reflection/basics_json

• C

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  #include <basics_json.h>
  #include <stdio.h>
   
  typedef struct {
      float x, y;
  } Position;
   
  int main(int argc, char *argv[]) {
      ecs_world_t *ecs = ecs_init_w_args(argc, argv);
   
      // Register component as usual
      ECS_COMPONENT(ecs, Position);
   
      // Add reflection data to component
      ecs_struct(ecs, {
          .entity = ecs_id(Position), // Make sure to use existing id
          .members = {
              { .name = "x", .type = ecs_id(ecs_f32_t) }, // builtin float type
              { .name = "y", .type = ecs_id(ecs_f32_t) }
          }
      });
   
      // Create entity with Position as usual
      ecs_entity_t ent = ecs_entity(ecs, { .name = "ent" });
      ecs_set(ecs, ent, Position, {10, 20});
   
      // Convert position component to JSON
      const Position *ptr = ecs_get(ecs, ent, Position);
      char *str = ecs_ptr_to_json(ecs, ecs_id(Position), ptr);
      printf("Position = %s\n", str);
      ecs_os_free(str);
   
      // Convert entity & all its components to json
      str = ecs_entity_to_json(ecs, ent, NULL);
      printf("ent = %s\n", str);
      ecs_os_free(str);
   
      // {
      //     "path":"ent", 
      //     "ids":[["Position"]], 
      //     "values":[{
      //         "x":10, 
      //         "y":20
      //     }]
      // }
   
      ecs_fini(ecs);
  }

• C++

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  #include <basics_json.h>
  #include <iostream>
   
  struct Position {
      float x;
      float y;
  };
   
  int main(int, char *[]) {
      flecs::world ecs;
   
      // Register component with reflection data
      ecs.component<Position>()
          .member<float>("x")
          .member<float>("y");
   
      // Create entity with Position as usual
      flecs::entity e = ecs.entity("ent")
          .set<Position>({10, 20});
   
      // Convert position component to JSON string
      const Position& p = e.get<Position>();
      std::cout << ecs.to_json(&p) << "\n"; // {"x":10, "y":20}
   
      // Convert entity to JSON
      std::cout << e.to_json() << "\n";
   
      // {
      //     "path":"ent", 
      //     "ids":[["Position"]], 
      //     "values":[{
      //         "x":10, 
      //         "y":20
      //     }]
      // }
  }