JSONParser.save

1 auto json = JSONParser(q{
2     [
3         {
4             "name": "A",
5             "ability": "doFoo",
6             "health": 30
7         },
8         {
9             "name": "B",
10             "ability": "doBar",
11             "health": null
12         },
13         {
14             "name": "C",
15             "inherits": ["A", "B"],
16             "ability": "doTest"
17         }
18     ]
19 });
20 
21 static class EntityMeta {
22     string name;
23     string[] inherits;
24 }
25 
26 static class Entity : EntityMeta {
27     string ability;
28     int health = 100;
29 }
30 
31 JSONParser[string] states;
32 Entity[string] entities;
33 foreach (index; json.getArray) {
34 
35     // Get the metadata and save the state
36     auto state = json.save;
37     auto meta = json.getStruct!EntityMeta;  // Efficient and quick way to fetch the two attributes
38     states[meta.name] = state.save;
39 
40     // Create the object
41     auto entity = new Entity();
42 
43     // Inherit properties
44     foreach (parent; meta.inherits) {
45 
46         // Get the parent
47         auto parentState = states[parent].save;
48 
49         // Inherit its values
50         parentState.updateStruct(entity);
51 
52     }
53 
54     // Now, add local data
55     state.updateStruct(entity);
56 
57     entities[entity.name] = entity;
58 
59 }
60 
61 const a = entities["A"];
62 assert(a.name == "A");
63 assert(a.ability == "doFoo");
64 assert(a.health == 30);
65 
66 const b = entities["B"];
67 assert(b.name == "B");
68 assert(b.ability == "doBar");
69 assert(b.health == 100);
70 
71 const c = entities["C"];
72 assert(c.name == "C");
73 assert(c.ability == "doTest");
74 assert(c.health == 30);  // A had explicitly stated health, B did not — inherited from A.
75                          // Otherwise impossible without saving states.
76