demos/objects/objects-wiki.c

   1 #include "cll1.h"
   2
   3 /* This is C<<1 rewrite of object polymorphism from
   4    http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming */
   5
   6 def_type(Animal);
   7
   8 def_mem(Actions)
   9 {
  10  void method(init) (Animal self, str name);
  11  str method(talk) (Animal self);
  12 };
  13
  14 def_obj(Animal)
  15 {
  16  interface(Actions);
  17  char *name;
  18 };
  19
  20 Animal construct(Animal) (Animal self, str name)
  21 {
  22  self->name = name;
  23  return self;
  24 }
  25
  26 str cat_talk(Animal self)
  27 {
  28  return "Meow!";
  29 }
  30
  31 str dog_talk(Animal self)
  32 {
  33  return "Arf! Arf!";
  34 }
  35
  36 Actions cat_actions(void)
  37 {
  38  Actions this=get_mem(Actions);
  39  this->talk = cat_talk;
  40  return this;
  41 }
  42
  43 Actions dog_actions(void)
  44 {
  45  Actions this=get_mem(Actions);
  46  this->talk = dog_talk;
  47  return this;
  48 }
  49
  50 program
  51 {
  52  int i;
  53  Animal animal[3];
  54  Actions cat = cat_actions();
  55  Actions dog = dog_actions();
  56
  57  animal[0] = get_obj(Animal, cat, "Missy");
  58  animal[1] = get_obj(Animal, cat, "Mr. Bojangles");
  59  animal[2] = get_obj(Animal, dog, "Lassie");
  60
  61  for_range(i, 0, 2)
  62  {
  63   printf("%s: %s\n", animal[i]->name, _(talk, animal[i]));
  64  }
  65 }