s == "S");         // `c.s` is back to its inital state, `"S"`
29 assert(c.a.dtorCount == 1); // `c.a`'s destructor was called
30 assert(c.a.x == 10);        // `c.a.x` is back to its inital state, `10`
31 
32 // check C++ classes work too!
33 extern (C++) class CPP
34 {
35     struct Agg
36     {
37         __gshared int dtorCount;
38 
39         int x = 10;
40         ~this() { dtorCount++; }
41     }
42 
43     __gshared int dtorCount;
44 
45     string s = "S";
46     Agg a;
47     ~this() { dtorCount++; }
48 }
49 
50 CPP cpp = new CPP();
51 assert(cpp.dtorCount == 0);   // destructor not yet called
52 assert(cpp.s == "S");         // initial state `cpp.s` is `"S"`
53 assert(cpp.a.dtorCount == 0); // destructor not yet called
54 assert(cpp.a.x == 10);        // initial state `cpp.a.x` is `10`
55 cpp.s = "T";
56 cpp.a.x = 30;
57 assert(cpp.s == "T");         // `cpp.s` is `"T"`
58 destroy!false(cpp);           // destroy without initialization
59 assert(cpp.dtorCount == 1);   // `cpp`'s destructor was called
60 assert(cpp.s == "T");         // `cpp.s` is not initialized
61 assert(cpp.a.dtorCount == 1); // `cpp.a`'s destructor was called
62 assert(cpp.a.x == 30);        // `cpp.a.x` is not initialized
63 destroy(cpp);
64 assert(cpp.dtorCount == 2);   // `cpp`'s destructor was called again
65 assert(cpp.s == "S");         // `cpp.s` is back to its inital state, `"S"`
66 assert(cpp.a.dtorCount == 2); // `cpp.a`'s destructor was called again
67 assert(cpp.a.x == 10);        // `cpp.a.x` is back to its inital state, `10`

int i;
assert(i == 0);           // `i`'s initial state is `0`
i = 1;
assert(i == 1);           // `i` changed to `1`
destroy!false(i);
assert(i == 1);           // `i` was not initialized
destroy(i);
assert(i == 0);           // `i` is back to its initial state `0`